Citation
The effect of DAF on speech production of post-lingual cochlear implant users

Material Information

Title:
The effect of DAF on speech production of post-lingual cochlear implant users
Creator:
Grey, Polly Shipp, 1941-
Publication Date:
Language:
English
Physical Description:
viii, 143 leaves : ill. ; 29 cm.

Subjects

Subjects / Keywords:
Auditory perception ( jstor )
Cochlear implants ( jstor )
Consonants ( jstor )
Deafness ( jstor )
Error rates ( jstor )
Hearing aids ( jstor )
Hearing loss ( jstor )
Speech production ( jstor )
Spoken communication ( jstor )
Vowels ( jstor )
Cochlear implants -- Evaluation ( lcsh )
Communication Processes and Disorders thesis Ph.D
Deaf -- Rehabilitation ( lcsh )
Dissertations, Academic -- Communication Processes and Disorders -- UF

Notes

Thesis:
Thesis (Ph.D.)--University of Florida, 1992
Bibliography:
Includes bibliographical references (leaves 134-142)
General Note:
Typescript.
General Note:
Vita.
Statement of Responsibility:
by Polly Shipp Grey.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
Copyright [name of dissertation author]. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Resource Identifier:
028084739 ( ALEPH )
26585628 ( OCLC )
AJG6141 ( NOTIS )

Downloads

This item has the following downloads:


Full Text











THE


EFFECT


OF DAF ON SPEECH PRODUCTION
COCHLEAR IMPLANT USERS


OF POST-LINGUAL


POLLY


SHIPP


GREY


A DISSERTATION PRESENTED '
THE UNIVERSITY OF FLORIDA


rO THE GRADUATE SCHOOL OF
SIN PARTIAL FULFILLMENT















DEDICATION


This dissertation


lovingly dedicated


Edward


Crawford


Shipp


Edward Rodgers Grey


Polly Moore


Shipp


Virginia


Farrell


Grey


(1911-1963)














ACKNOWLEDGEMENTS


I wish


express


deepest


appreciation


gratitude


to Dr.


Patricia


Kricos


her


outstanding


guidance,


steadfast


encouragement


during


graduate


studies


throughout


this


project.


am al


indebted


to Dr.


Alice


Dyson


her


many


contributions


completion


of this


project.


wish


thank


other


members


committee


who


have


given


so generously


their


time,


shared


their


knowledge,


graduate


and


have


studies


, Dr.


been


so supportive


Alice


. Holmes,


me during


. Kemker,


. Dr


. Otto


von


Mering


would


Gerhardt,


also


like


Michael


express


Crary,


and


thanks


Ernest


to Dr.


Walden


Kenneth


their


assistance

problems,


with

and c


calibration,


collection


resolving


of pilot


instrumentation


data.


am grateful


to Phonic


Ear


Corporation


and


Unitron


Industries


, Incorporated


loaning


me the


necessary


equipment


and


their


understanding


when


data


collection


took


longer


than


anticipated.


am especially


grateful


Robert


Mendoza


of Phonic


Ear


Corporation


and


John


Seamans


Unitron


Industries


Incorporated


.for


their


interest


r








would


like


express


gratitude


to Mrs.


Ruby


Moore,


& R Enterprises,


her


contribution


completion


Special


this

thanks


project


to Kit


typing

Evans


final


Brinsko


manuscript.

her


friendship


her


sense


of humor,


many


hours


contributed


helping


transcribe


data.


must


also


thank


some


others


whose


friendship


been


so steadfast,


Ann


Pierson,


Darlene


Hooker,


Lori


Gonzalez,


Jamie


Barron


Schwartz.


want


support, esp

Finally


thank


ecially


give


family


Watkins


love


their


Adams

and


encouragement


Saunders,


thanks


husband,


Barry


who


fills


life


with


so much


happiness.



















TABLE OF CONTENTS


ACKNOWLEDGEMENTS..................................


ABSTRACT..........................................


CHAPTERS


Vii


INTRODUCTION..........................


REVIEW OF THE LITERATURE................


Hearing. ....... ........................
Normal Speech Production and
Perception.........................


Vowels. . ..
Consonants.......................
Effect of Hearing Loss on Speech
Production and Perception...
Cochlear Implants...............
Differences in Cochlear Implants.
Delayed Auditory Feedback........
Summary..........................


000....

.......

t......
.0..000.

.......
.......
* 555
* *C

* CSCCC
* C S *


METHODOLOGY.................. ...........


Subjects..............
Test Procedures.......
Equipment.............
Conditions...........
Methods and Materials.
Analysis of Data......


"...............I.

.0".0....00...0....


"... ..... .. ... ..
....'..........Q..
* S tC* *SC ***
* C S Ct *SCC S*
* C C S SS CC ** S C S
* .S SC CS SC C* SS SC CS
* S SC CC C S *t S*SC
S S S SCSCSS C C S Ct C


DAF Effect on Reading and Counting
Duration...........................
DAF Effect on Number of Consonant
and Vowel Errors.................
Performance with Cochlear Implant


Pace


RESULTS.









DISCUSSION..... ............. ........


Reading a
Consonant
Vowel Err
Cochlear
Types of
Summary..
Conclusio:


nd Coun
Errors
ors....
Implant
Speech
....t...


ris..


ting


Vers
Error


Duration...

us..... Hearing
us Hearing


s.


* *..


* 10**

* 4S1e


* ..


Aid



* e


*400
* 0*-


APPENDIX


TOTAL
DURING


NUMBER OF
READING.


CONSONANT
".'.......


ERRORS


APPENDIX


TOTAL NUMBER
READING.....


OF VOWEL
"........


ERRORS


DURING


APPENDIX


TOTAL
DURING


NUMBER OF
COUNTING


CONSONANT
........0..


ERRORS


APPENDIX


TOTAL NUMBER
COUNTING.....


OF VOWEL
........


ERRORS
.* .. ...


DURING
t.......


APPENDIX


APPENDIX


DURATION,
READING..


DURATION,
COUNTING.


IN SECONDS,
". .... ......


IN SECONDS


DURING


DURING


)0****e* ..t.... 0*t****S


BIOGRAPHICAL


SKETCH ............ .. ..........


REFERENCES (1~1)(1~(1111(1111()))rll((~))((l








Abstract


the


Dissertation


University


Requirements


of Florida


the


Presented


Partial


Degree


Doctor


re Graduate
Fulfillment


School


of Philosophy


THE


EFFECT


OF DAF


ON SPEECH


COCHLEAR


Polly


PRODUCTION


IMPLANT


Shipp


OF POST-LINGUAL


USERS


Grey


May


1992


Chairman:


Co-Chairman:


Major


Patricia


Alice


Department


. Kricos


. Dy


Ph.D.


son,


Communication


Processes


Disorders


The


purpose


of this


study


was


to investigate


effect


of delayed


auditory


feedback


(DAF)


on the


speech


production


of adult


post-lingually


deafened


cochlear


implant


users.


Delayed


auditory


eedba


ck effects


on the


speech


production


of normal-hearing


individuals


are


well


documented


and


have


also


been


reported


in a group


of hearing


-impaired


children


using


hearing


aids.


The


eight


subjects


five


women


and


three


men,


ranged


aged


from


to 61


years.


wore


Cochlear


Corporation


Nucleus


22-Channel


cochlear


implant


had


completed


the


recommended


post


-implant


aural


rehabilitation


protocol.


The


subjects


were


tested


under


simultaneous


auditory


feedback


(SAF)


and


delayed


auditory


feedback


(DAF)


three


conditions


cochlear


implant,


hearing


aid,


no amplification


In each


condition


they


read


a passage








Alphabet and


were


analyzed


for total


number of


consonant and


vowel


errors using the


Program to


Examine


Phonetic and


Phonologic Evaluation Records


(PEPPER).


Differences between


the SAF


and DAF


conditions


the duration


of reading


and of


counting were also measured


in seconds.


The data


were subjected


to a


Friedman Two-Way


Analysis


of Variance


(ANOVA).


There were no statistically


significant differences

task or condition, sugg


performance


regardless of


testing the absence of


a DAF


effect.


However,


an apparent


effect was detected during


transcription of


recorded data.


This was


investigated


further


calculating


effect size values between SAF/DAF


and


the different experimental


tasks.


Large effect size


values under DAF were obtained


for:


reading duration


with


the cochlear


implant


(0.96)


the hearing


aid


(0.99)


counting vowel


errors


(1.02)


with


the cochlear


implant.


These


large effect


sizes


indicated


that


subjects


took longer to


read


the passage when wearing


either device


and more

cochlear


vowel cc

implant.


huntingg


errors were made


Effect size


when wearing the


value comparisons between


two devices


indicated a


large DAF


effect


size


(0.81)


vowel


reading


errors with


the cochlear


implant.


In summary


a possible DAF


effect


was evident


in some conditions but was


not supported by statistical


testing.














CHAPTER


INTRODUCTION


The


the


most


United


prevalent


States


chronic

hearing


disability

impairment


in the

(Punch,


population

1983).


is estimated


that


million


Americans


have


some


degree


hearing


loss


approximately


these


people


are


profoundly


hearing


impaired,


i.e.


, deaf


(National


Center


Health


Statistics,


1982)


In this


group


of profoundly


hearing-impaired


people


are


some


who


no longer


receive,


have


never


received,


benefit


from


conventional


amplifica-


tion.


The


reasons


this


vary


but


include


increases


symptoms


tinnitus


or vertigo


an intolerance


vibrotactile


sensations


that


can


accompany


the


use


powerful


amplification


(Eisenberg


, Berliner,


House,


Edgerton,


1983)


as well


as the


risk


of causing


additional


damage


to the


ear


(Humes


Bess,


1981) .


Lastly,


there


some


cases


profound


hearing


loss


inability


overcome


the


hearing


loss


via


amplification.


The


critical


influence


of hearing


, and


effects


varying


degrees


hearing


well


loss,


established


acquis


(Calvert


ition


of speech


Silverman,


and


1983;


language


Gold,


1980;










production


of the


post-lingually


hearing


impaired,


individuals


who


developed


hearing


loss


after


acquiring


speech


and


language,


been


described


as to "generally


consisting]

Smith, 1989).


patterns


adult,


of anecdotal

However, a


in a normal-hearing


Zimmerman


reports"


comparison


and


Rettaliata


(Seyfried,

n study of


a post-lingually


(1981),


Hutchinson,


! articulatory


deafened


suggested


importance

maintaining


of auditory

"speech co


information


ordinative


in monitoring


structures


Boothroyd


(1988)


cited


the


significant


role


hearing


as a


feedback


system


conservation


post-lingually


some


hearing


hearing-impaired


and


restoration


impaired.

individuals


was


of speech


stated


no longer


in the


earlier,


receive,


or have


never


received,


benefit


from


conventional


amplification.


These

which


people no

Boothroyd


longer

was re


have


ferring.


access


The


the


cochle


feedback

ar implan


system t

t offers


an alternative


to conventional


amplification.


In 1957


Djourno


Eyries


reported


their


findings


following


stimulation


the


acoustic


nerve


the


direct


application


an electrode


Simmons,


1966) .


Their


patient,


a 50-year-old


deaf


man,


described


sound


sensations


experienced


as sounding


like


"crickets"


or a


"roulette


wheel


In addition


he reported


an awareness


of background


.e.,










techniques


and


design


of stimulating


devices,


resulted


interest


others


medical


community


By


1969


William


. House


and


Jack


Urban,


an electrical


engineer


, had


developed

(House, 1


the


976) .


first


cochlear


Cochlear


implant


implants


are


the United


surgically


States


implanted


devices


that


allow


profoundly


hearing


impaired


experience

electrode


sound.

(channel)


The f

but,


first

with


implants

better


used


single


technology


continuing


research


, some


of today


s devices


make


use


multiple


electrodes


(multichannel)


All


the


implants


enable


user


to experience


sound


sensation


stimulating


auditory


nerve.


Today


there


are


more


than


3000


people


who


have


rece


ived


either


a single


or multichannel


cochlear


implant


(Goldstein


Friedelwald,


1988).


In general,


cochlear


can


implant


be attributed


to the


be said


variable.


that


differences


effectiveness


Some


among


variability

people


receiving


an implant,


.e.


, differences


in audiological,


medical,


psychological,


social,


and


communication


histories,


as well


as the


type


of device


implanted.


Performance


with


an implant


can


range


from


the


individual


who


can


only


distinguish


traffic


between


versus


environmental


a doorbell


sounds


a person


(for


who


example,


able


car

engage










regardless of type of


device,


is an


improvement


speechreading ability


(Lansing,


1988).


The speech


perception


of cochlear


implant recipients


who use single or multichannel


devices has


been well


documented


(Bilger,


1983;


Eddington,


1988;


Eisenberg,


al.,


1983


Holmes,


Kemker,


& Merwin


, 1987).


There has been


less


research


on the speech


production of


these


patients.


The device does seem


evidenced by the


to offer


reported


benefit


improvement


this area as

loudness control


and vocal


quality


that has


been attributed


to the user's


ability to self-monitor his/her speech productions


(Chouard


et al.,

& Hough,


1983;

1981;


Eisenberg

Fourcin


et al.,

et al.,


1983;

1983) .


Engelmann,


Waterfall,


These studies,


while


commenting on the speech


their subjects,


were not


designed


to specifically


investigate speech production


Some post-lingual


and many prelingual hearing-impaired have


significant


problems


communicating due


their poor speech.


Cowie and


Douglas-Cowie


(1982)


reported


that


one of


their


subjects carried a


letter explaining to


people


that his


slurred speech was due


to his deafness and not


to his being


drunk.


To better address


issue of


speech


production of


cochlear


implant


users,


more


research


needed.


The


focus


of this


research


project


was


to examine


effect










to obtain


objective


evidence


their


use


their


"new"


auditory


information


to monitor


their


speech


production.


Delayed


auditory


feedback


(DAF)


refers


experimentally


induced


time


delay


a speaker


s hearing


his/her


spoken


(Yates,


voice.


utterances


1963).


Normally,


within


Under


individual


approximately


conditions,


hears


one


as an


his/her


millisecond


individual


speaks


into


a microphone,


device


to introduce


a delay


transmiss


of hi


her


speech.


The


effects


on the


speech


of normal-hearing


individuals


were


noted


over


years


(Black,


1951;


Fairbanks,


1954,


1955;


Fairbanks


Guttman,


1958


Lee,


1950).


Some


effects


included


omissions,


substitutions,


repetitions


of sounds


as well


as changes


vocal


intensity.


The


effects


of DAF


on the


speech


production


of hearing-impaired


children


using


conventional


amplification


were


studied


Maxon,


Brackett,


Riordan


and


Pfeffer


, (1987).


They


reported


that


their


subjects


experienced


some


same


DAF


effects


on speech


production


that


had


been


noted


normal-hearing


subjects,


including


increase


amount


time


needed


to read


passage


and


to recite


rote


numbers,


an increase


in vocal


intensity.


They


concluded


that


their


subj


ects


were


making


use


some


minimal


auditory


cues,


suggesting


some


degree


*










users.


A demonstrated


effect


would


seem


suggest


that


the


cochlear


implant


user


was


making


use


of auditory


cues,


as did


the


hearing-impaired


children


discussed


the


Maxon-


et al.


(1987)


study


Specifically,


a population


eight


post-lingually


deafened


cochlear


implant


subjects


, the


research


questions


to be formulated


were:


there


a difference


between


the


SAF


and


conditions


duration


of reading


and


counting


cochlear


implant


users?


there


a difference


between


SAF


and


conditions


the


total


number


of consonant


vowel


errors


made


cochlear


implant


users


during


reading


and


counting


tasks?


there


a difference


between


SAF


and


conditions


duration


of reading


and


counting


cochlear


implant


users


when


wearing


a hearing


aid


alone?


Is there


a difference


between


the


SAF


and


conditions


the


total


number


consonant


vowel


errors


cochlear


implant


users


when


wearing


a hearing


alone


and


performing


reading


and


counting


tasks?















REVIEW


CHAPTER
OF THE


LITERATURE


There


are


however,


many


one


different


which


forms


unique


of communication;


to humans


speech.


Speech


communication


can


be d


escr


ibed


using


feedback


model


which


there


is a sender


(the


speaker),


a message,


and


receiver


(the


listener)


The


feedback


a combination


auditory,


visual,


tactile,


kinesthetic


experiences.


When


there


the


a disruption


case


of profound


the


hearing


auditory


oss


feedback


, meaningful


portion,


speech


perception


is terminated


and


speech


production


may


affected


(Zimmermann


& Rettaliata,


1981


Cowie,


Dougl


as-


Cowie


Kerr,


1982


Plant,


1984)


In order


to re-establish


auditory


eedback


mechanism,


dev


ices


have


been


developed


which


directly


stimulate


auditory


nerve.


These


devi


ces


are


called


cochlear


linniants


The


additional


auditory


information


understand


provided


speech


implant


auditorily


enabl


(Berliner,


some


Tonokawa,


users


Dye,


House,


1989;


Holmes,


Kemker


Merwin,


1987


Tye-Murray


Tyler,


1989)


and


enhances


speechreading


ability


(Ballantyne,


1985)


In addition,


researchers


have


reported










1983;


Leder,


Spitzer,


Kirchner,


Flevaris-Phillips,


Milner,


Rilchardson,


1986).


The


purpose


this


study


examine


the


re-


established f

investigating


eedback


the


system


effects


cochlear


of delayed


implant


auditory


users


feedback


the


speech


production


of cochlear


implant


users


with


post-


lingual


deafness.


This


chapter


will


review


normal


hearing,


speech


production


perception,


the


effects


delayed


auditory


feedback


on normal-hearing


and


hearing-impaired


individuals


(using


conventional


amplification),


and


speech


perception


and


production


cochlear


implant


users.


Hearing


The


ear


has


been


described


as having


several


functions


enable


us to interpret


sounds.


The


outer


ear


offers


protection


and


gives


some


enhancement


the


sound


stimulus.


The


middle


ear


acts


as an impedance


matching


network


thereby


restoring


acoustical


energy


that


would


otherwise


lost


the


sound


passes


through


the


inner


ear


or cochlea.


The


cochlea


once


was


thought


as a


very


sensitive


microphone;


however,


now


understood


that


is a series


of filters


which


pass


signals


one


frequency


and


rejects


signals


other


frequencies.


This


filtering


ability


results










Normal


Speech


Production


PercePtion


Verbal


communication


is a complex


series


of acts


dependent


sounds


upon


which,


the


when


speaker


producing


heard


a string


listener,


can


contrasting


decoded


the


message


understood.


This


process


usually


takes


place


with


ease


due


person


s knowledge


language


tern


anatomy


physiology


the


speech


hearing


structures.


Because


these


unique


structures,


human


beings


have


capacity


to learn


to produce,


recognize,


many


different


sounds.


In the


English


language


there


are


about


forty


phonemes,


classes


of sounds


that


differentiate


one


sound


from


another


(Ling


Ling,


1978;


Mackay,


1987) .


Speech


sounds


are


divid


ed into


two


large


groups,


vowels


consonants


, depending


upon


how


they


are


produced


and


their


acousti


character


stics.


In addition


ability


to produce


and


understand


these


speech


sounds


normal-hearing


listener


able


differentiate


whether


speaker


is a male,


female,


or a


child.


This


ability


result


the


vocal


folds


vibrating


at different


frequencies


depending


on the


sex


age


the


speaker.


This


vocal


fold


vibration


referred


as the


fundamental


freauencv


(FO).


The


fundamental


frequency


adult


males


typically


occurs


between


and










Vowels


Vowel


production


results


from


a combination


of exhaled


air


passing


tongue,


and


through


out


vibrating


mouth.


vocal


Changes


folds,


the


over


degree


which


shape


the


and


is open,


position


position


tongue


lips,


influence


and


acoustical


properties


the


produced


sounds


yielding


a distinct


fourteen


sounds


which


comprise


English


vowels


(Dew


& Jensen,


1979) .


The


shape


position


tongue


exert


greatest


influence


in differentiating


the


different


vowels.


Vowel


perception


result


of changes


in the


resonating


patterns


cavities


of concentrated


vocal


tract


acoustical


creating


energy


which


different


occur


different


frequencies.


These


patterns


of concentrated


energy


are


called


formants


and


are


numbered


from


lowest


highest


frequency.


Although


the


vowel


will


sound


most


natural


first


three


formants


are


heard,


the


first


two


formants


which


are


critical


differentiating


one


vowel


from


another


(MacKay,


1987).


Each


vowel


has


own


characteristic


formant


pattern


and


each


individual


his/her


own


characteristic


size


and


shaped


vocal


tract


result


that


two


different


speakers


will


pronounce


the


same


vowel


somewhat


differently.


Despite


these


differences










1987).


In order


a person


to perceive


those


critical


first


two


formants


they


need


to be


able


hear


the


range


to 1000


the


first


formant


(Fl)


and


between


to 3330


the


second


formant


(Skinner,


1978).


Diohthonas


are


phonemes


made


two


vowel


sounds


occur


as phonemes


which


glide


from


one


vowel


position


another.


The


frequency


of a diphthong


determined


first


the


formant


second


values


formant


of each


values


vowel


being


being


added


added


together


together


giving


approximation


the


frequency


range


the


particular


diphthong


(Ling


& Ling,


1978).


Consonants


Consonants


are


the


second


large


class


sounds


and


are


produced


changing


the


airflow


out


the


mouth.


The


manner


in which


the


flow


interrupted


yields


three


distinct


types


consonants


plosives,


which


result


when


airflow


completely


blocked


such


sounds


fricatives,


resulting


from


the


airflow


being


restricted


the


sounds


/f,v,e


nasals,


where


the


air


flow


directed


through


the


nose


the


sounds


In addition


the


above


types,


another


distinctive


.~~~~~ U -A.--


/Prt, k/;


,sh/;


/mn,0/.


I


-r I I


II


1










this


feature


which


allows


distinction


between


voiced


plosive


voicel


ess


cognate


During


production


of /b/


vocal


fold


vibration


the


rele


ase


the


occur


at approximately


the


same


time


(within


to 40 msec.)


in contrast,


there


a time


between


vibration


vocal


folds


and


the


release


(greater


than


to 40 msec.)


making


"voicele


speech


sound


(Dew


& Jensen,


1977).


Lisker


and


Abramson


(1964)


coined


the


term


"voice


onset


time


(VOT)"


to describe


relative


timing


the


consonant


release


and


the


onset


voicing.


Voicing


perception


dependent


on low


frequency


information,


usually


the


range


of 80


to 350


adult


speakers


and


at higher


frequencies


children


(Stevens,


1983)


The


range


of hearing


necessary


consonant


perception


varies


with


different


manner


production


and


also


within


either v

plosives


a particular


class


oiced


of consonants.


or voiceless


are


relatively


Plosives


U/P,


frequency


t, k/)

sounds


can


The

having


the


majority


1500


The


their


greatest


concentrated


energy


energy


between


found


between


4000


and


5000


and


the


energy


concentration


varies


from


1000


to 4000


Hz depending


on the


frequency


/b/


/P/


/b/


/b p/


/a, t/


/ k/










range


the


pair


approximately


3500


8000


and


the


/J,3 /


pair


around


2500


to 4500


Another


acoustic


cue


to differentiating


fricative


sounds


intensity


and


duration.


The


are


less


intense


and


of shorter


duration


than


S, 3/


the


phonemes


(Skinner,


1978)


Nasal


sounds


are


produced


the


sound


being


emitted


from


the


nose


rather


than


mouth.


They


are


voiced


are


characterized


frequency


nasal


"murmur"


the


range


to 300


In addition


to plosives,


fricatives,


and


nasals


there


are


other


called


consonant


slides


,j/)


sounds


and


which


resemble


semivowels


(/r,


vowels


1/).


and


are


Glides


are


characterized


changing


formants


and


semivowels


formant


configuration


similar


to vowels


but


more


restricted


total


frequency


region


(Skinner,


1978).


Finally,


the


consonant


equivalent


to the


diphthong


the


affricate.


The


affricate


is a combination


of a voiced


plosive

voiceless


combined

plosive


with


combined


voiced

with


fricative


(/dg/)


voiceless


or the


fricative


(/tJ/).


Effect


of Hearing


Loss on Snsseh Produnt I nit anti Dorrnn* I an
-- -- --- --- app -. .~ a -- --- -p~**


/s, 2/


/vlflh, e/~/


/8,2,


Lass


an SnsEch


Prnrilt~ti ah


Da rr an+ ; nh


*










their


frequency


components.


Cochlear


or inner-ear


hearing


loss


compromises


listener


receiving


that

g a d


filtering

istorted


system

signal,


resulting


any


at all


Depending


on the


severity


hearing


loss


the


signal


may


not


be recognized


, or heard,


stener


SSince


subjects


this


this


discussion


stud

will


are


post


focus


-lingually


research


deafened

reported


adults,

on their


speech


production


perception.


Speech


production


perception


studies


prelingual


well


Hudgins


population


documented


and


(Calvert


& Numbers


suggestions

Silverman,


Levitt


for

1983;


Stromberg,


remediation,


Gold,

1983;


are


1980;

Levitt,


McGarr,


research


& Geffner


available


, 1987


on the


Monsen


, 1983)


effects


There


acquired


ess


hearing


loss


the


post


-lingual


deaf


population


, according


Seyfried e

anecdotal.

production


t al. (1989)


There


much


is great


that


variability


post-lingually


deaf


reported


the


population.


generally


speech


Thi


variability


view


has


that


been


reflected


adventitious


the


deafness


literature,


does


not


including


necessarily


result


disordered


Z immermann


and


speech


(Goehl


Rettaliata


(1981)


& Kaufman,


compared


1984)

the


articulatory


patterns


an adventitiously


deafened


adult










to include


the


frequencies.


The


hearing


loss


reportedly


occurred


between


early


and


late


adolescence


and


was


unknown


origin.


The


subject


s hearing


loss


stabilized


around


age


26 and


he referred


himself


a university


speech


and

his


hearing

speech.


clinic


that


the

time


age


27 because


audiometric


test


concern


results


about


indicated


that


he had


a profound


sensorineural


hearing


loss,


however,


an informal


assessment


of his


speech


the


conclusion


that


speech


therapy


was


not


needed.


the


age


of 32


the


subject


again


sought


an evaluation


of his


speech


voice


production.


Although


speech


exhibited


some


deviations,


the


overall


interpretation


the


results


was


that


there


were


perceptual


phonemic


findings


during


the


speech


tasks"


170) .


the


time


this


study,


an informal


assessment


subject


s speech


two


trained


listeners


judged


the


subject


utterances


to be phonemically


accurate.


The


speech


task


the


subject


was


[bib],


[bab]


, [si],


[bar],


[rab]


the


carrier


phrase,


"That


s a


" (p


. 170)


Articulatory


patterns


the


subject


were


recorded


using


high


speed


cinefluorography


and


compared


with


normal


hearing


control.


The


speech


productions


of the


deaf


subj ect


revealed


systematic


timing


differences


the










coordination


the


tongue


dorsum


with


other


structures,


consistently


late


voice


termination


compared


with


normal


control.


The


authors


suggested


that


speech


a deaf


individual


acquired


slowly


because


of overlearned


motor


patterns.


Exceeding


normal


variability


ranges


these


patterns


must


occur


repeatedly,


without


the


speaker


reali


zing


the


error,


degeneration


in speech


patterns


occur


They


concluded


that


auditory


information


"plays


a critical


role


the


long


term


monitoring


maintenance


coordinative


structures


(mainly


involving


the


tongue


dorsum


musculature)


speech"


177).


Cowie


et al. (1982


studied


twelve


post


-lingually


deafened


adults


Northern


Ireland


their


subjects


were


class


ified


as having


profound,


bilateral


sensorineural


hearing


loss,


with


exception


one


subject


who


had


some


hearing


in one


ear


but


was


losing


The


purposes


their


study


were


analyze


articulation


errors


, (2)


provide


useful


measurements


subject


intelligibility


, and


identify


problems,


other


than


intelligibility,


that


subjects


reported.


Tape


recordings


hearing


-impaired


subj ects


reading


five


short


passages


conversing,


singly










listen


to each


hearing-impaired


subject' s


recording.


Speech


intelligibility


was


measured


using


a "shadow


technique.


This


technique


involved


normal


hearing


subjects


stening


the


taped


recordings


and


attempting


to repeat,


verbatim,


what


was


said


as it


was


being


said.


The


percentage


of correctly


intelligibility.


The


repeated


authors


words


listed


was


the


the


measure


following


caveat


regarding


the


level


of information


provided


this


technique:


is a relative


measure


intelligibility;


the


results


identify


cut-off


points


between


subjects

hearing;


with

and


intelligibility


measurements


problems


using


and


this


those


technique


with

e are


normal

not


directly


comparable


to studies


the


pre-lingually


deaf.


Despite

suggest


the

two


above 1

points:


.imitations,


most


the

of th


results ob

e subjects


tainted

had m


did


easurable


losses


intelligibility;


there


was


variability


among


subjects.


General


factors


affecting


subjects


pertained


style


and


content


the


reading


passage


which


the


simpler


the


style,


and


more


familiar


the


topic,


the


higher


the


intelligibility


scores;


and


age


at onset


deafness


seemed


to have


greatest


effect


intelligibility


with


worse


speakers


becoming


deaf


before


years


age


best


speakers


becoming










can


made.


The


authors


also


noted


that


their


data


did


suggest


that


factors


such


as social


background,


intelligence


or motivation


were


relevant.


Other


problems


related


to speech


deterioration


were


explored


this


study


evaluating


normal-hearing


listener


s responses


speech


of eight


original


twelve


deaf


subjects.


subject


listening


to the


deaf


speakers


reported


that


they


would


have


problems


understanding


their


speech.


but


one


the


listeners


reported


that


they


would


keep


conversation


with


the


deaf


speaker


as brief


as possible.


In addition


these


findings


illustrated


the


tendency


of people


to associate


characteristics


of speech


with


characteristics


of speakers.


example,


a speaker


with


a harsh


vocal


quality


was


viewed


"unfriendly"


108) .


The


authors


concluded


that


these


findings


suggest


that


post-lingually


deaf


individuals


experience


some


degree


speech


deterioration


but


there


wide


deafness


appeared


this


to be


population,

a relevant f


and


'actor


in the


level


deterioration.


The


significant


speech


deterioration


many


the


subjects


illustrated


the


need


more


attention


speech


conservation


this


population,


to enable


them


function


the


hearing


world.


variability


at onset










areas:


phonetic


errors


spontaneous


read


speech;


intelligibility


ratings


errors


normal-hearing


using mo

listeners


nosyllabic


words;


subject


and


s speech


production


at 2


months


30 months


following


onset


deafness.


Analysis


of phonetic


transcriptions


revealed


omissions


to be


most


prominent


error;


specifically


the


phonemes


and


/t/.


Some


these


instances


were


attributed


normal


colloquial


usage


such


as the


word


"and"


being


shortened


to "an.


Of 69 omissions,


were


alveolars


The


author


suggested


that


audition


may


very


important


maintenance


these


sounds


due


their


weak


tactile


cues.


Vowel


quality


findings


differed


from


the


read


spontaneous


speech


samples


with


spontaneous


sample


yielding

readers.


more

This


instances


was


of schwa


attributed


that

the


normal


subj ect


hearing


s exaggerated


care


and


precision


while


reading


"leading


to a highly


artificial


sample"


40).


The


suprasegmental


features


of speech


were


found


show


deviations


from


norm


also.


The


deviations


noted


were:


inability


control


pitch;


production


of all


syllables


with


equal


stress;


and


slower


than


normal


rate


/ d/










listeners.


The


listeners


gave


written


responses


what


they


heard


and


these


responses


were


recorded


on confusion


matrices


initial


consonants,


vowels,


and


final


consonants.


Initial


consonant


errors


represented


presentations


and


those


errors


affricates


were


most


commonly


misunderstood


(21%).


Additional


analysis


affricates


revealed


that


the


voiceless


affricate


(/tf/)


accounted


errors


In addition,


of those


errors,


over


involved


substituting


the


consonantal


blend


/tr/


/t/. .


The


voiced


affricate


(/dg/)


yielded


an error


rate


of 12%


presentations


and


almost


those


errors


involved


substitution


the


blend


/dr/


for


The


author


suggested


that


relatively


weak


tactile


cues


the


release


phase


the


affricates


necessitates


auditory


monitoring


to maintain


correct


production.


Analysis


vowel


and


diphthong


errors


indicated


confusion


with


adjacent


vowels,


suggesting


"overlapping"


formant


values


45) .


This


was


further


supported


the


number


errors


between


vowels


with


similar


values


which


was


explained


the


fact


that


the


are


more


distorted


and


the


subject'


knowledge,


or memory,


tongue


placement


had


been


adversely


affected


the


hearing


loss.


This


view


was


further


supported


evidence


that


more


diphthongs


were


/ d3 /










"perceived


as steady

Conversely


state

, the


rather than

vowels were


dynamic

correctly


movements"

perceived


steady


state.


The


greatest


number


consonant


errors


involved


place


articulation.


These


findings


agree


with


those


Z immermann


and


Rettaliata


(1981)


and


further


support


importance


of audition


production


of closing


gestures


speech.


Without


synchronous


and


correct


articulatory


patterns


there


may


"blurring"


of place


cues


(Plant,


1984).


The


three


final


area


spontaneous


investigation


speech


samples,


involved


recorded


presenting


deaf


subject


at approximately


months


and


months


after


onset


deafness,


twelve


normal-hearing


listeners


listeners

pitch, in

month int


were


tonatio

erval,


asked


to rate


rate.


post-onset,


the

Th

was


samples on voice

recording made


rated


near


normal,


quality,


whereas


recordings


at 30 months,


post-onset,


was


rated


abnormal.


The


parameters


rated


most


deviant


were


pitch


and


intonation.


The


above


research


delineated


errors


in speech


production


which


authors


attributed


directly


adventitious


profound


hearing


loss.


Goehl


and


Kaufman










years


0 months)


the


time


hearing


was


lost.


They


emphasized


that


onset


of deafness


resulted


in an


interruption


the


maturation


child


s phonologic


system.


learn


They


speech,


speculated


auditorily,


that


from


this


inability


others


would


continue


account


speech


deterioration


would


important


as loss


auditory


feedback.


They


further


questioned


the


influence


speech


training


techniques


were


techniques


used


described)


with

and f


the


inall


child

v the


(these

possible


continuing


residual


effects


from


the


etiology


of the


hearing


loss


(meningitis).


These


authors


also


raise


questions


regarding


Z immermann


and


Rettaliata


(1981)


interpretation


their


data.


They


noted


that


these


authors


pointed


out


inability


generalize


their


findings


due


sample


size


= 2)


considerable


variability


in speech


production


across


speakers


regardless


their


ability


hear


or not.


addition,


they


questioned


whether


the


differences


between


the


hearing


and


deaf


subjects


were


real


differences


because


the


limitations


of describing


the


utterances


being


judged


as phonemicallyy


accurate"


170)


two


trained


listeners,


i.e.,


no formal


clinical


assessment


was


made


subjects'


speech


prior


their


experiment.













certified


speech-language


pathologists


as judges


determine


there


were


identifiable


changes


the


speech


of normal

addressed


hearing


the


and

study


deaf

were


subj ects.

whether


The

those


specific

expert 1


questions


isteners


would


able


"(1)


judge


articulation


as within


normal


limits,


and


identify


speakers


as being


adventitiously


deafened"


The


subjects


were


divided


into


two


groups,


deaf


hearing


were


matched


sex


and


were


similar


(range


years


old)


The


deaf


group


was


selected


from


a pool


twelve


who


were


attending


a speechreading


group


results


the


they


time


were


study


expected


Based


to develop


on their


"speech


audiometric


deviations"


due


their


degree


hearing


oss


(Calvert,


1982)


The


control


group


, based


on audiometri


evaluation,


was


determined


to have


normal


(for


level)


hearing.


Each


subject


was


taped


reading


the


Grandfather


Passage.


The


passages


were


randomized


the


order


presentation


was


reversed


every


other


judge.


The


second


question


identification


of deaf


speakers)


was


always


presented


after


the


first


, identification


normal


articula-


tion)


order


to prevent


listener


bias.


was


also


done


to give


the


listener


unlimited


trials


order


to make


.e.










The


results


indicated


that


subjects


were


judged


to have


normal


articulation,


but


that


deafened


speakers


could


be identified


at better


than


chance


level.


In addition


neither


number


years


since


onset


deafness


nor


the


degree


of impairment


seemed


related


to the


listener's

reported t

describing


labeling


hat

the


speaker


a review of

speech of


the

those


as deaf.


comments

subj ects


The


the


authors

judges


identified


as "deaf"


included


differences


rhythm


, rate,


voice


quality,


and


"slightly


inaccurate


articulation"


particularly


regard


sibilants


63) .


Goehl


Kaufman


suggested


that


these


findings


may


be supported


Z immermann


and


Rettaliata


(1981);


judges


however,


their


they


study


also


pointed


misidentified


that


some


some


normal


subjects.


They


also


point


out


the


possible


influence


the


expectations


which


judges


brought


their


task


once


they


knew


that


the


subjects


were


deaf.


These


expectations


were


described


as a willingness


on the


part


the


judges


tolerate


mild


changes


speech


that


are


associated


with


elderly


population


(rate,


voice,


articulation)


and


still


conclude


that


speech


production


was


within


normal


limits.


Goehl


and


Kaufman


concluded


that


clinically


significant


speech


production


deterioration,


as a result


of adventitious










maintaining


speech


based


on a servo-mechanism


theory


speech


control


was


also


supported


their


study.


Acquired


hearing


loss


produces


variable


effects


on the


speech


of post-lingually


deafened


adults.


The


loss


auditory


monitoring


capabilities


has


been


the


attributing


cause


of speech


deterioration


some


this


population


(Cowie


et al.,


1982


Plant,


1984;


Zimmermann


& Rettaliata,


1981)


A dissenting


view


was


reported


Goehl


and


Kaufman


(1984).


Finally,


need


more


research


this


area


apparent


due


to the


lack


of conclusive


empirical


studies


(Seyfried


et al.,


1989).


Cochlear


Implants


Cochlear


implants


are


surgically


implanted


devices


that


directly


stimulate


inner


ear


and


produce


a sensation


sound


The


Committee


on Cochlear


Implants


(Hopkins,


1986)


listed


eleven


different


types


implants


which


are


being


manufactured


United


States


or Europe;


however,


Gibson


(1987)


wrote


that


there


are


reportedly


over


different


cochlear


implant


devices


being


investigated


worldwide


Despite


number


of implants


being


investigated,


their


basic


composition


remains


the


same:


microphone;


oDeech


processor: (3


transmitter


ccii r


r~rni varP


... J


,










Differences


in Cochlear


Implants


The


differences


in cochlear


implants


can


be described


examining


electrodes


following


electrode


features


position;


number


speech


processing


strategy.


The


employed

(House,


earliest


today

1976) .


simple


had a single

Some example


cochlear


electrode


of multi


implant


"single


-electrode,


still


Lannel")

or "multi-


channel"


implants


cited


Gibson


(1987)


and


the


Ad Hoc


Committee


(Hopkins


, 1986)


included


the


Symbion


channels


Chorimac


channel


and


Nucleus


channel


devices.


The


configuration


electrodes


multichannel


devi


ces


differ,


but


subjects


study


will


wearing


Nucleus


device,


a description


electrode


configuration


will


be given


in more


detail


later


the


chapter.


The


second


difference


cochlear


implants


the


electrode


sitioning.


An extracochlear


electrode


may


placed


on the


membrane


the


round


window;


type


being


investigated


Hochmair


(#M/Vienna


implant)


Fraser


(Finetech/RNID)


as cit


ed by


Gibson


(1987)


Example


intracochlear


devi


ces


include


Symbion,


the


Chorimac,


Nucleus


(Gib


son,


1987)










filtered between


2700


(Boothroyd,


1989).


This


filtered signal


used


to vary the amplitude of


a 16 KHz


sinusoidal


carrier


signal


which


just below


audibility.


There


no other processing


after the


amplitude modulation.


The clinician


is able


to adjust


carrier


level


and


limit


the maximum output


through


manipulation of


processor


controls


each


patient.


Limiting


of the maximum output


by peak clipping.


Moore


(as cited by

processing as


Kessler,


1989),


referred to this


"modulated-carrier,


analog


type of

approach,


defining


it as a


strategy


in which


the waveform itself


used to drive


the electrode and


in which an attempt


is made


to squeeze the entire speech signal


into a single channel"


188).


Another type of


speech


processing,


and


the one used by


the Nucleus device,


selectively


extracts components of


speech


from the acoustic signal.


The directional


microphone


picks up sounds and sends the


information


the speech


processor.

extracts f


The speech


* aan


processor


information


filters


from the


the


sound and


speech signal.


That


information passes


to a


"map"


which


the digital


memory


the speech processor


electrode,


here


current amplitude,


that


and stimulus


the appropriate


rate are










signal,


allowing


pairs


the


electrodes


to be stimulated


to produce


speech


-like


sounds.


The


Nucleus


device


extracts


fundamental


frequency


(FO)


from


speech


person


and


sends


that


information


speaker


intensity


rate


information


of stimulation


is conveyed


Signal


amplitude


ses.


First


(Fl)


and


second


formant


information


provided


from


position


the


electrodes.


Initially,


the


Wearable


Speech


Processor


(WSPII)


provided


only


FO and


information.


In 1985,


another


coding


strategy


(WSPIII)


providing


Seligman,


basal


FOF1F2


Blamey


electrode


information


& Clark,


was


became


available


1987)


stimulated


followed


coding

rapid


(Dowell,


strategy


succession


stimulation


a more


apical


electrode


yielding


and


cues,


respectively


The


addition


of F1


the


processing


strategy


perception


would


expected


as those


formants


to further


are


enhance


known


vowel


critic


(MacKay,


1987)


The


most


recent


development


coding


strategy


became


available


1989


with


the


Mini


Speech


Processor


(MSP)


(Skinner,


Holden


, Dowell,


Seligman,


Brimacombe,


Beiter,


1991


Clark


1991)


The


MSP


employs


"multi-peak"


strategy


which


measures


dominant


spectral


peaks


frequency


ranges


containing


270-730


and


(840-










addition three other frequency bands can be activated A3


(2000-2800 Hz),


(2800-4000


Hz),


and A5


(4000-7000 Hz)


(Patrick &


Clark,


1991).


and A2


are always


activated and


activation of


the higher


frequency bands


is dependent upon


the particular acoustic signal


being


sampled.


In the case


of unvoiced stimuli


there


is a


small


amount of


energy


in the


frequency range


so the


electrode


not


stimulated.


band


In its


is activated


place


thereby


fixed electrode


extracting high


for the A5


frequency


information


(Clark,


1991) .


The opposite


true


for voiced


stimuli.


Since


there


is only


a small


amount of high


frequency energy


7000


in voiced stimuli


not activated.


the A5 electrode


The ability


(4000-


of the speech


processor to provide


combination with FOF1F2


consonant


frequency bands A3,


information provides more vowel


information.


In addition


to extracting


information


important


understanding


designed to


speech.


The electrode configuration


take advantage of the physiological


response of


the cochlea.


This


is accomplished by


stimulating discrete


areas of the basilar membrane.


The configuration


described as


"bipolar.


Bipolar electrodes


are


small


are


located at equal


distances


from the target nerve and










electrodes


stimulate


large


groups


nerve


cells


and


are


effective


providing


discrete


areas


of stimulation


(Fravel,


1986).


The


design


Nucleus


implant,


using


bipolar


electrode


configuration,


takes


advantage


place

the h


pitch


igh


theory


frequencies


f hearing.

necessary


For

for


example,


stimulation


perception


can


accomplished


because


number


of electrodes


and


fact


that


high


frequency


information


coded


on the


basis


of place


on the


basilar


membrane.


In contrast,


the


frequency

electrode


information

at a rate D


found


roportional


used

the v


to stimulate


oicing


each


frequency


(Clark,


1986).


This


is consistent


with


what


known


about


frequency


hearing


which


coded


based


on the


"place


maximal,


discharge


periodicity


the


discharge


pattern....


" (Yost,


1985,


92-93).


Patient


Selection


Criteria


There


has


been


a wide


range


selection


criteria


and


large


variations


in patients'


responses


as more


people


have


received


devi


ces.


the


present


time


there


are


standardized


implant


criteria


candidate


accepting


(Goldstein


or rejecting


Friedelwald,


1988)


a cochlear

Maddox


and


Porter


(1983)


have


suggested


that


rather


than


asking,


"Who


is a candidate


a cochlear


implant?"


would


r.


u


G


LV.










basis and should not be generalized


the profoundly


deafened population as a

The criteria suggest


whole"


250).


ted by the National


Institutes of


Health


Consensus


Development


Conference Statement


(1988)


include


following:


Audiolocical


Criteria:


Bilateral,


profound sensorineural


hearing


loss


Bilateral,


aided


thresholds greater than


dB HL


0 percent correct on


open-set speech


recognition


Lack


substantial


increase


lipreading


with appropriate amplification


Electrophvsioloqical


Criteria:


Measurement of


early,


middle,


and late


latency


evoked potentials


Absence of neural


responses may


or may not


prove


to be a


contraindication


Medical Surqical


Criteria:


Usual


candidate


is a


postlingual


onset,


healthy


adult


Possible complicating factors


include:










Psychouhvsical


Criteria:


None


psychophysical


data


available,


example


gap


detection,


are


considered


critical


issue


of candidacy


this


time


Psychophy


sical


data


have


been


shown


good


predi


ctors


of speech


recognition


performance


Psvcholog ical


and


Linguistic


Criteria:


Most


psychological


exclusionary


purposes


testing


such


done


as mental


retardation


or psychiatric


disorders


Risks


and


Benefits


Cochlear


Implants


As with


any


surgical


procedure


and


use


general


anesthesia,


risks


there


cited


are


the


inherent


Hoc


risks


Committee


the


Report


patient.


(Hopkins,


The


1986)


include:


The


reduction


or total


loss


on any


presurgical


residual


hearing


Complications


due


to anesthesia


surgery


Post-surgical


sks:


Bioincompatibility


internal


components










Facial


nerve


damage/paralysis


New


bone


growth


within


cochlea


Intracochlear


scarring


and


fibrous


tissue


growth


Degeneration


Unknown


of surviving


reactions


nerve


to prolonged


fibers

electrical


stimulation


Required


replacement


of failed


internal


components


Unrealistic

patients and


expectations


family


leading


of cochlear


implant


to psychological


disturbances


Possible

Possible


vestibular c

exacerbation


complications


tinnitus


Possible


benefits


cited


committee


include:


Increased


awareness


of sound


improved


ability


to monitor


speech


production


Recognition

Improved aw


some


areness


everyday


sounds


of surprasegmental


features


speech


Supplement


to lipreading


Perception

leading to


some


limited


segmental


word


aspects


recognition


of speech

and










improved


social


interaction


and


employment


potential


Significant


word


recognition


sentences


sound-alone


Rehabilitation


conditions


Issues


Aural


rehabilitation


cochlear


implant


patient


begins


with


evaluation


procedures


employed


during


selection


process.


Lansing


(1988)


has


divided


the


rehabilitation


process


into


three


areas:


development


realistic


expectations


implant;


training


the


interpretation


and


use


new


auditory


information


with


without


visual


cues;


development


coping


strategies


to enhance


communication.


Some


variability


responses


from


patients,


no doubt,


due


their


individual


differences


however,


some


may


be due


differences


protocol


among


the


centers.


While


most


centers

direct


offer c

training


counseling


and


measures


, ongoing


adjustment


of performance,


others


device,

only


provide


counseling


and


adjustment


the


implant


(Hopkins,


1986).


Others,


like


House


Ear


Institute


and


centers


implanting


Nucleus


devices


have


specified


extensive


protocols


adiustina


implant


and t


rainina


~ral


. ..


L.


. .


1IC










Soeech


Perception


Studies


Cochlear


Irnolant


Users


Speech


perception


studies


with


the


implant,


including


both


single


multi-channel


have


been


an area


of wide


interest


to the


resea


community


(Bilger,


1983


Eddington,


1988


Eisenberg,


et al


1983


Holmes


, Kemker,


& Merwin,


1987)


The


perception


of speech


using


auditory


cues


only


been


seen


some


patients


and


recently


been


reported


House


(1989)


children


some


children.


evaluated


over


Berliner,


50 profoundly


years.


Tonokawa,


hearing


All


Dye,


-impaired


the children


were


implanted


with


the


3M/House


single-channel


devi


ce.


Their


ages


the


time


study


ranged


from


to 15.9


years,


with


average


age


the


onset


of deafness


of 2


years.


Age


the


time


receiving


implant


ranged


from


to 15


years


, with


a mean


of 6.2


years.


Test


materials


were


administered


level


using


Portions


live-voi


at a normal


Glendonald


Auditory


conversation


Screening


Procedure


(GASP)


(Erber,


1982


were


administered


assess


open


-set


speech


recognition.


The


authors


noted


that


GASP


designed


as a closed


-set


test


, picture


pointing


task;


however,


study


was


administered


auditorily

sentence s


only


timuli


The children


using


were


an auditory


tested


mode


with


only


word


They


and

reported










deafness


was


noted


to be


shorter


children


able


score


on the


open-set


discrimination


task


than


those


who


were


unable


to do


SO.


Berliner,


et al.


(1989)


also


cited


a study


Geers


and


Moog


press


which


they


assessed


of 12


high-performing


children


using


3M/House


device,


they


also


reported


that


children


study


achieved


some


open-set,


auditory-only


recognition


simple


sentences.


Dorman


et al.


1989)


investigated


the


ability


patients


using


Symbion


multi


-channel


implant


to identify


synthetic


vowels.


at least


Eight


years


subj ects


old.


The


participated


length


deafness


the


study,


ranged


from


year


to 28


years


with


a mean


of 6


years.


The


results


this


study


indicated


that


eight


subjects


scored


above


70 percent


correct


on a test


of spondee


word


identification.


Twelve


synthetic


vowels


the


"bvt"


format


comprised


stimuli.


Vowels


characterized


F1 and


formants


were


well


identified


whereas


those


with


high


formants


were


well


identified.


The


authors


concluded


that


their


results


were


consistent


with


the


model


Fl being


specified


a rate


code


and


extreme


values


specified


rate/place


code.


Waltzman


and


Hochberg


(1990)


investigated










age


Speech


from


Pattern


26 to 85,


with


Contrast


a mean


(SPAC)


test


of 51


years.


(Boothroyd,


The


1987)


was


used


to evaluate


perception


of speech


pattern


contrasts


the


subjects.


This


test


evaluates


the


perception


of four


suprasegmental


eight


segmental


speech


contrasts.


a forced


-choice


format


using


real


words,


phrases,


sentences.


The


results


of this


investigation


indicated


that


both


processing


strategies


provided


suffi


cient


information


about


speech


contrasts;


especially,


fundamental


frequency


temporal,


and


intensity


cues.


Lastly,


Tye-Murray


Tyler


(1989)


investigated


auditory


consonant


and


word


recognition


skill


subjects

implants


seven


wore

n wor


3M/House

e Nucleus


implants,

implants


three

and


wore


wor


3M/Vienna

e Symbion


implants


The


speech


material


consisted


of 14


consonants


in an /


context


Sentence


Test


Without


Version


(Tyler,


Lansing


, & Preece,


1984)


Their


conclusions


were


follows


Most


subjects


recognized


consonants


in an


audition-only


condition


at above


chance


level


Subjects


perceive


the


envelope


feature


relatively


well

The


and

voic


the


ing,


ace


feature


nasality,


relatively


duration,


and


poorly.

envelope











Most


multi-channel


users


achieved


some


open-set


word


recognition


an auditron-only


mode,


there


was


wide


range


of performance.


None


3M/House


or 3M/Vienna


users


achieve


open-set


word


recognition.


Subjects


who


are


able


to utilize


middle


high


frequency


information


are


more


likely


score


better


on open-set


sentence


tests.


Speech


Production


Cochlear


Imolant


Patients


The


speech


production


of cochlear


implant


patients


been


investigated


as thoroughly


as speech


perception.


As stated


introduction,


the


device


seems


to offer


benefit


as evidenced


reported


improvement


loudness


control


and


vocal


quality.


Those


improvements


have


been


attributed


the


re-establishment


the


auditory


feedback


channel


(Chouard,


et al.,


1983;


Engelmann


et al.,


1981


Fourcin


et al.,


1983).


One


study


designed


specifically


to investigate


the


effect


single


channel


cochlear


implant


on voice


parameters


was


reported


Kirk


and


Edgerton


(1983).


The


subjects


were


two


men


two


women,


ages


to 65


years.


Speech


samples


subjects


reading


the


Rainbow


Passaae


vti~h Iba


i4mnrl nn+


al.*$ A f lat'


A-- -rA~~ Y


CYIAI~


A--_ _


hR dldrd


--~-


~~A


i


nT~ 31111










These


changes


were


direction


the


normal-hearing


controls.


The


female


subjects


produced


voices


that


were


higher


than


when


implant


was


turned


off.


Again,


this


finding


was


direction


the


normal-hearing


control


speakers.


subj ects


continued


demonstrate


prolongation


sentences


and


pauses


consistent


with


the


speech


deaf


even


when


the


implant


turned


In conclusion,


authors


cited


need


further


study


this


area.


Speech


production


output


three,


post-lingual,


Nucleus,


22-channel


implant


users


was


reported


Medwetsky,


Hanin,


Boothroyd


(1987)


Their


subjects


had


been


j udged


as successful


implant


users


based


on their


speech


recognition

excellent s


ability,


sentence


with


per


only


ception


the

using


implant,


and


implant


their

with


lipreading.


Their


subj ects


had


become


deaf


the


ages


, 18,


and


years,


respectively.


They


had


received


their


implants


ages


, 38,


respectively.


The


purpose


the


study


was


to evaluate


their


pre-


and


post-implant


speech


production


as defined


intelligibility.


Boothroyd'


Speech


Perception


Contrast


(SPAC)


test


was


used


measure


intelligibility


of phonetic


contrasts.


While


the


test


was


originally


designed


measure


speech










three


subjects


twice.


A pre-implant


recording


was


initially


made


and


months


after


implantation


a second


recording


was


obtained.


The


subjects


did


receive


any


speech


therapy


during


interval


between


receiving


implant


and


making


the


second


recording.


Twelve


normal-hearing


listeners


were


presented


the


recordings


of each


implant


user


and


they


gave


written


responses


to what


they


heard.


The


results


obtained


indicated


that


there


were


significant


improvements


production


Speech


Pattern


Contrasts


three


subjects.


These


improvements


were


mostly


voicing,


stress,


and


intonation.


was


suggested


that


these im

provided


provements


were


implant.


due


the


Two


auditory


the


subject


feedback

s also


demonstrated


significant


improvement


phoneme


and


word


production.


Oster


ten


3M/Vien


(1988)


re


post-lingual

na extracochl


ported

Swedish


ear


changes


patients


the

who


single-channel


speech

received


device.


production

the


The


research


was


conducted


after


18-24 months


implant


use.


The


patients


had


varying


causes


hearing


loss


and


their


ages


ranged


from


25-55


years


old.


Recordings


were


made


subjects


' reading


"standard


passage


words"


15) .


The


subjects


read


prior


to receiving


the


implant


one,










normal


limits


appropriate


pitch


prior


to receiving


implant.


However,


any


changes


noted


post-implant


were


reportedly

as evidence


towards

that s


normal


subjects


are


ranges.


able


This


to make


was

use


interpreted

of low


frequency


information


received


through


auditory


feedback


order


to control


monitor


their


pitch.


Those


subj ects


whose


pre-implant


voices


had


been


described


as tense


harsh


were


reported


to exhibit


improved


voice


quality


following


implantation.


Subjects


relatives


responded


a subjective


questionnaire


assess


the


perceived


benefit


of the


implant.


the


subjects


reported


feeling


more


confident


their


communication


following


receiving


their


implant.


Lastly,


was


used


at durations


of 200-600


milliseconds


to attempt


to determine


the feedback


provided


with


implant.


Responses


reported


the


literature


normal-hearing


individuals


.e.,


slow


speech,


repetitions


or words


or syllable


higher


intensity,


and


increase


pitch")


were


not


found


these


subjects.


Two


explanations


were


offered


this


lack


response:


years


total


deafness


had


resulted


patients


learning


to rely


tactile


feedback,


FO and


durational


auditory


cues


are


perceived


as background


noise


and


do not


influence


articulation.










hearing


their


own


voice.


Normally,


as people


speak,


they


hear


their


own


voices


within


approximately


one


millisecond


(Yates,


1963).


Lee


(1950)


first


described


a condition


DAF


which


produced


changes


speech


production


some


individual


He reported


that


his


subjects


read


"moderately


difficult


text


at a comfortable


speed....


While


under


different


conditions


of DAF.


The


changes


noted


their


speech


included


a slower


rate


and


stuttering


characterized


repetition


syllables


or fricativeq.


suggested


finding


a model


describing


speech


production


a closed-loop


to explain


system


which


this

h the


length


of each


loop


was


approximately


proportional


the


time


necessary


particular


function.


He defined


four


loops,


arranged


a hierarchy


, made


articulatory


loop


(phonemes),


a voice


loop


(syllables),


a word


look,


and


a thought


loop.


He proposed


that


the


auditory


system


was


series


with


the


voice


loop


auditory


monitoring


and


that


the


articulatory


and


voice


loops


were


most


affected


DAF.


stressed


that


loop


the


the


model,


auditory


down


monitor


syllable


dissatisfied


level,


with


may


the


be repeated


previous


performance.


Further,


there


was


a common


junction


the


loops


which


was


represented


a cortical


speech


*










Fairbanks


(1954)


proposed


a more


elaborate


closed-loop


model,


or servosystem,


speech


production


based


auditory


utilizing


monitoring


DAF.


illustrated


model


his


included


model


sensor


with


unit"


studies


which


auditory,


tactile,


and


proprioceptive


information


back


the


"comparator


unit.


This


information


was


compared


output


and


comparator


identified


any


discrepancies


between


the


two


signals.


He noted


that


the


delayed


auditory


feedback


condition


sin forms"


system


about


success


effecting


and


ordering


intended


output


units,


thus


impairing


basic


produce"


334).


In 1955


, Fairbanks


reported


on the


articulation


errors


and


changes


the


rate


of speech


his


subjects


under


DAF


condition.


Subjects


this


study


were


sixteen


male


college


students


who


had


never


experienced


DAF.


They


read


the


Rainbow


Passage


under


five


different


stimulus


conditions


with


speech


output


amplified


a constant


amount


and


the


delay


intervals


varied


from


to 800


milliseconds.


Results


indicated


that


DAF


resulted


a variety


speech


disturbances


divided


into


groups:


"direct


effects"


and


"indirect


effects.


Direct


effects


included


an increase


articulatory


errors


and


longer


duration


and


indirect


effects


included


an increase


in sound


pressure,


.e.,


increased










The


data


were


from


subjects


the


1955


study


of sixteen


male


college


students


and


the


various


types


errors


found


the


original


study


were


investigated.


Their


analysis


indicated


that


there


was


agreement


with


original


study,


the


general


effect


of DAF


to a reduction


number


correct


words


read


an increase


the


total


time


reading.


They


also


noted


that


the


maximum


effect


was


seen


using


a 200


milli


second


delay.


articulatory


errors


reported


included


substitutions,


omissions,


were


and


additions


additions.


and


The


about


greatest


those


number


were


errors


repetitive.


The


authors


noted


that


repetitions


were


not


primarily


corrective


but


rather


a purposeless


response.


The


amount


delay


which


is most


disruptive


has


been


shown


vary


as a function


with


the


delay


necessary


to disrupt


speech


ecreas


with


age


(MacKay,


1968


Siegel,


Fenst,


1951;


Garber,


Fairbanks,


Harrington,


& Pick


1955


have


1988)


, 1980).


MacKay,


reported


Many


1968


that


researchers


Buxton,


between


(Black,


1969


and


milliseconds


produces


most


disruption


the


speech


adults,


with


exception


of older


adults


years


old)


who


experience


maximal


disruption


their


speech


milliseconds


(Buxton,


1969).


.e.










Timmons


& Boudreau,


1972),


however,


Buxton


(1969)


reported


no differences.


The


demonstrated


effect


has


been


interpreted


many


researchers


as evidence


that


speech


acts


as a


servomechanism


and


auditory


feedback


the


primary


control


channel


(Borden


& Harris,


1984).


However,


Borden


and


Harris


(1984)


also


noted


that


view


been


challenged


those


who


point


out


that


DAF


effect


can,


example,


overridden


speaker


attends


the


reading


and


ignores


the


acoustic


information


being


received.


In addition,


measures


other


than


will


interfere


with


speech


production,


example,


amplifying


air


conducted


sound


will


cause


speakers


to decrease


their


vocal


intensity


(Siegel


& Pick,


1974),


attenuating


the


air


conducted


sound


will


produce


to hear


their


the


opposite


speech


at all


effect

they


and

will


listeners


Increase


are


their


unable

vocal


intensity


and


prolong


voicing


(Lane


& Tranel,


1971).


Finally,


Borden


and


Harris


(1984)


suggested


that


audition


a feedback


mechanism


monitoring


ongoing


fluent


speech


production


does


provide


a complete


explanation


"because


many


transient


sounds


provides


information


speaker


too


late;


he has


already


spoken


and


can


only


make


corrections


after


fact"


136) .


However,


there


was










with


auditory


feedback


they


will


try


overcome


attempting


to correct


their


speech


output.


Harrington


(1988


offered


another


model


to explain


effect


including


influence


of rhythmic


structure


the


production


literature


addressing


fluent

the a


speech.


acoustic


He noted


and


that


articulatory


the

aspects


of coarticulation


suggested


that


consonants


and


vowel


are


produced

overlap


using


time


"prespeci fies


"separate


the


articulatory


He stated

intervals


that r

between


strategies


hythmic

vowels


that


structure


stressed


syllables"


and


that


same


structure


allows


the


speaker


predict


when


vowels


of stressed


syllables


will


be auditorily


perceived.


illustrated


his


model


describing


production


two


syllables,


Sl and


, by


a fluent


speaker


under


DAF.


The


time


of production


the


vowel


would


some


arbitrary


unit


of time


after


vowel


of S1 and


amount


of DAF


was


milliseconds.


He suggested


that


the


effect


produces


a mismatch


between


the


"actual


time


production


of the


vowel


of S2


and


the


expected


time


perception"


39) .


The


speaker'


attempt


to correct


the


mismatch


results


an effort


onset


to study


of dysfluent


auditory


reliance


speech.


, Maxon,


Brackett,


Riordan,


Pfeffer


(1987)


studied


the


effect











oral/aural


educational


programs.


The


authors


reported


that


their


subj ects


displayed


disturbances


in their


speech


production


under


which


were


similar


to those


reported


literature


normal


hearing


individuals,


i.e.,


increase


the


time


to read


passage


or reciting


note


numbers


an increase


in vocal


intensity.


Based


on their


results

impaired


they


interpreted


children


can


make


data


use


to suggest


of minimal


that


auditory


hearing-

cues


during


self-monitoring.


A review


of the


literature


indicates


that


while


there


may


be various


explanations


to explain


the


effect,


the


presence


an effect


is not


disputed.


The


literature


also


suggests


that


audition


influences


an individual


s fluent


speech


production.


Snmmarv


The


importance


auditory


feedback


to the


normal


acquisition


speech


and


language


is unquestioned.


However,


there


are


differing


views


as to its


degree


importance


the


maintenance


adventitiously


of normal


profoundly


speech


production


hearing-impaired


(Cowie


Douglas-Cowie,


Rettaliata,


1983;


1981).


Goehl


Many


Kaufman,


this


1984


population


Zimmerman

experience


ah-rn4 fi~ran* rwhn n na n-Aiin4~C 4 nnn.


r n eraaan


o i nn C f; ~P11C


rrh ~nna


mk,,,


CL *I~ 1)~1


i










amplification.


A cochlear


implant


the


only


type


device


available


which


has


capability


of providing


auditory


feedback


them.


Some


studies


of speech


perception


cochlear


implant


users


have


reported


improvement


loudness


control


and


voice


quality


and


have


attributed


improvement


to the


reestablished


auditory


feedback


(Chouard,


et al.,


1923


Engelmann


et al.,


1981


Fourcin


et al.,


1983).


The


area


of speech


production


adventitiously


deafened


cochlear


implant


user


has


been


extensively


studied.


an area


needing


further


study


document


effectiveness


reestablished


auditory


feedback


system


and


to begin


to evaluate


effectiveness.


Delayed


measures


auditory


the


feedback


cochlear


offers


implant


a tool


users


making


speech


objective


production


with


and


without


the


implant.















CHAPTER


METHODOLOGY


The

whether


procedures


there


this


is a delayed


study w

auditory


ere


designed


feedback


to ascertain


(DAF)


effect


speech


users.


production


Specifically,


of post-lingual


parameters


cochlear


measured


implant


evidence


of a DAF


effect


were:


reading


rate


as measured


total


time


to read


the


Grandfather


Passage,


speech


duration


measured


total


time


to count


backwards


from


and


(c3)


total


number


of consonant


and


vowel


errors


reading


and


counting


backwards.


The


cochlear


implant


users'


speech


was


recorded


presence


and


absence


of DAF


with


their


cochlear


implant


speech


processor


off


and


on.


addition,


using


a third


conventional


experimental c

amplification


condition


the


was


investigated


unimplanted


ear.


Subjects


Eight


subjects


participated


this


study--five


women


and


three


men.


All


had


completed


the


recommended


number


post-implant


aural


rehabilitation


sess


ions


and


were


wearing


the


Melbourne


(Cochlear


Corporation)


22 multichannel










subjects


ranged


age


from


years


with


a mean


of 47


years.


Reported


hearing


loss


etiologies


included


meningitis,


noise,


Meninere


s Syndrome


and


four


with


known


etiology.


suspected


to be


One

Cogan


these


unknown


s Syndrome.


etiologies


Unaided


pure


was

tone


averages


(500,


1000.


2000


the


better


ear


ranged


from


75 to 115+


HL with


a mean


of 102


dB HL.


The


duration


hearing


loss


the


subjects


ranged


from


to 41


years


with


a mean


of 20


years.


One


subject


wore


a hearing


aid


unimplanted


ear


no longer


wore


hearing


aids,


and


one


never


worn


one.


The


subjects


reported


having


worn


the


cochlear


implant


a minimum


of five


and


one-half


months


to a maximum


five


and


one-half


years.


Estimates


of daily


wearing


time


ranged


from


18 hours


a day,


with


a mean


wearing


time


of 13 hours


a day.


The


subjects


reported


having


worn


the


cochlear


implant


a minimum


five


and


one-half


years.


Estimates


of daily


wearing


time


ranged


from


18 hours


a day


with


a mean


wearing


time


13 hours


day.


Information


the


individual


subjects


summarized


Table


Test


Procedures


Preliminary


Procedure


After


the


subj ect


read


and


signed


informed


consent


consent












51







N
*u N
r C -



Cd) N

44 N N
N ~~~I 6 i
Ml N~ 0' *



I' Lw SD IA -




N
.c N '
A0

*I 0 0 CIo



3U N C
4' 63 4C N\ -


*, Le .'
Lu a- N N S -
I m01- '0 C


C
a-a



4' ND r

cu OO0. 0. N
z Ml 'S N N S K -





I C 4

U- a

~I -
** N

1O '0crO

V] u cnN










obtain


her


evaluation


of each


subjects


' family


support


system.


The


majority


subjects


reportedly


enjoyed


"good"


family


support


system.


To elicit


an objective


picture


the


subject


performance


using


the


implant,


each


was


given


subtests,


the


4-Choice


Spondee


Test


and


10 sentences


from


the


CID


Everyday


Sentence


Test,


from


The


Minimal


Auditory


Capabilities


Battery


(Owens,


Kessler,


Telleen,


Schubert,


1981).


These


materials


and


the


test


configuration


were


selected


based


on the


Cochlear


Corporation


test


protocol


individuals


receiving


their


device.


Scoring


both


tests


was


based


on a percentage


correct


score.


The


percentage


correct


score


sentences


was


based


on key


word


scoring


Both


tests


were


administered


using


only


auditory


cues


only


with


the


speech


processor


worn


at its


usual


setting.


The


tests


were


administered


a sound-treated


audiological


test


suite,


sound


field,


with


the


subject


facing


the


output


speaker


at a distance


one


meter.


The


material


was


presented


an intensity


70 dB SPL.


Results


these


tests


can


found


Table


To obtain


a subjective


estimate


of performance


using


the


implant,


the


subj ects


were


asked


to complete


Performance


Inventory


Profound


and


Severe Loss


(PIPSL)










Table


Percentage


Choice
Tests.


correct


Spondee


results


and


CID


obtained
Everyday


on the


Sentences


4-Choice Spondee CID Everyday Sentences*
Ss % Correct % Correct


1 90 22

2 100 53

3 100 30

4 100 75

5 60 31

6 100 67

7 70 3

8 100 1


* Ten


sentences


were


presented










profound


hearing


loss.


It consists


of written


responses


items


from


siX


different


categories:


Understanding


SDeech


with


Visual


Cues,


which


evaluates


ability


understand


connected


speech


when


Intensity


speaker


, which


face


describes


vis


person


s ability


detect


everyday


sounds


and


their


relative


loudness


Respons e


to Auditory


Failure,


which


addresses


how


the


person


manages


communication


breakdowns;


Environmental


Sounds


, which


addresses


issues


recogni


zing


familiar


sounds


auditorily


only


Understanding


Speech


with


Visual


Cues,


which


evaluates


speech


understanding


without


visual


cues


Personal,


designed


to eli


cit


the


patient


feelings


about


their


hearing


loss.


Two


other


categories


Occupation


and


General


are


evaluated


separately


The


former


is evaluated


in an employment


setting


three


areas:


Understanding c


Speech


with


Visual


Cme,


Response


to Auditory


Failure,


and


Personal


The


latter


is made


up of "general


communication"


items


that


did


not


into


any


the


other


categories,











question


based


on the


type


amplification


worn,


, for


that


particular


tuation.


For


each


question


there


are


possible


responses


that


are


assigned


a value


in the


following


manner:


- Never


- Almos

- Occas


Never


ionally


About


Half


The


Time


- Frequ


ently


- Practically


Always


the


person


responds


with


"Does


not


apply"


, the


item


scored.


mean


score


obtained


each


category


with


exception


General


and


Occupation


categories


which


are


interpreted


separately


In fact,


authors


state


that


"all


items


can


treated


singly


in a rehabilitative


program.


" (Owens


Raggio,


1988,


Owens


and


Raggio


(1988)


also


make


following


recommendations.


Regarding
profile,
warranted


each


results


the
the


use


because


scale
with


of percentage
of the small


Preferably,


a client,


the


mean


scores
number


discussing
numerical


not
items


the


scores


the


scales


corresponding
0-0.4 (never),


cas


esc


treated
riptive


0.5-1.4
ionally)


according
terms, as


(practically


.5-3


to the
follows
never),


half


the


tinsi


(fram1inH lf\


(nranti rall


Always


interpretation


individual


.5-2


(about


e;,d


d


.


-


1


.










56
mc1
UtYI ?~~7~i] 04
H





01


0 30
Cl) N.~Z

CT) ~C
V~

C C

(4-4

Ca 0

LU -

SC '4-4
t C3 -

z C'
C~OO




0
oP 0
(4-
*, $4
a0
r 4



rdU
a,~


-J

C-,










and


there


was


wide


variability


between


subjects.


Group


means


and


ranges


are


illustrated


Fig.


and


four


of the


areas


describe


group


s perception


their


communication


abilities


using


thecochlear


implant.


They


reported


that


they


frequently


understood


speech


with


visual


cues,


were


able


to detect


everyday


sounds


and


their


relative


loudness,


and


recognized


familiar


sounds


using


audition


alone.


addition,


they


were


able


to understand


speech


without


visual


cues


approximately


half


the


time.


Experimental


Procedures


The


experimental


test


procedures


consisted


reading


Grandfather


70 under


Passage


simultaneous


counting


delayed


backwards


auditory


from


feedback


(SAF/DAF).


These


tasks


were


performed


three


different


conditions


speech


proce


ssor


off,


speech


processor


and


conventional


amplification


the


unimplanted


ear.


To insure


uniformity


subjects


were


given


written


instructions


experimental


tasks


and


an opportunity


to clarify


any


questions


regarding


the


tasks.


Eauioment


Equipment


research


to conduct


consisted


test


protocol


following:


the


this


subject











58



(U






a.o 0
04


So 5.
0,
C



C C?




1C
C a H


CO~n 0C


LU eL
\w 1w
arEc




Li. c0




0 ~ 'a
aO C

r m,
F-' >0 On4I



no

*a 0

V.) ~ C. 0>

*( 1 40t
21 ;zc O
OC.- '
n5a










input


boot,


Unitron


Direct


Audio


Input


Kit,


AIWA


cassette


tape


recorder


with


one-half


inch


microphone.


The


functioning


the


cochlear


implant


was


checked


using


the


Nucleus


22-Channel


Cochlear


Implant


System.


This


system


is composed


an IBM


compatible


microcomputer,


dual


This


processor


system


interface


used,


(DPI),


initially,


and


customized


to create


a "map"


software.


, or


prescription,


the


individual


subject.


The


"map"


created


attaching


speech


processor


to the


programming


each


electrode


separately.


The


parameters


are


the


patients'


threshold


(the


softest


level


sound


they


reported


hearing)


and


maximum


comfort


level,


the


loudest,


comfortable


level


of sound.


Each


subj ect


s implant


was


checked


prior


their


participating


the


study.


This


was


accomplished


attaching


the


speech


processor


and


sweeping


the


electrodes,


allowing


comparison


and


confirmation


the


speech


processor


"map"


and


the


last


prescribed


"map.


According


the


manufacturer' s


product


information


sheet,


the


Phonic


Mirror


miniDAF


has


a delay


control


setting


of approximately


25 milliseconds


(ms)


at position


number


to a maximum


effect


delay


varying


of 220


auditory


ms at position


feedback


number


duration


The


was


"map"


.e.










possibility


ms delay


produced


the


miniDAF


unit


dial


selector


control)


influencing


subjects'


responses,


subjects


were


tested


the


SAF


condition


without

miniDAF.


their

This


speech


processor


necessitated


being


using


connected

separate


to the

microphones.


The


recording


microphone


was


connected


AIWA


cassette


tape


recorder


throughout


test


conditions.


additional


crophone


(Lapel


Microphone


AT 164),


provided


with


miniDAF,


was


added


during


DAF


test


procedures.


was


recognized


that


the


necess


using


microphones--one


recording


and


one


routing


speaker'

it could


addition,


output


there


through

overcome


was


the

with


DAF--was


an impedance


a limitation;


available


mismatch


however,


equipment.


between


cochlear


implant


speech


processor


and


miniDAF


unit.


overcome


Ear.


this,


It should


a custom

also be


patch


noted


cord

that


was

their


provided

e was no


Phonic


frequency


shaping


of the


signal


taking


place


as that


signal


was


routed


through


the


DAF;


therefore,


the


only


change


occurring


was


the


preset


delay


Mendoza,


personal


communication,


1990).


To calibrate


miniDAF


unit,


a signal


was


generated


using


Coulbourn


instrument


modules


This


signal


had


duration


of 20 milliseconds


(ms)


with


an instantaneous










electrical


output


was


into


a Tektronix


Type


oscilloscope.


The


delay


time


miniDAF


was


adjusted


visually


observing


output


displayed


oscilloscope.


Once


a 200


ms signal


rate


was


obtained


delay


control


knob


on the


miniDAF


was


secured


fixed


position.


end


data


collection,


delay


time


signal


was


confirmed


using


equipment


and


method


described


above.


Tes


ting


with


conventional


amplification


was


accomplished


using


a Unitron


UE PPL


behind


-the-ear


hearing


and


direct


audio


input.


The


use


the


boot


enabled


experimenter


to connect


hearing


aid


miniDAF.


The


boot


was


to exclude


the


hearing


aid


microphone


thereby


preventing


amplification


any


environmental


sounds.


result


this


arrangement


was


that


only


the


subject'


speech


was


transmitted


through


hearing


aid


and


miniDAF


unit.


The


subjects


wore


a stock,


regular


style,


earmold


during


testing


exception


this


was


one


subject


who


still


wears


a hearing


unimplanted


ear.


He used


own


regular


style


earmold.


An electroacoustical


analysis


the


hearing


aid


(ANSI,


1976)


the


was


study


conducted


to confirm


beginning


performance


and


conclusion


based


the


manufacturer'


specification


data.


Initially,


coupling










Seamans,


personal


communication,


1990).


This


was


achieved


using


the


attentuator


provided


with


the


direct


audio


input


kit.


The


attenuator


output


was


measured


electoacoustically,


and


maximum


attentuation


recorded


was


58 dB SPL.


hearing


aid


volume


control


was


to midlevel


(volume


setting


was


coupled


to the


attenuator.


The


attentuator


output


was


again


measured


output


control


knob


was


rotated,


the


knob


was


secured


fixed


position


when


attenuation


provided


was


18 dB


attenuation


. Seamans,


personal


communication,


1990).


Conditions


Three


experimental


conditions


were


evaluated:


cochlear


implant


off,


cochlear


implant


and


conventional


amplification


unimplanted


ear.


Two


experimental


treatments


were


administered


each


experimental


condition:


simultaneous


auditory


feedback


(SAF) ,


and


delayed


auditory


feedback


(DAF).


These


two


treatments


were


alternated


the


following


manner:


SAF


with


processor


off/on,


DAF


with


processor


off/on,


SAF


with


conventional


amplification.


amplification


SAF


always


and


preceded


DAF


with


DAF


conventional


each


condition


and


was


used


as baseline


data.










"off"),


the


"on"


condition


was


designated


an odd


number


"off"


condition


was


designated


an even


number.


Using


random


numbers


subject.


table,


that


a number


number


was


ended


selected


an odd


first


number,


the


condition


was


selected


as the


first


condition


and


"off"


condition


was


number


two.


number


selected


was


even


number


"off"


condition


was


selected


as the


first


condition,


was


second


subsequent


condition


subjects,


speech


conditions


processor


were


counterbalanced


based


on the


first


subject


(Hegde,


1987).


Written


instructions


reading


and


counting


tasks


were


given


to each


subject.


They


were


asked


to read


the


Grandfather


Passaae


silently


order


to familiarize


themselves


with


the


material.


Any


questions


were


answered


and


they


then


read


passage


aloud


SAF


condition.


Following


reading


they


were


given


the


written


instructions


counting


task.


They


were


initially


asked


to count


themselves


silently


and


then


count


aloud.


The


purpose


the


silent


counting


was


to allow


them


practice


and


so startled


request


that


any


difficulties


might


be due


surprise


the


request


and


to the


test


condition.


The


use


of backwards


counting


obtain


uniform


speech


sample


material


was


selected


based


"on"


I, on"










difficulty


with


this


type


task


than


younger


people.


Interpretation


counting


results


this


study


need


to be


made


with


these


limitations


mind.


Pfeiffer


(1975)


included


backward


counting


his,


Short


Potable


Mental


Status


Questionnaire


LSPMSO)


test


cognitive


functioning


older


adults,


since


this


skill


might


related


to cognitive


decline


the


elderly.


During


testing,


the


selected


volume


on the


miniDAF


was


based


on the


subject


s reported


comfort


level.


The


implant

miniDAF


speech


processor


unit


to-microphone


was


previous


distance


connected

v describe


inches


was


directly

d manner.


maintained


to the

A mouth-


using


head

164)


held


microphone


provided


with


set-up


miniDAF


the

unit.


lapel

This


microphone


allowed


subj ect


s speech


productions


to be passed


through


miniDAF


resulting


their


hearing


with


a 200


ms delay.


Following


completion


test


protocol


with


the


cochlear


implant


the


conditions


were


repeated


with


the


subject


wearing


the


Unitron


UE 12-PPL


behind-the-ear


hearing


aid


their


unimplanted


ears.


The


hearing


aid


internal


controls


were


set


to provide


widest


response,


and


the


volume


setting


was


selected


based


on the


subject


s reported


comfort


level.


To determine


test-retest


reliability


the










All


the


cassette


subjects


tape


recorder


esponses

using a


were


recorded


one-half


inch


on an AIWA

clip


microphone.


A mouth-to-microphone


distance,


the


recording


microphone,


.5 inches


was


maintained


during


testing.


Analysis


Data


Transcription


Consensus


transcription


(Shriberg


, Kwiatkowski,


Hoffmann,


1988),


using


the


International


Phonetic


Alphabet


(IPA)


was


performed


a speech-language


pathologist


and


experimenter


productions.


fourth


on all


A sound-by-sound


sentences


subject


analysis


Grandfather


s experimental


the


Passaae


speech


second


dresses


himself


an old


back


frock


coat


usually


several


buttons


missing


A long


beard


clings


to his


chin


giving


those


who


observe


him


a pronounced


feeling


the


utmost


respect.)


and


the


following


additional


words


from


the


passage:


cracked,


ilp)fl,


the,


short,


more,


mod


ern


was


performed


on the


subject


s speech


productions


in the


SAF


and


DAF


conditions.


This


sample


was


selected


based


on the


frequency


occurrence


the


phonemes


included


conversational


English

analysis


(Mines,

was pe


Hanson,


formedd


Shoup,


the


1978) .


Programs


The


phonological


to Examine


Phonetic


e


- -










input


phonetically


transcribed


speech


samples


and


analyze


them


type


and


frequency


of speech


sound


error.


subj ect


s utterances


during


counting


were


also


transcribed


analyzed


same


manner.


Following


transcription


the


samples,


data


were


entered


into


the


PEPPER


program


analysis.


The


program


scanned


consonant


and


vowel


productions


errors


based


on a standard


adult


model.


model


had


been


entered


from


a transcript


an adult,


female,


General


American


speaker


who


read


the


Grandfather


Passage


and


counted


backwards


from


Possible


errors


detected


included


omissions.


substitutions,


distortions


that


differed


significantly


from


standards


typical


production


suggested


Shriberg


(1986).


Intertranscriber


reliability


Swas


determined


the


samples.


These


were


selected


ass


signing


each


taped


test


condition


a number


between


and


and


then


drawing


them


out


of a box.


These


samples


were


independently


transcribed


another


speech-language


pathologist.


Two


commonly


used


techniques


calculating


interobserver


reliability


have


been


discussed


McReynolds


and


Kearns


(1983).


"total


method"


based


percentage


a study.


agreement


total


"Point-to-point"


number


reliability


observations


tallies


observer











may


agree


on the


total


number


responses


obtained,


agreement


lacking.


regarding


The


the


weakness


occurrence


the


target


"point-to-point"


behavior


method


"relates


the


fact


that


the


agreement


level


obtained


direct


behavior"


reflection


(McReynolds


rate


& Kearns,


of production


1983,


of the


150-151)


target


The


result


that


instances


extremely


high


or low


rates


of observed


behaviors


, there


a "high


probability


that


agreement


(McReynolds

pitfalls me


independent


will


be obtained


Kearn


ntioned


samples


s, p.

above


was


based


151) .

a 2X2


performed


on chance


an effort


chi-square


alone"


to avoid


analysis


to determine


reliability


between


the


transcribers


(Huck,


Cormier,


Bounds,


1974).


The


obtained


1738


.41,


df = 1,


was


significant


beyond


the


.001


level


confidence.


Statistical


Analysis


The


small


sample


= 8)


this


study


prohibited


use


parametric


statistics


therefore,


a Friedman


two-way


analysis


variance


(ANOVA)


was


performed


In addition,


effect


size


(ES)


was


calculated


duration,


consonant


errors,


and


vowel


errors


reading


and


counting


as well


the


cochlear


implant


and


hearing


aid


conditions.


Null


1~ ~rnn~hocn aim race 4-a nn't. i nf a narirn ~rrha n nn


rhnt-


r~CC


h vnnt h a C!a a


fih~


nn~ i nn


nk a n nm a n an


EIYn










convenient


use


the


phrase


'effect


size'


mean


'the


degree


which


phenomenon


is present


the


population.


'the


degree


to which


the


null


hypothesis


false'"'


. 9-10)


Regardless


the


type


of phenomenon


being

effect


studied,


size


"the

zero"


null

and


hypothesis


...the


always


larger


means


this


that


value,


the

the


greater


degree


to which


the


phenomenon


under


study


manifested


(Cohen,


1977


, p.


10) .


This


relationship


also


carries


over


to sample


size


where


...the


larger


posited,


other


things


significance


criterion,


desired


power)

detect


being

it" (


equal,


Cohen,


the

1977


smaller


, p.


the


sample


Effect


size


size


necessary


can


described


relative


terms


of "small"


, "medium,


and


large"


To describe


these


terms


further


, numerical


values


have


been


defined:


a "small"


effect


size


, (b)


"medium"


effect


size


"large


size


0.8.


summary,


the


res


earch


experiment


was


a factorial


design


with


independent


variables:


SAF,


DAF,


conventional


amplification,


speech


processor


, and


speech


processor


on.


The


dependent


variables


were:


reading


rate,


counting


rate,


and


occurrence


speech


the


errors.


subject


The


s speech


experimental


processor


design


two


can


conditions


described


(off,










and


the


repeated


measures


taken


on each


subject,


data


were


subjected


a Friedman


two-way


analysis


variance


(Marascuilo


& McSweeney


, 1977


Huck


et al


1974


and


to calculations


test-retest


of effect


reliability


the


(Cohen,


experimental


1977)


Finally


conditions


was


evaluated


using


Pearson


Product-Moment


statistic














CHAPTER ]
RESULTS


The


purpose


this


study


was


investigate


effect


of delayed


auditory


feedback


(DAF)


on the


speech


production


post-lingual


cochlear


implant


users.


In addition,


subjects


were


also


tested


wearing


conventional


amplification


their


unimplanted


ear.


The


specific


research


questions


formulated


this


study


were:


there


a difference


between


Simultaneous


Auditory


Feedback


(SAF)


and


Delayed


Auditory


Feedback


(DAF)


conditions


the


duration


reading


and


counting


cochlear


implant


users?


there


a difference


between


the


SAF


and


DAF


conditions


the


total


number


consonant


and


vowel


errors


made


cochlear


implant


users


during


reading


and


counting


tasks?


there


a difference


between


the


SAF


and


conditions


duration


reading


and


counting


cochlear


implant


users


when


wearing


a hearing


aid


alone?


there


a difference


between


the


SAF


and










vowel


errors


cochlear


implant


users


when


wearing


a hearing


aid


alone


and


performing


reading


and


counting


tasks?


Effect


on Reading


and


Counting


Duration


Means


and


Rances


Reading


and


counting


duration


means


and


ranges


seconds)


as a


function


amplification


type


and


feedback


condition


are


reported


Tabl


and


illustrated


Figure


and


Figure


Examination


reading


duration


means


and


ranges


revealed


no differences


between


SAF


and


DAF


the


absence


amplification


(SAF


= 50.2


, DAF


= 49.0


However,


there


were


duration


differences


between


the


SAF


DAF


means


when


subjects


were


tested


with


the


cochlear


implant


(SAF


= 50.5


, DAF


= 64.0


and


the


hearing


aid


(SAF


= 49.1


, DAF


= 63


. Wide


ranges


reading


duration


were


also


noted


when


subjects


wore


either


cochlear


implant


or the


hearing


aid


Counting


duration


means


remained


similar


under


SAF/DAF


the


absence


of amplification


SAF


= 32


, DAF


with


the


cochlear


implant


(SAF


33.0


, DAF


36.8)


and


with


hearing


aid


(SAF


= 32


, DAF


35.1)


However,


counting


duration


varied


among


subjects











Table


Duration


means


conditions
hearing aid
auditory fe
Grandfather


and


ranges


amplification,


)


under


edback


ssaqe


second


cochlear


simultaneous


SAF/DAF)


and


when


counting


and


) in three
implant,
delayed


reading
backwards


SAF


Amplification


Time


Ranges
Seconds


Time/


Ranges
Seconds


Reading


None


49.0


40 57


- 57


- 58


64.0


102

107


63.0


Counting


None


- 49


33.0


**HA


- 48


- 49


20 50


23 59


35.1


18 49


*CI
**HA


= Cochlear
= Hearing


Implant
Aid


**HA









73




.QI


Ir ~
""41-4
0.0

o Li
u-c


O


CC
o> 2
Z 00
Th 00


"et
.4 P

O me N.
o- W~QiC
00CC r
0) kHU

I IB'
Cd V
CO4


O~)B


kOC
00Q


0 0"

oo 0 0
C'J
1~ ( 0Q)ZC










74



S01

r4Wr
00a




LL o U



C:



___~ C 0
o O


MC k
4i~r%


-JC
HO C
-~ 'coo


WCO

I r-
401
1C 43
QIW 0 M r4
4rW






SC--

o 0 0 0 0 0
o 0 (0 N
r: 46










ANOVA


A Friedman


performed


two-way


answer


analysis


each


variance


research


(ANOVA)


questions.


was


This


statistical


a group


method


data,


assigns r

yielding


anks


to each


a mean


rank


the


score


mean

for e


scores


ach


condition.


rank


The


scores,


greater


greater


differences


difference


between


between


mean


test


measures.


Duration


There


were


no significant


differences


either


duration


duration


of reading--X2(5,

of counting--X2(5,


= 8)


= 8)


.23,


= 9.96,


.14--or


<.07--in


the


the


SAF


and


conditions,


regardless


absence


presence


of amplification.


The


mean


rank


scores


reading


counting


duration


are


summarized


Table


and


Figure


and


Table


and


Figure


, respectively.


Examination


reading


mean


rank


scores


Table


revealed


that


the


absence


amplification


subj ects


scores


were


larger


.19)


SAF


condition


than


DAF


condition


.63)


indicating


that


their


reading


duration


was


longer


under


SAF.


Opposite


results


were


obtained


with


the


cochlear


implant


hearing


aid.


Mean


rank


scores


when


the


cochlear


implant


was


worn


were


(SAF)










Table


Mean


rank


reading
implant,
delayed


scores


and


conditions


hearing
auditory


effect


size


values


amplification,


aid)


under


feedback


simultaneo


(SAF/


three


cochlear
us and


DAF)


Reading


Duration


Amplification


Devi


None


HA**


SAF


2.88


DAF


5.00


0.96


0.99


(B) Consonant Errors


Amplification Device

SAF 5.87 1.69 3.94

DAF 4.44 4.13 3.00

ES 0.22 0.76 0.44


(C) Vowel Errors


Amplification Device

SAF 3.75 2.44 3.25

DAF 5.50 3.81 2.94

ES 0.24 0.65 0.41


ES***










































SAF


DAF










Table


Mean


rank


counting
implant,
delayed


scores


and


conditions


hearing
feedback


aid)
(SAF


effect


size


values


amplification,


under


simultaneou


three


cochlear
s and


/DAF)


Counting


Duration


Amplification


Devi


None


HA**


SAF


0.28


(B) Consonant Errors


Amplification Device

SAF 3.31 3.44 3.50

DAF 3.19 4.19 3.38

ES 0.19 0.52 0.17


(C) Vowel Errors


Amplification Device

SAF 4.06 2.88 3.38

DAF 3.06 4.31 3.31

ES 0.48 1.02 0.08


ES***

















5.13


SAF


DAF










further


evaluate


these


data,


calculations


effect


size


(ES)


were


performed


(Cohen,


1977)


was


stated


Chapter


, effect


size


not


intended


to imply


a cause


and


effect


relationship


but


rather


degree


to which


a relationship


between


two


measures


may


exist


(Cohen,


1977)


A large


effect


size


would


suggest


that


differences


did


exist


between


conditions,


e.g


SAF


and


Effect


size


values


reading


duration


are


summarized


Table


A small


value


was


seen


without


amplification,


very


large


values


were


seen


both


the


cochlear


implant


.96)


and


hearing


aid


.99)


conditions


Counting


The


counting


duration


mean


rank


scores


are


summarized


Table


5 and


illustrated


Figure


These


results


indicate


that


subjects


took


longer


to perform


counting


task


under


DAF


.81)


than


under


SAF


.88)


The


same


pattern


was


observed


when


cochlear


implant


was


worn,


(DAF)


and


(SAF)


Thi


pattern


continued


when


the


subjects


wore


the


hearing


aid


under


DAF


.06)


under


SAF


duration


.69)


tasks


can


results


seen


yielded


the


Tabi


same


counting


pattern


values


absence


of amplification,


i.e.


a small


value


.30),


that


was


noted


reading


data.


Unlike


* r


rrl -I~


W


--










DAT


Effect


on Number


of_ CosnntRll oe -nr
-. wrr U.. U W- p -..*


Means


and


RanQes


Means


and


ranges


consonant


and


vowel


errors


during


reading


and


counting


are


presented


Table


6 and


Table


and


illustrated


omissions,


Figures


substitutions,


through


and


deletions


All


nonstandard


of consonants


and


vowels


were


counted


as errors.


Suggestions


from


the


PEPPER


manual


(1986)


were


used


to determine


variations


productions


were


standard,


casual


speech


or errors.


Readinca.


Examination


of Table


6 revealed


small


differences


in the


number


of reading


consonant


errors


the


absence


amplification


(SAF


= 6.8),


and


with


the


hearing


aid


(SAF


- 6.3,


.8) .


There


were


large


differences


range


scores


, however,


indicating


wide


variability


among


the


subj ects


under


SAF


DAF


Vowel


reading


errors


followed


the


same


pattern,


i.e.,


small


differences


between


the


SAF/DAF


condition.


The


means


were


(SAF)


and


(DAF)


absence


amplifica-


tion,


(SAF)


and


(DAF)


with


the


cochlear


implant,


(SAF)


and


(DAF)


with


hearing


aid.


The


ranges


were


smaller


vowel


errors,


with


the


exception


amplification


condition


(SAF


- 17,


DAF


- 25).


of Consnn~n+


;rnrl


VnwP 1


kl~mr~










Table


Mean


and


ranges


three conditions
implant, hearing
delayed auditory


Grandfather


for c
(no
aid)


:onsonant


and


amplification,


under


feedback


(S


vowel


errors


cochlear


simultaneous
AF/DAF) when


Passage.


and
reading


Consonant


Errors


SAF


Amplification


Ranges
Errors


Ranges
Errors


None


- 18

- 15

- 9


**HA


Vowel


Errors


SAF


DAF


Amplification


Ranges
Errors


Ranges
Errors


None


- 17


- 25


**HA


*CI
**HA


= Cochlear
= Hearing


Implant
Aid










Table


Means


and


ranges


three conditions
implant, hearing
delayed auditory
backwards.


for
(no
aid)


consonant


and


amplification,


under


feedback


(S


vowel


errors


cochlear


simultaneous
AF/DAF) when


and
counting


Consonant


Errors


Amplification


Ranges
Errors


Ranges
Errors


None


14.1


- 34


- 22


- 22


**HA


- 21


16.2


- 24

- 24


14.7


Vowel


Errors


SAF


DAF


Amplification


Ranges
Errors


Ranges
Errors


None


- 17


**HA


- 14


*CI
**HA


= Cochlear
= Hearing


Implant
Aid









84







Cc


LCQ

CON
'C

C U (/




And





o 'a

Sal


OC

Os~r

(C O





COWr
0'0
SOCr


LL
-
00Q


CO


Va






















VC


ON~
*~c

.aCC


Cc4


ra,
2rQ
d C 0I
rdC1 J)
Sc~l
0.0
0-*4'-
O I V
1.4Z
0000 c


-CkU),
0~)000

OWVf

00


tacoI
000
rs'-CO




Cr40
0.te
CClr


0CCE
Sc










86



ft.

C1

I Via

Cr4
LL Q00

S0)
0'



C
Cud
C:

o CH ~
Z0
Z~ ov 4)
SO'4
Ct MC Wki



040)
0200


d04)
CD>.
-- 000,



0CC
00r
""'2



(I)lll C4J





CO V
OWOC


4) O









87







I~C *rII





C r



Co v

Et)
8i l

IFV
CWOO
m 1.40
r (0,-Ea
O 1.10>1
Z r WoO0

>CC


cno



WBUL

z m 0 V

CSk 0H











12.8,


DAF


= 16.2


with


hearing


aid


(SAF


= 13


DAF


= 14.7)


However


the


ranges


consonant


counting


errors


were


very


large


in the


SAF


and


condition.


Means


vowel


counting


errors


also


yielded


small


differences


between


SAF


without


amplification


(SAF


, DAF


with


cochlear


implant


(SAF


= 1.1


= 6.1),


and


with


hearing


aid


(SAF


, DAF


The


pattern


of a wide


range


scores


among


subjects


seen


previous


experimental


conditions


continued


vowel


counting


errors.


ANOVA


Reading


. The


results


the


Friedman


two-way


ANOVA


were


= 8)


11.64,


and


= 8)


= 7.75,


, for


reading


consonant


vowel


errors,


respectively


These


findings


revealed


that


the


introduction


of DAF


number


did


result


consonant


a significant


or vowel


errors


difference


reading.


Mean


rank


scores


reading


consonant


errors


are


summarized


Table


4 and


Figure


They


indicate


greater


number


errors


under


SAF


.87)


versus


.44)


the


absence


amplification.


pattern


was


repeated


when


the


subjects


wore


hearing


aid


under


SAF


.94)


under


DAF


I -


.001 .


However. th


pattern


was


reversed


when














5,87


SAF


DAF










more


consonant


errors


were


produced


under


.13)


than


under


SAF


69).


Examination


of effect


size


reading


consonant


errors


revealed


small


ES values


.22)


the


absence


amplifica-


tion


and


with


the


hearing


aid


A moderate


ES value


was


noted


with


cochlear


implant.


Mean


rank


Table


scores

Figure


of vowel


reading


DAF


errors


condition


are summarized

yielded larger


mean


rank


scores


reading


vowel


errors


absence


amplification


than


SAF


condition


.75)


This


was


the


case


when


subj ects


wore


the


cochlear


implant


reading


under


vowel


DAF


errors


.81)


were


versus


smaller


under


with


SAF


the


.44)


However,


hearing


under


.94)


than


SAF


.25)


Small


effect


size


values


reading


.24)


vowel


and


errors


with


were


hearing


obtained


aid


without


.41).


amplification


A moderate


value,


0.65,


was


obtained


with


the


cochlear


implant.


Countina.


Statistical


analysis


counting


errors


revealed


, E.


<.92


consonant


errors


and


= 8)


, p.


vowel


errors.


This


lack


significant


differences


between


the


SAF


and


conditions


the


counting


task


followed


the


same


pattern


shown


the


reading


task.


X2~5,



















5.5


SAF


DAF


---


























4.19


3 31 3 .4 4 3 .5
3sq 4

H re
II
b+=+ u

ii+i$4


3,19


3.38


SAF


DAF




Full Text

PAGE 1

7+( ())(&7 2) '$) 21 63((&+ 352'8&7,21 2) 3267/,1*8$/ &2&+/($5 ,03/$17 86(56 32//< 6+,33 *5(< $ ',66(57$7,21 35(6(17(' 72 7+( *5$'8$7( 6&+22/ 2) 7+( 81,9(56,7< 2) )/25,'$ ,1 3$57,$/ )8/),//0(17 2) 7+( 5(48,5(0(176 )25 7+( '(*5(( 2) '2&725 2) 3+,/2623+< 81,9(56,7< 2) )/25,'$ 81,9(56,7< 2) )/25,'$ /,%5$5,(6

PAGE 2

'(',&$7,21 7KLV GLVVHUWDWLRQ LV ORYLQJO\ GHGLFDWHG WR (GZDUG &UDZIRUG 6KLSS 3ROO\ 0RRUH 6KLSS f (GZDUG 5RGJHUV *UH\ 9LUJLQLD )DUUHOO *UH\

PAGE 3

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f f f

PAGE 4

, ZRXOG OLNH WR H[SUHVV P\ JUDWLWXGH WR 0UV 5XE\ 0RRUH RI t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

PAGE 5

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f f f f 9OO Y

PAGE 6

9 ',6&866,21 5HDGLQJ DQG &RXQWLQJ 'XUDWLRQ &RQVRQDQW (UURUV 9RZHO (UURUV &RFKOHDU ,PSODQW 9HUVXV +HDULQJ $LG P 7\SHV RI 6SHHFK (UURUV 6XPPDU\ &RQFOXVLRQV $33(1',; ,V 727$/ 180%(5 2) &21621$17 (55256 '85,1* 5($',1* $33(1',; 727$/ 180%(5 2) 92:(/ (55256 '85,1* 5($',1* $33(1',; 727$/ 180%(5 2) &21621$17 (55256 '85,1* &2817,1* $33(1',; 727$/ 180%(5 2) 92:(/ (55256 '85,1* &2817,1* $33(1',; '85$7,21 ,1 6(&21'6 '85,1* 5($',1* $33(1',; '85$7,21 ,1 6(&21'6 '85,1* &2817,1* 5()(5(1&(6 %,2*5$3+,&$/ 6.(7&+ YL

PAGE 7

$EVWUDFW RI 'LVVHUWDWLRQ 3UHVHQWHG WR WKH *UDGXDWH 6FKRRO RI WKH 8QLYHUVLW\ RI )ORULGD LQ 3DUWLDO )XOILOOPHQW RI WKH 5HTXLUHPHQWV IRU WKH 'HJUHH RI 'RFWRU RI 3KLORVRSK\ 7+( ())(&7 2) '$) 21 63((&+ 352'8&7,21 2) 3267/,1*8$/ &2&+/($5 ,03/$17 86(56 %\ 3ROO\ 6KLSS *UH\ 0D\ &KDLUPDQ 3DWULFLD % .ULFRV 3K' &R&KDLUPDQ $OLFH 7 '\VRQ 3K' 0DMRU 'HSDUWPHQW &RPPXQLFDWLRQ 3URFHVVHV DQG 'LVRUGHUV 7KH SXUSRVH RI WKLV VWXG\ ZDV WR LQYHVWLJDWH WKH HIIHFW RI GHOD\HG DXGLWRU\ IHHGEDFN '$)f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f DQG GHOD\HG DXGLWRU\ IHHGEDFN '$)f LQ WKUHH FRQGLWLRQV Df FRFKOHDU LPSODQW Ef KHDULQJ DLG DQG Ff QR DPSOLILFDWLRQ ,Q HDFK FRQGLWLRQ WKH\ UHDG D SDVVDJH DQG FRXQWHG EDFNZDUGV IURP WR 7KH VXEMHFWVn VSHHFK VDPSOHV ZHUH WUDQVFULEHG XVLQJ WKH ,QWHUQDWLRQDO 3KRQHWLF f f 9OO

PAGE 8

$OSKDEHW DQG ZHUH DQDO\]HG IRU WRWDO QXPEHU RI FRQVRQDQW DQG YRZHO HUURUV XVLQJ WKH 3URJUDP WR ([DPLQH 3KRQHWLF DQG 3KRQRORJLF (YDOXDWLRQ 5HFRUGV 3(33(5f 'LIIHUHQFHV EHWZHHQ WKH 6$) DQG '$) FRQGLWLRQV LQ WKH GXUDWLRQ RI UHDGLQJ DQG RI FRXQWLQJ ZHUH DOVR PHDVXUHG LQ VHFRQGV 7KH GDWD ZHUH VXEMHFWHG WR D )ULHGPDQ 7ZR:D\ $QDO\VLV RI 9DULDQFH $129$f 7KHUH ZHUH QR VWDWLVWLFDOO\ VLJQLILFDQW GLIIHUHQFHV LQ SHUIRUPDQFH UHJDUGOHVV RI WKH WDVN RU FRQGLWLRQ VXJJHVWLQJ WKH DEVHQFH RI D '$) HIIHFW +RZHYHU DQ DSSDUHQW '$) HIIHFW ZDV GHWHFWHG GXULQJ WUDQVFULSWLRQ RI WKH UHFRUGHG GDWD 7KLV ZDV LQYHVWLJDWHG IXUWKHU E\ FDOFXODWLQJ HIIHFW VL]H YDOXHV EHWZHHQ 6$)'$) DQG WKH GLIIHUHQW H[SHULPHQWDO WDVNV /DUJH HIIHFW VL]H YDOXHV XQGHU '$) ZHUH REWDLQHG IRU Df UHDGLQJ GXUDWLRQ ZLWK WKH FRFKOHDU LPSODQW f DQG WKH KHDULQJ DLG f DQG Ef FRXQWLQJ YRZHO HUURUV f ZLWK WKH FRFKOHDU LPSODQW 7KHVH ODUJH HIIHFW VL]HV LQGLFDWHG WKDW VXEMHFWV WRRN ORQJHU WR UHDG WKH SDVVDJH ZKHQ ZHDULQJ HLWKHU GHYLFH DQG PRUH YRZHO FRXQWLQJ HUURUV ZHUH PDGH ZKHQ ZHDULQJ WKH FRFKOHDU LPSODQW (IIHFW VL]H YDOXH FRPSDULVRQV EHWZHHQ WKH WZR GHYLFHV LQGLFDWHG D ODUJH '$) HIIHFW VL]H f IRU YRZHO UHDGLQJ HUURUV ZLWK WKH FRFKOHDU LPSODQW ,Q VXPPDU\ D SRVVLEOH '$) HIIHFW ZDV HYLGHQW LQ VRPH FRQGLWLRQV EXW ZDV QRW VXSSRUWHG E\ VWDWLVWLFDO WHVWLQJ f f f 9OOO

PAGE 9

&+$37(5 ,1752'8&7,21 7KH PRVW SUHYDOHQW FKURQLF GLVDELOLW\ LQ WKH SRSXODWLRQ RI WKH 8QLWHG 6WDWHV LV KHDULQJ LPSDLUPHQW 3XQFK f ,W LV HVWLPDWHG WKDW PLOOLRQ $PHULFDQV KDYH VRPH GHJUHH RI KHDULQJ ORVV DQG DSSUR[LPDWHO\ b RI WKHVH SHRSOH DUH SURIRXQGO\ KHDULQJ LPSDLUHG LH GHDI 1DWLRQDO &HQWHU IRU +HDOWK 6WDWLVWLFV f ,Q WKLV JURXS RI SURIRXQGO\ KHDULQJLPSDLUHG SHRSOH DUH VRPH ZKR QR ORQJHU UHFHLYH RU KDYH QHYHU UHFHLYHG EHQHILW IURP FRQYHQWLRQDO DPSOLILFDn WLRQ 7KH UHDVRQV IRU WKLV YDU\ EXW LQFOXGH LQFUHDVHV LQ V\PSWRPV RI WLQQLWXV RU YHUWLJR DQG DQ LQWROHUDQFH WR YLEURWDFWLOH VHQVDWLRQV WKDW FDQ DFFRPSDQ\ WKH XVH RI SRZHUIXO DPSOLILFDWLRQ (LVHQEHUJ %HUOLQHU +RXVH DQG (GJHUWRQ f DV ZHOO DV WKH ULVN RI FDXVLQJ DGGLWLRQDO GDPDJH WR WKH HDU +XPHV t %HVV f /DVWO\ WKHUH LV LQ VRPH FDVHV RI SURIRXQG KHDULQJ ORVV WKH LQDELOLW\ WR RYHUFRPH WKH KHDULQJ ORVV YLD DPSOLILFDWLRQ 7KH FULWLFDO LQIOXHQFH RI KHDULQJ DQG WKH HIIHFWV RI YDU\LQJ GHJUHHV RI KHDULQJ ORVV RQ WKH DFTXLVLWLRQ RI VSHHFK DQG ODQJXDJH LV ZHOO HVWDEOLVKHG &DOYHUW t 6LOYHUPDQ *ROG +XGJLQV t 1XPEHUV /HYLWW 0F*DUU t *HIIQHU 0RQVHQ 6PLWK f 5HVHDUFK LQWR WKH VSHHFK

PAGE 10

SURGXFWLRQ RI WKH SRVWOLQJXDOO\ KHDULQJ LPSDLUHG LH LQGLYLGXDOV ZKR GHYHORSHG KHDULQJ ORVV DIWHU DFTXLULQJ VSHHFK DQG ODQJXDJH KDV EHHQ GHVFULEHG DV WR JHQHUDOO\ FRQVLVW>LQJ@ RI DQHFGRWDO UHSRUWV 6H\IULHG +XWFKLQVRQ t 6PLWK f +RZHYHU D FRPSDULVRQ VWXG\ RI DUWLFXODWRU\ SDWWHUQV LQ D QRUPDOKHDULQJ DQG D SRVWOLQJXDOO\ GHDIHQHG DGXOW E\ =LPPHUPDQ DQG 5HWWDOLDWD f VXJJHVWHG WKH LPSRUWDQFH RI DXGLWRU\ LQIRUPDWLRQ LQ PRQLWRULQJ DQG PDLQWDLQLQJ VSHHFK FRRUGLQDWLYH VWUXFWXUHV %RRWKUR\G f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f 7KHLU SDWLHQW D \HDUROG GHDI PDQ GHVFULEHG VRXQG VHQVDWLRQV KH H[SHULHQFHG DV VRXQGLQJ OLNH FULFNHWV RU D URXOHWWH ZKHHO ,Q DGGLWLRQ KH UHSRUWHG DQ DZDUHQHVV RI EDFNJURXQG VRXQGV DQG KLV LQFUHDVHG DZDUHQHVV RI VSHHFK UK\WKP HQDEOHG KLP LQ WLPH WR LPSURYH KLV VSHHFKUHDGLQJ VNLOOV 7KLV HQFRXUDJLQJ QHZV DORQJ ZLWK DGYDQFHV LQ WKH VXUJLFDO

PAGE 11

WHFKQLTXHV DQG WKH GHVLJQ RI VWLPXODWLQJ GHYLFHV UHVXOWHG LQ LQWHUHVW E\ RWKHUV LQ WKH PHGLFDO FRPPXQLW\ %\ 'U :LOOLDP ) +RXVH DQG -DFN 8UEDQ DQ HOHFWULFDO HQJLQHHU KDG GHYHORSHG WKH ILUVW FRFKOHDU LPSODQW LQ WKH 8QLWHG 6WDWHV +RXVH f &RFKOHDU LPSODQWV DUH VXUJLFDOO\ LPSODQWHG GHYLFHV WKDW DOORZ WKH SURIRXQGO\ KHDULQJ LPSDLUHG WR H[SHULHQFH VRXQG 7KH ILUVW LPSODQWV XVHG D VLQJOH HOHFWURGH FKDQQHOf EXW ZLWK EHWWHU WHFKQRORJ\ DQG FRQWLQXLQJ UHVHDUFK VRPH RI WRGD\nV GHYLFHV PDNH XVH RI PXOWLSOH HOHFWURGHV PXOWLFKDQQHOf $OO RI WKH LPSODQWV HQDEOH WKH XVHU WR H[SHULHQFH VRXQG VHQVDWLRQ E\ VWLPXODWLQJ WKH DXGLWRU\ QHUYH 7RGD\ WKHUH DUH PRUH WKDQ SHRSOH ZKR KDYH UHFHLYHG HLWKHU D VLQJOH RU PXOWLFKDQQHO FRFKOHDU LPSODQW *ROGVWHLQ t )ULHGHOZDOG f ,Q JHQHUDO LW FDQ EH VDLG WKDW WKH HIIHFWLYHQHVV RI WKH FRFKOHDU LPSODQW LV YDULDEOH 6RPH RI WKH YDULDELOLW\ FDQ EH DWWULEXWHG WR WKH GLIIHUHQFHV DPRQJ WKH SHRSOH UHFHLYLQJ DQ LPSODQW LH GLIIHUHQFHV LQ DXGLRORJLFDO PHGLFDO SV\FKRORJLFDO VRFLDO DQG FRPPXQLFDWLRQ KLVWRULHV DV ZHOO DV WKH W\SH RI GHYLFH LPSODQWHG 3HUIRUPDQFH ZLWK DQ LPSODQW FDQ UDQJH IURP WKH LQGLYLGXDO ZKR FDQ RQO\ GLVWLQJXLVK EHWZHHQ HQYLURQPHQWDO VRXQGV IRU H[DPSOH FDU WUDIILF YHUVXV D GRRUEHOOf WR D SHUVRQ ZKR LV DEOH WR HQJDJH LQ QRUPDO FRQYHUVDWLRQDO GLVFRXUVH ZLWKRXW YLVXDO FXHV DERXW SHUFHQWf /DQVLQJ f 7KH PRVW FRPPRQO\ UHSRUWHG EHQHILW WR WKH FRFKOHDU LPSODQW UHFLSLHQW

PAGE 12

UHJDUGOHVV RI W\SH RI GHYLFH LV DQ LPSURYHPHQW LQ VSHHFKUHDGLQJ DELOLW\ /DQVLQJ f 7KH VSHHFK SHUFHSWLRQ RI FRFKOHDU LPSODQW UHFLSLHQWV ZKR XVH VLQJOH RU PXOWLFKDQQHO GHYLFHV KDV EHHQ ZHOO GRFXPHQWHG %LOJHU (GGLQJWRQ (LVHQEHUJ HW DO +ROPHV .HPNHU t 0HUZLQ f 7KHUH KDV EHHQ OHVV UHVHDUFK RQ WKH VSHHFK SURGXFWLRQ RI WKHVH SDWLHQWV 7KH GHYLFH GRHV VHHP WR RIIHU EHQHILW LQ WKLV DUHD DV HYLGHQFHG E\ WKH UHSRUWHG LPSURYHPHQW LQ ORXGQHVV FRQWURO DQG YRFDO TXDOLW\ WKDW KDV EHHQ DWWULEXWHG WR WKH XVHUnV DELOLW\ WR VHOIPRQLWRU KLVKHU VSHHFK SURGXFWLRQV &KRXDUG HW DO (LVHQEHUJ HW DO (QJHOPDQQ :DWHUIDOO t +RXJK )RXUFLQ HW DO f 7KHVH VWXGLHV ZKLOH FRPPHQWLQJ RQ WKH VSHHFK RI WKHLU VXEMHFWV ZHUH QRW GHVLJQHG WR VSHFLILFDOO\ LQYHVWLJDWH VSHHFK SURGXFWLRQ 6RPH SRVWOLQJXDO DQG PDQ\ SUHOLQJXDO KHDULQJLPSDLUHG KDYH VLJQLILFDQW SUREOHPV FRPPXQLFDWLQJ GXH WR WKHLU SRRU VSHHFK &RZLH DQG 'RXJODV&RZLH f UHSRUWHG WKDW RQH RI WKHLU VXEMHFWV FDUULHG D OHWWHU H[SODLQLQJ WR SHRSOH WKDW KLV VOXUUHG VSHHFK ZDV GXH WR KLV GHDIQHVV DQG QRW WR KLV EHLQJ GUXQN 7R EHWWHU DGGUHVV WKH LVVXH RI VSHHFK SURGXFWLRQ RI FRFKOHDU LPSODQW XVHUV PRUH UHVHDUFK LV QHHGHG 7KH IRFXV RI WKLV UHVHDUFK SURMHFW ZDV WR H[DPLQH WKH HIIHFW RI GHOD\HG DXGLWRU\ IHHGEDFN '$)f RQ WKH VSHHFK SURGXFWLRQ RI SRVWOLQJXDOO\ GHDIHQHG FRFKOHDU LPSODQW XVHUV LQ DQ HIIRUW

PAGE 13

WR REWDLQ REMHFWLYH HYLGHQFH RI WKHLU XVH RI WKHLU QHZ DXGLWRU\ LQIRUPDWLRQ WR PRQLWRU WKHLU VSHHFK SURGXFWLRQ 'HOD\HG DXGLWRU\ IHHGEDFN '$)f UHIHUV WR DQ H[SHULPHQWDOO\ LQGXFHG WLPH GHOD\ LQ D VSHDNHUnV KHDULQJ RI KLVKHU YRLFH 1RUPDOO\ WKH LQGLYLGXDO KHDUV KLVKHU VSRNHQ XWWHUDQFHV ZLWKLQ DSSUR[LPDWHO\ RQH PLOOLVHFRQG
PAGE 14

$ GHPRQVWUDWHG '$) HIIHFW ZRXOG VHHP WR VXJJHVW WKDW WKH FRFKOHDU LPSODQW XVHU ZDV PDNLQJ XVH RI DXGLWRU\ FXHV DV GLG WKH KHDULQJLPSDLUHG FKLOGUHQ GLVFXVVHG LQ WKH 0D[RQ HW DO f VWXG\ 6SHFLILFDOO\ IRU D SRSXODWLRQ RI HLJKW SRVWOLQJXDOO\ GHDIHQHG FRFKOHDU LPSODQW VXEMHFWV WKH UHVHDUFK TXHVWLRQV WR EH IRUPXODWHG ZHUH f f ,V WKHUH D GLIIHUHQFH EHWZHHQ WKH 6$) DQG '$) FRQGLWLRQV LQ WKH GXUDWLRQ RI UHDGLQJ DQG FRXQWLQJ E\ FRFKOHDU LPSODQW XVHUV" ,V WKHUH D GLIIHUHQFH EHWZHHQ WKH 6$) DQG '$) f FRQGLWLRQV LQ WKH WRWDO QXPEHU RI FRQVRQDQW DQG YRZHO HUURUV PDGH E\ FRFKOHDU LPSODQW XVHUV GXULQJ UHDGLQJ DQG FRXQWLQJ WDVNV" ,V WKHUH D GLIIHUHQFH EHWZHHQ WKH 6$) DQG '$) FRQGLWLRQV LQ WKH GXUDWLRQ RI UHDGLQJ DQG FRXQWLQJ E\ FRFKOHDU LPSODQW XVHUV ZKHQ ZHDULQJ D KHDULQJ DLG DORQH" f ,V WKHUH D GLIIHUHQFH EHWZHHQ WKH 6$) DQG '$) FRQGLWLRQV LQ WKH WRWDO QXPEHU RI FRQVRQDQW DQG YRZHO HUURUV E\ FRFKOHDU LPSODQW XVHUV ZKHQ ZHDULQJ D KHDULQJ DLG DORQH DQG SHUIRUPLQJ UHDGLQJ DQG FRXQWLQJ WDVNV"

PAGE 15

&+$37(5 ,, 5(9,(: 2) 7+( /,7(5$785( 7KHUH DUH PDQ\ GLIIHUHQW IRUPV RI FRPPXQLFDWLRQ KRZHYHU WKH RQH ZKLFK LV XQLTXH WR KXPDQV LV VSHHFK 6SHHFK FRPPXQLFDWLRQ FDQ EH GHVFULEHG XVLQJ D IHHGEDFN PRGHO LQ ZKLFK WKHUH LV D VHQGHU WKH VSHDNHUf D PHVVDJH DQG D UHFHLYHU WKH OLVWHQHUf 7KH IHHGEDFN LV D FRPELQDWLRQ RI DXGLWRU\ YLVXDO WDFWLOH DQG NLQHVWKHWLF H[SHULHQFHV :KHQ WKHUH LV D GLVUXSWLRQ LQ WKH DXGLWRU\ IHHGEDFN SRUWLRQ DV LQ WKH FDVH RI SURIRXQG KHDULQJ ORVV PHDQLQJIXO VSHHFK SHUFHSWLRQ LV WHUPLQDWHG DQG VSHHFK SURGXFWLRQ PD\ EH DIIHFWHG =LPPHUPDQQ t 5HWWDOLDWD &RZLH 'RXJODV &RZLH t .HUU 3ODQW f ,Q RUGHU WR UHHVWDEOLVK WKH DXGLWRU\ IHHGEDFN PHFKDQLVP GHYLFHV KDYH EHHQ GHYHORSHG ZKLFK GLUHFWO\ VWLPXODWH WKH DXGLWRU\ QHUYH DUH FDOOHG FRFKOHDU LPSODQWV 7KH DGGLWLRQDO DXGLWRU\ LQIRUPDWLRQ SURYLGHG E\ WKH LPSODQW HQDEOHV VRPH XVHUV WR XQGHUVWDQG VSHHFK DXGLWRULO\ %HUOLQHU 7RQRNDZD '\H t +RXVH +ROPHV .HPNHU t 0HUZLQ 7\H0XUUD\ t 7\OHU f DQG DOVR HQKDQFHV VSHHFKUHDGLQJ DELOLW\ %DOODQW\QH f ,Q DGGLWLRQ UHVHDUFKHUV KDYH UHSRUWHG LPSURYHPHQWV LQ WKH VSHHFK SURGXFWLRQ DQG YRLFH FKDUDFWHULVWLFV RI VRPH LPSODQW XVHUV .LUN DQG (GJHUWRQ

PAGE 16

/HGHU 6SLW]HU .LUFKQHU )OHYDULV3KLOOLSV 0LOQHU 5LOFKDUGVRQ f 7KH SXUSRVH RI WKLV VWXG\ LV WR H[DPLQH WKH UHn HVWDEOLVKHG IHHGEDFN V\VWHP LQ FRFKOHDU LPSODQW XVHUV E\ LQYHVWLJDWLQJ WKH HIIHFWV RI GHOD\HG DXGLWRU\ IHHGEDFN RQ WKH VSHHFK SURGXFWLRQ RI FRFKOHDU LPSODQW XVHUV ZLWK SRVW OLQJXDO GHDIQHVV 7KLV FKDSWHU ZLOO UHYLHZ QRUPDO KHDULQJ VSHHFK SURGXFWLRQ DQG SHUFHSWLRQ WKH HIIHFWV RI GHOD\HG DXGLWRU\ IHHGEDFN RQ QRUPDOKHDULQJ DQG KHDULQJLPSDLUHG LQGLYLGXDOV XVLQJ FRQYHQWLRQDO DPSOLILFDWLRQf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f

PAGE 17

1RUPDO 6SHHFK 3URGXFWLRQ DQG 3HUFHSWLRQ 9HUEDO FRPPXQLFDWLRQ LV D FRPSOH[ VHULHV RI DFWV GHSHQGHQW XSRQ WKH VSHDNHU SURGXFLQJ D VWULQJ RI FRQWUDVWLQJ VRXQGV ZKLFK ZKHQ KHDUG E\ WKH OLVWHQHU FDQ EH GHFRGHG DQG WKH PHVVDJH XQGHUVWRRG 7KLV SURFHVV XVXDOO\ WDNHV SODFH ZLWK HDVH GXH WR WKH SHUVRQnV NQRZOHGJH RI WKH ODQJXDJH V\VWHP DQG WKH DQDWRP\ DQG SK\VLRORJ\ RI WKH VSHHFK DQG KHDULQJ VWUXFWXUHV %HFDXVH RI WKHVH XQLTXH VWUXFWXUHV KXPDQ EHLQJV KDYH WKH FDSDFLW\ WR OHDUQ WR SURGXFH DQG UHFRJQL]H PDQ\ GLIIHUHQW VRXQGV ,Q WKH (QJOLVK ODQJXDJH WKHUH DUH DERXW IRUW\ SKRQHPHV LH FODVVHV RI VRXQGV WKDW RQH VRXQG IURP DQRWKHU /LQJ t /LQJ 0DFND\ f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f 7KH IXQGDPHQWDO IUHTXHQF\ IRU DGXOW PDOHV W\SLFDOO\ RFFXUV EHWZHHQ DQG +] IRU DGXOW IHPDOHV EHWZHHQ DQG +] DQG IRU \RXQJ FKLOGUHQ EHWZHHQ DQG +] (JXFKL t +LUVK f

PAGE 18

9RZHOV 9RZHO SURGXFWLRQ UHVXOWV IURP D FRPELQDWLRQ RI H[KDOHG DLU SDVVLQJ WKURXJK WKH YLEUDWLQJ YRFDO IROGV RYHU WKH WRQJXH DQG RXW RI WKH PRXWK &KDQJHV LQ WKH GHJUHH WR ZKLFK WKH MDZ LV RSHQ WKH SRVLWLRQ RI WKH OLSV DQG WKH VKDSH DQG SRVLWLRQ RI WKH WRQJXH LQIOXHQFH WKH DFRXVWLFDO SURSHUWLHV RI WKH SURGXFHG VRXQGV \LHOGLQJ D GLVWLQFW VHW RI IRXUWHHQ VRXQGV ZKLFK FRPSULVH (QJOLVK YRZHOV 'HZ t -HQVHQ f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f (DFK YRZHO KDV LWV RZQ FKDUDFWHULVWLF IRUPDQW SDWWHUQ DQG HDFK LQGLYLGXDO KLVKHU RZQ FKDUDFWHULVWLF VL]H DQG VKDSHG YRFDO WUDFW 7KH UHVXOW LV WKDW WZR GLIIHUHQW VSHDNHUV ZLOO SURQRXQFH WKH VDPH YRZHO VRPHZKDW GLIIHUHQWO\ 'HVSLWH WKHVH GLIIHUHQFHV i LW LV WKH IRUPDQW SDWWHUQV ZKLFK WHQG WR UHPDLQ FRQVWDQW DOORZLQJ XV WR UHFRJQL]H WKH SDUWLFXODU YRZHO ZKHWKHU WKH VSHDNHU LV DQ DGXOW PDOH RU IHPDOHf RU D FKLOG 0DF.D\

PAGE 19

f ,Q RUGHU IRU D SHUVRQ WR SHUFHLYH WKRVH FULWLFDO ILUVW WZR IRUPDQWV WKH\ QHHG WR EH DEOH WR KHDU LQ WKH UDQJH RI WR +] IRU WKH IRUPDQW ),f DQG EHWZHHQ WR +] IRU WKH VHFRQG IRUPDQW )f 6NLQQHU f 'LSKWKRQJV DUH SKRQHPHV PDGH XS RI WZR YRZHO VRXQGV DQG RFFXU DV SKRQHPHV ZKLFK JOLGH IURP RQH YRZHO SRVLWLRQ WR DQRWKHU 7KH IUHTXHQF\ RI D GLSKWKRQJ LV GHWHUPLQHG E\ WKH ILUVW IRUPDQW YDOXHV RI HDFK YRZHO EHLQJ DGGHG WRJHWKHU DQG WKH VHFRQG IRUPDQW YDOXHV EHLQJ DGGHG WRJHWKHU JLYLQJ DQ DSSUR[LPDWLRQ RI WKH IUHTXHQF\ UDQJH IRU WKH SDUWLFXODU GLSKWKRQJ /LQJ t /LQJ f &RQVRQDQWV &RQVRQDQWV DUH WKH VHFRQG ODUJH FODVV RI VRXQGV DQG DUH SURGXFHG E\ FKDQJLQJ WKH DLUIORZ RXW RI WKH PRXWK 7KH DQQHU LQ ZKLFK WKH DLU IORZ LV LQWHUUXSWHG \LHOGV WKUHH GLVWLQFW W\SHV RI FRQVRQDQWV f SORVLYHV ZKLFK UHVXOW ZKHQ WKH DLUIORZ LV FRPSOHWHO\ EORFNHG VXFK DV LQ WKH VRXQGV SWN f IULFDWLYHV UHVXOWLQJ IURP WKH DLUIORZ EHLQJ UHVWULFWHG DV LQ WKH VRXQGV IYHVK RU f QDVDOV ZKHUH WKH DLU IORZ LV GLUHFWHG WKURXJK WKH QRVH DV LQ WKH VRXQGV PQT ,Q DGGLWLRQ WR WKH DERYH W\SHV DQRWKHU GLVWLQFWLYH IHDWXUH RI FRQVRQDQW SURGXFWLRQ LQYROYHV YRLFLQJ 9RLFLQJ UHIHUV WR WKH WLPLQJ RI WKH YRFDO IROG YLEUDWLRQ LQ UHODWLRQ WR WKH UHOHDVLQJ RI WKH VRXQG WKDW LV EHLQJ VSRNHQ ,W L

PAGE 20

WKLV IHDWXUH ZKLFK DOORZV IRU WKH GLVWLQFWLRQ EHWZHHQ WKH YRLFHG SORVLYH E DQG LWV YRLFHOHVV FRJQDWH S 'XULQJ WKH SURGXFWLRQ RI E YRFDO IROG YLEUDWLRQ DQG WKH UHOHDVH RI WKH E RFFXU DW DSSUR[LPDWHO\ WKH VDPH WLPH ZLWKLQ WR PVHFf" LQ FRQWUDVW WKHUH LV D WLPH ODJ EHWZHHQ WKH YLEUDWLRQ RI WKH YRFDO IROGV DQG WKH UHOHDVH RI WKH S JUHDWHU WKDQ WR PVHFf PDNLQJ LW D YRLFHOHVV VSHHFK VRXQG 'HZ t -HQVHQ f /LVNHU DQG $EUDPVRQ f FRLQHG WKH WHUP YRLFH RQVHW WLPH 927f WR GHVFULEH WKH UHODWLYH WLPLQJ RI WKH FRQVRQDQW UHOHDVH DQG WKH RQVHW RI f f YRLFLQJ 9RLFLQJ SHUFHSWLRQ LV GHSHQGHQW RQ ORZ IUHTXHQF\ LQIRUPDWLRQ XVXDOO\ LQ WKH UDQJH RI WR +] IRU DGXOW VSHDNHUV DQG DW KLJKHU IUHTXHQFLHV IRU FKLOGUHQ 6WHYHQV f 7KH UDQJH RI KHDULQJ QHFHVVDU\ IRU FRQVRQDQW SHUFHSWLRQ YDULHV ZLWK WKH GLIIHUHQW PDQQHU RI SURGXFWLRQ DQG DOVR ZLWKLQ D SDUWLFXODU FODVV RI FRQVRQDQWV 3ORVLYHV FDQ EH HLWKHU YRLFHG E G Jf RU YRLFHOHVV S W Nf 7KH SORVLYHV ES DUH UHODWLYHO\ ORZ IUHTXHQF\ VRXQGV KDYLQJ WKH PDMRULW\ RI WKHLU FRQFHQWUDWHG HQHUJ\ EHWZHHQ DQG +] 7KH JUHDWHVW HQHUJ\ IRU GW LV IRXQG EHWZHHQ DQG +] DQG WKH HQHUJ\ FRQFHQWUDWLRQ IRU N YDULHV IURP WR +] GHSHQGLQJ RQ WKH IUHTXHQF\ RI WKH VHFRQG IRUPDQW RI WKH YRZHO DGMDFHQW WR N 6NLQQHU f )ULFDWLYHV DUH DOVR LQ YRLFHGYRLFHOHVV SDLUV DQG WKHLU DUHDV RI FRQFHQWUDWHG HQHUJ\ YDU\ DOVR 7KH HQHUJ\

PAGE 21

UDQJH IRU WKH V] SDLU LV DSSUR[LPDWHO\ WR +] DQG WKH SDLU DURXQG WR +] $QRWKHU DFRXVWLF FXH WR GLIIHUHQWLDWLQJ IULFDWLYH VRXQGV LV LQWHQVLW\ DQG GXUDWLRQ 7KH YIKH DUH OHVV LQWHQVH DQG RI VKRUWHU GXUDWLRQ WKDQ WKH ; SKRQHPHV 6NLQQHU f 1DVDO VRXQGV DUH SURGXFHG E\ WKH VRXQG EHLQJ HPLWWHG IURP WKH QRVH UDWKHU WKDQ WKH PRXWK 7KH\ DUH DOO YRLFHG DQG DUH FKDUDFWHUL]HG E\ D ORZ IUHTXHQF\ QDVDO PXUPXU LQ WKH UDQJH RI WR +] ,Q DGGLWLRQ WR SORVLYHV IULFDWLYHV DQG QDVDOV WKHUH DUH RWKHU FRQVRQDQW VRXQGV ZKLFK UHVHPEOH YRZHOV DQG DUH FDOOHG JOLGHV ZMf DQG VHPLYRZHOV U f FKDUDFWHUL]HG E\ FKDQJLQJ IRUPDQWV DQG VHPLYRZHOV E\ D IRUPDQW FRQILJXUDWLRQ VLPLODU WR YRZHOV EXW PRUH UHVWULFWHG LQ LWV WRWDO IUHTXHQF\ UHJLRQ 6NLQQHU f )LQDOO\ WKH FRQVRQDQW HTXLYDOHQW WR WKH GLSKWKRQJ LV WKH DIIULFDWH 7KH DIIULFDWH LV D FRPELQDWLRQ RI D YRLFHG SORVLYH FRPELQHG ZLWK D YRLFHG IULFDWLYH GAf RU WKH YRLFHOHVV SORVLYH FRPELQHG ZLWK WKH YRLFHOHVV IULFDWLYH W-f (IIHFW RI +HDULQJ /RVV RQ 6SHHFK 3URGXFWLRQ DQG 3HUFHSWLRQ 7R EH DEOH WR XQGHUVWDQG VSHHFK HVSHFLDOO\ XQGHU OHVV WKDQ RSWLPDO FRQGLWLRQV ZH DUH GHSHQGHQW XSRQ RXU LQQHU

PAGE 22

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t 6LOYHUPDQ *ROG +XGJLQV t 1XPEHUV /HYLWW t 6WURPEHUJ /HYLWW 0F*DUU t *HIIQHU 0RQVHQ f 7KHUH LV OHVV UHVHDUFK DYDLODEOH RQ WKH HIIHFWV RI DFTXLUHG KHDULQJ ORVV LQ WKH SRVWOLQJXDO GHDI SRSXODWLRQ DQG DFFRUGLQJ WR HW DO f PXFK WKDW LV UHSRUWHG LV JHQHUDOO\ DQHFGRWDO 7KHUH LV JUHDW YDULDELOLW\ LQ WKH VSHHFK SURGXFWLRQ RI WKH SRVWOLQJXDOO\ GHDI SRSXODWLRQ 7KLV YDULDELOLW\ KDV EHHQ UHIOHFWHG LQ WKH OLWHUDWXUH LQFOXGLQJ WKH YLHZ WKDW DGYHQWLWLRXV GHDIQHVV GRHV QRW UHVXOW LQ GLVRUGHUHG VSHHFK *RHKO t .DXIPDQ f =LPPHUPDQQ DQG 5HWWDOLDWD f FRPSDUHG WKH DUWLFXODWRU\ SDWWHUQV RI DQ DGYHQWLWLRXVO\ GHDIHQHG DGXOWnV VSHHFK WR WKDW RI D QRUPDO KHDULQJ VSHDNHU 7KH GHDI VXEMHFW ZDV D \HDUROG PDOH ZKR LQLWLDOO\ H[KLELWHG D KLJK IUHTXHQF\ VHQVRULQHXUDO KHDULQJ ORVV ZKLFK SURJUHVVHG

PAGE 23

WR LQFOXGH WKH ORZ IUHTXHQFLHV 7KH KHDULQJ ORVV UHSRUWHGO\ RFFXUUHG EHWZHHQ HDUO\ DQG ODWH DGROHVFHQFH DQG ZDV RI XQNQRZQ RULJLQ 7KH VXEMHFWn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f $W WKH WLPH RI WKLV VWXG\ DQ LQIRUPDO DVVHVVPHQW RI WKH VXEMHFWnV VSHHFK E\ WZR WUDLQHG OLVWHQHUV MXGJHG DOO RI WKH VXEMHFWnV XWWHUDQFHV WR EH SKRQHPLFDOO\ 7KH VSHHFK WDVN IRU WKH VXEMHFW ZDV WR VD\ >ELE@ >EDE@ >VL@ >EDU@ >UDE@ LQ WKH FDUULHU SKUDVH 7KDWnV D S f $UWLFXODWRU\ SDWWHUQV RI WKH VXEMHFW ZHUH UHFRUGHG XVLQJ KLJK VSHHG FLQHIOXRURJUDSK\ DQG FRPSDUHG ZLWK WKH QRUPDO KHDULQJ FRQWURO 7KH VSHHFK SURGXFWLRQV RI WKH GHDI VXEMHFW UHYHDOHG V\VWHPDWLF WLPLQJ GLIIHUHQFHV LQ WKH b FORVLQJ SRUWLRQ RI HDFK XWWHUDQFH GHYLDWLRQV LQ

PAGE 24

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f IRU VSHHFK S f &RZLH HW DO f VWXGLHG WZHOYH SRVWOLQJXDOO\ GHDIHQHG DGXOWV LQ 1RUWKHUQ ,UHODQG $OO RI WKHLU VXEMHFWV ZHUH FODVVLILHG DV KDYLQJ SURIRXQG ELODWHUDO VHQVRULQHXUDO KHDULQJ ORVV ZLWK WKH H[FHSWLRQ RI RQH VXEMHFW ZKR KDG VRPH KHDULQJ LQ RQH HDU EXW ZDV ORVLQJ LW 7KH SXUSRVHV RI WKHLU VWXG\ ZHUH WR f DQDO\]H DUWLFXODWLRQ HUURUV f SURYLGH XVHIXO PHDVXUHPHQWV RI WKH VXEMHFWnV LQWHOOLJLELOLW\ DQG f LGHQWLI\ SUREOHPV RWKHU WKDQ LQWHOOLJLELOLW\ WKDW WKH VXEMHFWV UHSRUWHG 7DSH UHFRUGLQJV RI WKH KHDULQJLPSDLUHG VXEMHFWV UHDGLQJ ILYH VKRUW SDVVDJHV DQG FRQYHUVLQJ VLQJO\ RU LQ JURXSV ZLWK D QRUPDO LQWHUYLHZHU ZHUH PDGH 5HFRUGLQJV ZHUH DOVR PDGH RI RQH QRUPDO KHDULQJ VXEMHFW XQGHU WKH DERYH FRQGLWLRQV 7HQ QRUPDO KHDULQJ VXEMHFWV ZHUH DVVLJQHG WR

PAGE 25

OLVWHQ WR HDFK KHDULQJLPSDLUHG VXEMHFWnV UHFRUGLQJ 6SHHFK LQWHOOLJLELOLW\ ZDV PHDVXUHG XVLQJ D VKDGRZ WHFKQLJXH 7KLV WHFKQLTXH LQYROYHG WKH QRUPDO KHDULQJ VXEMHFWV OLVWHQLQJ WR WKH WDSHG UHFRUGLQJV DQG DWWHPSWLQJ WR UHSHDW YHUEDWLP ZKDW ZDV VDLG DV LW ZDV EHLQJ VDLG 7KH SHUFHQWDJH RI FRUUHFWO\ UHSHDWHG ZRUGV ZDV WKH PHDVXUH RI LQWHOOLJLELOLW\ 7KH DXWKRUV OLVWHG WKH IROORZLQJ FDYHDW UHJDUGLQJ WKH OHYHO RI LQIRUPDWLRQ SURYLGHG E\ WKLV WHFKQLTXH f LW LV D UHODWLYH PHDVXUH RI LQWHOOLJLELOLW\ f WKH UHVXOWV GR QRW LGHQWLI\ FXWRII SRLQWV EHWZHHQ VXEMHFWV ZLWK LQWHOOLJLELOLW\ SUREOHPV DQG WKRVH ZLWK QRUPDO KHDULQJ DQG f PHDVXUHPHQWV XVLQJ WKLV WHFKQLTXH DUH QRW GLUHFWO\ FRPSDUDEOH WR VWXGLHV RI WKH SUHOLQJXDOO\ GHDI 'HVSLWH WKH DERYH OLPLWDWLRQV WKH UHVXOWV REWDLQHG GLG VXJJHVW WZR SRLQWV f PRVW RI WKH VXEMHFWV KDG PHDVXUDEOH ORVVHV LQ LQWHOOLJLELOLW\ DQG f WKHUH ZDV YDULDELOLW\ DPRQJ WKH VXEMHFWV DOO VXEMHFWV SHUWDLQHG WR f VW\OH DQG FRQWHQW RI WKH UHDGLQJ SDVVDJH LQ ZKLFK WKH VLPSOHU WKH VW\OH DQG PRUH IDPLOLDU WKH WRSLF WKH KLJKHU WKH LQWHOOLJLELOLW\ VFRUHV DQG f DJH DW RQVHW RI GHDIQHVV VHHPHG WR KDYH WKH JUHDWHVW HIIHFW RQ LQWHOOLJLELOLW\ ZLWK WKH WZR ZRUVH VSHDNHUV EHFRPLQJ GHDI EHIRUH \HDUV RI DJH DQG WKH WZR EHVW VSHDNHUV EHFRPLQJ GHDI DIWHU +RZHYHU WKH DXWKRUV FDXWLRQ WKDW D ODUJHU VDPSOH LV QHHGHG EHIRUH JHQHUDOL]DWLRQV DERXW WKLV ILQGLQJ

PAGE 26

FDQ EH PDGH 7KH DXWKRUV DOVR QRWHG WKDW WKHLU GDWD GLG QRW VXJJHVW WKDW IDFWRUV VXFK DV VRFLDO EDFNJURXQG LQWHOOLJHQFH RU PRWLYDWLRQ ZHUH UHOHYDQW 2WKHU SUREOHPV UHODWHG WR VSHHFK GHWHULRUDWLRQ ZHUH H[SORUHG LQ WKLV VWXG\ E\ HYDOXDWLQJ QRUPDOKHDULQJ OLVWHQHUn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f 7KH DXWKRUV FRQFOXGHG WKDW WKHVH ILQGLQJV VXJJHVW WKDW SRVWOLQJXDOO\ GHDI LQGLYLGXDOV H[SHULHQFH VRPH GHJUHH RI VSHHFK GHWHULRUDWLRQ EXW WKHUH LV ZLGH YDULDELOLW\ LQ WKLV SRSXODWLRQ DQG DJH DW RQVHW RI GHDIQHVV DSSHDUHG WR EH D UHOHYDQW IDFWRU LQ WKH OHYHO RI GHWHULRUDWLRQ 7KH VLJQLILFDQW VSHHFK GHWHULRUDWLRQ LQ PDQ\ RI WKH VXEMHFWV LOOXVWUDWHG WKH QHHG IRU PRUH DWWHQWLRQ WR VSHHFK FRQVHUYDWLRQ LQ WKLV SRSXODWLRQ WR HQDEOH WKHP WR IXQFWLRQ LQ WKH KHDULQJ ZRUOG 3ODQW f UHSRUWHG FDVH VWXG\ ILQGLQJV RI D PDOH VXEMHFW GHDIHQHG E\ PHQLQJLWLV DW DJH \HDUV 7KH VXEMHFWnV VSHHFK SURGXFWLRQ ZDV HYDOXDWHG LQ WKH IROORZLQJ

PAGE 27

DUHDV f SKRQHWLF HUURUV LQ VSRQWDQHRXV DQG UHDG VSHHFK f LQWHOOLJLELOLW\ HUURUV XVLQJ PRQRV\OODELF ZRUGV DQG f UDWLQJV E\ QRUPDOKHDULQJ OLVWHQHUV RI WKH VXEMHFWn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nV H[DJJHUDWHG FDUH DQG SUHFLVLRQ ZKLOH UHDGLQJ OHDGLQJ WR D KLJKO\ DUWLILFLDO VDPSOH S f 7KH VXSUDVHJPHQWDO IHDWXUHV RI VSHHFK ZHUH IRXQG WR VKRZ GHYLDWLRQV IURP WKH QRUP DOVR 7KH GHYLDWLRQV QRWHG f LQDELOLW\ WR FRQWURO SLWFK f SURGXFWLRQ RI DOO V\OODEOHV ZLWK HTXDO VWUHVV DQG f VORZHU WKDQ QRUPDO UDWH RI VSHDNLQJ 5HFRUGLQJV RI WKH VXEMHFWnV SURGXFWLRQ RI IRXU OLVWV RI PRQRV\OODELF ZRUGV ZHUH SUHVHQWHG WR QRUPDO KHDULQJ

PAGE 28

OLVWHQHUV 7KH OLVWHQHUV JDYH ZULWWHQ UHVSRQVHV WR ZKDW WKH\ KHDUG DQG WKHVH UHVSRQVHV ZHUH UHFRUGHG RQ FRQIXVLRQ PDWULFHV IRU LQLWLDO FRQVRQDQWV YRZHOV DQG ILQDO FRQVRQDQWV ,QLWLDO FRQVRQDQW HUURUV UHSUHVHQWHG b RI WKH SUHVHQWDWLRQV DQG RI WKRVH HUURUV DIIULFDWHV ZHUH WKH PRVW FRPPRQO\ PLVXQGHUVWRRG bf $GGLWLRQDO DQDO\VLV RI WKH DIIULFDWHV UHYHDOHG WKDW WKH YRLFHOHVV DIIULFDWH -rf DFFRXQWHG IRU b RI WKH HUURUV ,Q DGGLWLRQ RI WKRVH HUURUV RYHU b LQYROYHG VXEVWLWXWLQJ WKH FRQVRQDQWDO EOHQG WU IRU WI 7KH YRLFHG DIIULFDWH GJf \LHOGHG DQ HUURU UDWH RI b RI WKH SUHVHQWDWLRQV DQG DOPRVW b RI WKRVH HUURUV LQYROYHG VXEVWLWXWLRQ RI WKH EOHQG GU IRU GA 7KH DXWKRU VXJJHVWHG WKDW UHODWLYHO\ ZHDN WDFWLOH FXHV IRU WKH UHOHDVH SKDVH RI WKH DIIULFDWHV QHFHVVLWDWHV DXGLWRU\ PRQLWRULQJ WR PDLQWDLQ FRUUHFW SURGXFWLRQ $QDO\VLV RI YRZHO DQG GLSKWKRQJ HUURUV LQGLFDWHG FRQIXVLRQ ZLWK DGMDFHQW YRZHOV VXJJHVWLQJ RYHUODSSLQJ RI IRUPDQW YDOXHV Sf 7KLV ZDV IXUWKHU VXSSRUWHG E\ WKH QXPEHU RI HUURUV EHWZHHQ YRZHOV ZLWK VLPLODU ), YDOXHV ZKLFK ZDV H[SODLQHG E\ WKH IDFW WKDW WKH )nV DUH PRUH GLVWRUWHG DQG WKH VXEMHFWnV NQRZOHGJH RU PHPRU\ RI WRQJXH SODFHPHQW KDG EHHQ DGYHUVHO\ DIIHFWHG E\ WKH KHDULQJ ORVV 7KLV YLHZ ZDV IXUWKHU VXSSRUWHG E\ HYLGHQFH WKDW PRUH GLSKWKRQJV ZHUH

PAGE 29

nfSHUFHLYHG DV VWHDG\ VWDWH UDWKHU WKDQ G\QDPLF PRYHPHQWV S f &RQYHUVHO\ WKH YRZHOV ZHUH FRUUHFWO\ SHUFHLYHG DV VWHDG\ VWDWH 7KH JUHDWHVW QXPEHU RI FRQVRQDQW HUURUV LQYROYHG SODFH RI DUWLFXODWLRQ 7KHVH ILQGLQJV DJUHH ZLWK WKRVH RI =LPPHUPDQQ DQG 5HWWDOLDWD f DQG IXUWKHU VXSSRUW WKH LPSRUWDQFH RI DXGLWLRQ LQ WKH SURGXFWLRQ RI FORVLQJ JHVWXUHV IRU VSHHFK :LWKRXW V\QFKURQRXV DQG FRUUHFW DUWLFXODWRU\ SDWWHUQV WKHUH PD\ EH D EOXUULQJ RI SODFH FXHV 3ODQW f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f WDNH H[FHSWLRQ WR WKLV YLHZ E\ FULWLFL]LQJ D VWXG\ E\ %LQQLH 'DQLORII DQG %XFNLQJKDP f DQG DUJXH WKDW WKRVH DXWKRUV GLG QRW WDNH LQWR FRQVLGHUDWLRQ WKH VXEMHFWnV DJH

PAGE 30

\HDUV PRQWKVf DW WKH WLPH KHDULQJ ZDV ORVW 7KH\ HPSKDVL]HG WKDW WKH RQVHW RI GHDIQHVV UHVXOWHG LQ DQ LQWHUUXSWLRQ LQ WKH PDWXUDWLRQ RI WKH FKLOGnV SKRQRORJLF 7KH\ VSHFXODWHG WKDW WKLV LQDELOLW\ WR FRQWLQXH WR OHDUQ VSHHFK DXGLWRULO\ IURP RWKHUV ZRXOG DFFRXQW IRU WKH VSHHFK GHWHULRUDWLRQ DQG ZRXOG EH DV LPSRUWDQW DV ORVV RI DXGLWRU\ IHHGEDFN 7KH\ TXHVWLRQHG VSHHFK WUDLQLQJ WHFKQLTXHV XVHG ZLWK WKH FKLOG WKHVH WHFKQLTXHV ZHUH QRW GHVFULEHGf DQG ILQDOO\ WKH SRVVLEOH FRQWLQXLQJ UHVLGXDO HIIHFWV IURP WKH HWLRORJ\ RI WKH KHDULQJ ORVV PHQLQJLWLVf 7KHVH DXWKRUV DOVR UDLVH TXHVWLRQV UHJDUGLQJ =LPPHUPDQQ DQG 5HWWDOLDWDnV f LQWHUSUHWDWLRQ RI WKHLU GDWD QRWHG WKDW WKHVH DXWKRUV SRLQWHG RXW WKH LQDELOLW\ WR JHQHUDOL]H WKHLU ILQGLQJV GXH WR WKH VDPSOH VL]H 1 7KH\ f DQG WKH FRQVLGHUDEOH YDULDELOLW\ LQ VSHHFK SURGXFWLRQ DFURVV VSHDNHUV UHJDUGOHVV RI WKHLU DELOLW\ WR KHDU RU QRW ,Q DGGLWLRQ WKH\ TXHVWLRQHG ZKHWKHU WKH GLIIHUHQFHV EHWZHHQ WKH KHDULQJ DQG GHDI VXEMHFWV ZHUH UHDO GLIIHUHQFHV EHFDXVH RI WKH OLPLWDWLRQV RI GHVFULELQJ WKH XWWHUDQFHV EHLQJ MXGJHG DV SKRQHPLFDOO\ DFFXUDWH S f E\ WKH WZR WUDLQHG OLVWHQHUV LH QR IRUPDO FOLQLFDO DVVHVVPHQW ZDV PDGH RI WKH VXEMHFWVn VSHHFK SULRU WR WKHLU H[SHULPHQW 'XH WR WKH ODFN RI HPSLULFDO GDWD DQG WKH JHQHUDO H[SHFWDWLRQV E\ FOLQLFLDQV WKDW VSHHFK GHWHULRUDWHV RYHU WLPH LQ GHDI SDWLHQWV *RHKO DQG .DXIPDQ XVHG VL[ $6+$

PAGE 31

VSHHFKODQJXDJH SDWKRORJLVWV DV MXGJHV WR GHWHUPLQH LI WKHUH ZHUH LGHQWLILDEOH FKDQJHV LQ WKH VSHHFK RI QRUPDO KHDULQJ DQG GHDI VXEMHFWV 7KH VSHFLILF TXHVWLRQV DGGUHVVHG LQ WKH VWXG\ ZHUH ZKHWKHU WKRVH H[SHUW ZRXOG EH DEOH WR f MXGJH DUWLFXODWLRQ DV ZLWKLQ QRUPDO OLPLWV DQG f LGHQWLI\ DQ\ RI WKH VSHDNHUV DV EHLQJ DGYHQWLWLRXVO\ GHDIHQHG S f 7KH VXEMHFWV ZHUH GLYLGHG LQWR WZR JURXSV GHDI DQG KHDULQJ DQG ZHUH PDWFKHG IRU VH[ DQG ZHUH VLPLODU LQ DJH WR \HDUV ROGf 7KH GHDI JURXS ZDV VHOHFWHG IURP D SRRO RI WZHOYH ZKR ZHUH DWWHQGLQJ D JURXS DW WKH WLPH RI WKH VWXG\ %DVHG RQ WKHLU DXGLRPHWULF UHVXOWV WKH\ ZHUH H[SHFWHG WR GHYHORS VSHHFK GHYLDWLRQV GXH WR WKHLU GHJUHH RI KHDULQJ ORVV &DOYHUW f 7KH FRQWURO JURXS EDVHG RQ DXGLRPHWULF HYDOXDWLRQ ZDV GHWHUPLQHG WR KDYH QRUPDO IRU DJH OHYHOf KHDULQJ (DFK VXEMHFW ZDV WDSHG UHDGLQJ WKH *UDQGIDWKHU 3DVVDJH 7KH SDVVDJHV ZHUH UDQGRPL]HG DQG WKH RUGHU RI SUHVHQWDWLRQ ZDV UHYHUVHG IRU HYHU\ RWKHU MXGJH 7KH VHFRQG TXHVWLRQ LH LGHQWLILFDWLRQ RI GHDI VSHDNHUVf ZDV DOZD\V SUHVHQWHG DIWHU WKH ILUVW LH LGHQWLILFDWLRQ RI QRUPDO DUWLFXODn WLRQf LQ RUGHU WR SUHYHQW OLVWHQHU ELDV ,W ZDV DOVR GRQH WR JLYH WKH OLVWHQHU XQOLPLWHG WULDOV LQ RUGHU WR PDNH D GHFLVLRQ DERXW WKH VXEMHFWVn UHVSRQVHV DQG DYRLG PHDVXULQJ WKH MXGJHVn DELOLW\ WR GR D WLPHG WDVN

PAGE 32

7KH UHVXOWV LQGLFDWHG WKDW DOO RI WKH VXEMHFWV ZHUH MXGJHG WR KDYH QRUPDO DUWLFXODWLRQ EXW WKDW GHDIHQHG VSHDNHUV FRXOG EH LGHQWLILHG DW EHWWHU WKDQ FKDQFH OHYHO ,Q DGGLWLRQ QHLWKHU WKH QXPEHU RI \HDUV VLQFH WKH RQVHW RI GHDIQHVV QRU WKH GHJUHH RI LPSDLUPHQW VHHPHG UHODWHG WR WKH OLVWHQHUnV ODEHOLQJ WKH VSHDNHU DV GHDI 7KH DXWKRUV UHSRUWHG WKDW D UHYLHZ RI WKH FRPPHQWV RI WKH MXGJHV GHVFULELQJ WKH VSHHFK RI WKRVH VXEMHFWV LGHQWLILHG DV GHDI LQFOXGHG GLIIHUHQFHV LQ UK\WKP UDWH YRLFH TXDOLW\ DQG VOLJKWO\ LQDFFXUDWH DUWLFXODWLRQ SDUWLFXODUO\ LQ UHJDUG WR VLELODQWV S f *RHKO DQG .DXIPDQ VXJJHVWHG WKDW WKHVH ILQGLQJV PD\ EH VXSSRUWHG E\ =LPPHUPDQQ DQG 5HWWDOLDWD f KRZHYHU WKH\ DOVR SRLQWHG RXW WKDW VRPH RI WKH MXGJHV LQ WKHLU VWXG\ PLVLGHQWLILHG VRPH QRUPDO VXEMHFWV 7KH\ DOVR SRLQW RXW WKH SRVVLEOH LQIOXHQFH RI WKH H[SHFWDWLRQV ZKLFK WKH MXGJHV EURXJKW WR WKHLU WDVN RQFH WKH\ NQHZ WKDW WKH VXEMHFWV ZHUH GHDI 7KHVH H[SHFWDWLRQV ZHUH GHVFULEHG DV D ZLOOLQJQHVV RQ WKH SDUW RI WKH MXGJHV WR WROHUDWH PLOG FKDQJHV LQ VSHHFK WKDW DUH DVVRFLDWHG ZLWK DQ HOGHUO\ SRSXODWLRQ UDWH YRLFH DUWLFXODWLRQf DQG VWLOO FRQFOXGH WKDW VSHHFK SURGXFWLRQ ZDV ZLWKLQ QRUPDO OLPLWV *RHKO DQG .DXIPDQ FRQFOXGHG WKDW FOLQLFDOO\ VLJQLILFDQW VSHHFK SURGXFWLRQ GHWHULRUDWLRQ DV D UHVXOW RI DGYHQWLWLRXV GHDIQHVV ZDV QRW VXSSRUWHG E\ WKHLU GDWD ,Q DGGLWLRQ WKH\ VWDWHG WKDW WKH YLHZ WKDW DXGLWRU\ IHHGEDFN LV HVVHQWLDO WR

PAGE 33

PDLQWDLQLQJ VSHHFK EDVHG RQ D VHUYRPHFKDQLVP WKHRU\ RI VSHHFK FRQWURO ZDV DOVR QRW VXSSRUWHG LQ WKHLU VWXG\ $FTXLUHG KHDULQJ ORVV SURGXFHV YDULDEOH HIIHFWV RQ WKH VSHHFK RI SRVWOLQJXDOO\ GHDIHQHG DGXOWV 7KH ORVV RI DXGLWRU\ PRQLWRULQJ FDSDELOLWLHV KDV EHHQ WKH DWWULEXWLQJ FDXVH RI VSHHFK GHWHULRUDWLRQ LQ VRPH RI WKLV SRSXODWLRQ &RZLH HW DO 3ODQW =LPPHUPDQQ t 5HWWDOLDWD f $ GLVVHQWLQJ YLHZ ZDV UHSRUWHG E\ *RHKO DQG .DXIPDQ f )LQDOO\ WKH QHHG IRU PRUH UHVHDUFK LQ WKLV DUHD LV DSSDUHQW GXH WR WKH ODFN RI FRQFOXVLYH HPSLULFDO VWXGLHV 6H\IULHG HW DO f &RFKOHDU ,PSODQWV &RFKOHDU LPSODQWV DUH VXUJLFDOO\ LPSODQWHG GHYLFHV WKDW GLUHFWO\ VWLPXODWH WKH LQQHU HDU DQG SURGXFH D VHQVDWLRQ RI VRXQG 7KH $G +RF &RPPLWWHH RQ &RFKOHDU ,PSODQWV +RSNLQV f OLVWHG HOHYHQ GLIIHUHQW W\SHV RI LPSODQWV ZKLFK DUH EHLQJ PDQXIDFWXUHG LQ WKH 8QLWHG 6WDWHV RU (XURSH KRZHYHU *LEVRQ f ZURWH WKDW WKHUH DUH UHSRUWHGO\ RYHU GLIIHUHQW FRFKOHDU LPSODQW GHYLFHV EHLQJ LQYHVWLJDWHG ZRUOGZLGH 'HVSLWH WKH QXPEHU RI LPSODQWV EHLQJ LQYHVWLJDWHG WKHLU EDVLF FRPSRVLWLRQ UHPDLQV WKH VDPH f PLFURSKRQH f VSHHFK SURFHVVRU f WUDQVPLWWHU FRLO f UHFHLYHU FRLO DQG f HOHFWURGHVf *LEVRQ f

PAGE 34

'LIIHUHQFHV LQ &RFKOHDU ,PSODQWV 7KH GLIIHUHQFHV LQ FRFKOHDU LPSODQWV FDQ EH GHVFULEHG E\ H[DPLQLQJ WKH IROORZLQJ IHDWXUHV f QXPEHU RI HOHFWURGHV f HOHFWURGH SRVLWLRQ DQG f VSHHFK SURFHVVLQJ VWUDWHJ\ 7KH HDUOLHVW DQG VLPSOHVW FRFKOHDU LPSODQW VWLOO HPSOR\HG WRGD\ KDG D VLQJOH HOHFWURGH VLQJOH FKDQQHOf +RXVH f 6RPH H[DPSOHV RI PXOWLHOHFWURGH RU PXOWLn FKDQQHO LPSODQWV FLWHG E\ *LEVRQ f DQG WKH $G +RF &RPPLWWHH +RSNLQV f LQFOXGHG WKH 6\PELRQ FKDQQHOVf A &KRULPDF FKDQQHOVf DQG 1XFOHXV FKDQQHOVf GHYLFHV 7KH FRQILJXUDWLRQ RI WKH HOHFWURGHV LQ WKH PXOWLFKDQQHO GHYLFHV GLIIHU EXW DV DOO VXEMHFWV LQ WKLV VWXG\ ZLOO EH ZHDULQJ WKH 1XFOHXV GHYLFH D GHVFULSWLRQ RI LWV HOHFWURGH FRQILJXUDWLRQ ZLOO EH JLYHQ LQ PRUH GHWDLO ODWHU LQ WKH FKDSWHU 7KH VHFRQG GLIIHUHQFH LQ FRFKOHDU LPSODQWV LV WKH HOHFWURGH SRVLWLRQLQJ $Q H[WUDFRFKOHDU HOHFWURGH PD\ EH SODFHG RQ WKH PHPEUDQH RI WKH URXQG ZLQGRZ WKLV W\SH EHLQJ LQYHVWLJDWHG E\ +RFKPDLU 09LHQQD LPSODQWf DQG )UDVHU )LQHWHFK51,'f DV FLWHG E\ *LEVRQ f ([DPSOHV RI LQWUDFRFKOHDU GHYLFHV LQFOXGH WKH 6\PELRQ WKH &KRULPDF DQG WKH 1XFOHXV *LEVRQ f 7KH WKLUG GLIIHUHQFH LQ LPSODQWV LV WKH VSHHFK SURFHVVLQJ VWUDWHJ\ 0DQ\ LPSODQWV XVH DQ DQDORJ VLJQDO ZKLFK LV EDQGSDVV ILOWHUHG IRU H[DPSOH WKH 0+RXVH VLJQDO

PAGE 35

LV ILOWHUHG EHWZHHQ DQG +] %RRWKUR\G f 7KLV .+] ILOWHUHG VLJQDO LV XVHG WR YDU\ WKH DPSOLWXGH RI D VLQXVRLGDO FDUULHU VLJQDO ZKLFK LV VHW MXVW EHORZ DXGLELOLW\ 7KHUH LV QR RWKHU SURFHVVLQJ DIWHU WKH DPSOLWXGH PRGXODWLRQ 7KH FOLQLFLDQ LV DEOH WR DGMXVW WKH FDUULHU OHYHO DQG OLPLW WKH PD[LPXP RXWSXW WKURXJK PDQLSXODWLRQ RI WKH SURFHVVRU FRQWUROV IRU HDFK SDWLHQW /LPLWLQJ RI WKH PD[LPXP RXWSXW LV E\ SHDN FOLSSLQJ 0RRUH DV FLWHG E\ .HVVOHU f UHIHUUHG WR WKLV W\SH RI SURFHVVLQJ DV WKH PRGXODWHGFDUULHU DQDORJ DSSURDFK GHILQLQJ LW DV D VWUDWHJ\ LQ ZKLFK WKH ZDYHIRUP LWVHOI LV XVHG WR GULYH WKH HOHFWURGH DQG LQ ZKLFK DQ DWWHPSW LV PDGH WR VTXHH]H WKH HQWLUH VSHHFK VLJQDO LQWR D VLQJOH FKDQQHO S f $QRWKHU W\SH RI VSHHFK SURFHVVLQJ DQG WKH RQH XVHG E\ WKH 1XFOHXV GHYLFH VHOHFWLYHO\ H[WUDFWV FRPSRQHQWV RI VSHHFK IURP WKH DFRXVWLF VLJQDO 7KH GLUHFWLRQDO PLFURSKRQH SLFNV XS VRXQGV DQG VHQGV WKH LQIRUPDWLRQ WR WKH VSHHFK SURFHVVRU 7KH VSHHFK SURFHVVRU ILOWHUV WKH VRXQG DQG H[WUDFWV IRUPDQW LQIRUPDWLRQ IURP WKH VSHHFK VLJQDO 7KDW LQIRUPDWLRQ SDVVHV WR D PDS ZKLFK LV WKH GLJLWDO PHPRU\ LQ WKH VSHHFK SURFHVVRU DQG LW LV KHUH WKDW WKH DSSURSULDWH HOHFWURGH FXUUHQW DPSOLWXGH DQG VWLPXOXV UDWH DUH DVVLJQHG 7KH VLJQDO LV FRGHG DQG WUDYHOV WKURXJK WKH VNLQ E\ D UDGLR IUHTXHQF\ VLJQDO WR WKH LPSODQWHG UHFHLYHU VWLPtODWRU /DVWO\ WKH UHFHLYHUVWLPXODWRU GHFRGHV WKH

PAGE 36

VLJQDO DOORZLQJ SDLUV RI WKH HOHFWURGHV WR EH VWLPXODWHG WR SURGXFH VSHHFKOLNH VRXQGV 7KH 1XFOHXV GHYLFH H[WUDFWV IXQGDPHQWDO IUHTXHQF\ )f IURP WKH VSHHFK RI WKH SHUVRQ DQG VHQGV WKDW LQIRUPDWLRQ WR WKH VSHDNHU E\ WKH UDWH RI VWLPXODWLRQ SXOVH 6LJQDO LQWHQVLW\ LQIRUPDW FRQYH\HG E\ WKH DPSOLWXGH RI WKH SXOVHV )LUVW ),f DQG VHFRQG )f IRUPDQW LQIRUPDWLRQ LV SURYLGHG IURP WKH SRVLWLRQ RI WKH HOHFWURGHV ,QLWLDOO\ WKH :HDUDEOH 6SHHFK 3URFHVVRU :63,,f SURYLGHG RQO\ )2 DQG ) LQIRUPDWLRQ ,Q DQRWKHU FRGLQJ VWUDWHJ\ :63,,,f SURYLGLQJ ))) LQIRUPDWLRQ EHFDPH DYDLODEOH 'RZHOO 6HOLJPDQ %ODUQH\ t &ODUN f ,Q WKLV FRGLQJ VWUDWHJ\ D EDVDO HOHFWURGH ZDV VWLPXODWHG IROORZHG LQ UDSLG VXFFHVVLRQ E\ VWLPXODWLRQ RI D PRUH DSLFDO HOHFWURGH \LHOGLQJ ) DQG ), 7KH DGGLWLRQ RI ), WR WKH SURFHVVLQJ VWUDWHJ\ ZRXOG EH H[SHFWHG WR IXUWKHU HQKDQFH YRZHO SHUFHSWLRQ DV WKRVH IRUPDQWV DUH NQRZQ WR EH FULWLFDO 0DF.D\ f 7KH PRVW UHFHQW GHYHORSPHQW LQ FRGLQJ VWUDWHJ\ EHFDPH DYDLODEOH LQ ZLWK WKH 0LQL 6SHHFK 3URFHVVRU 063f 6NLQQHU +ROGHQ 'RZHOO 6HOLJPDQ %ULPDFRPEH %HLWHU &ODUN f 7KH 063 HPSOR\V D PXOWLSHDN VWUDWHJ\ ZKLFK PHDVXUHV GRPLQDQW VSHFWUDO SHDNV IRU IUHTXHQF\ UDQJHV FRQWDLQLQJ ), +]f DQG ) +]f DV ZHOO DV WKH HQHUJ\ FRQWDLQHG LQ WKRVH IUHTXHQF\ EDQGV 7KHVH PHDVXUHPHQWV KDYH EHHQ $ DQG $ DQG FRUUHVSRQG WR ), DQG ) ,Q

PAGE 37

DGGLWLRQ WKUHH RWKHU IUHTXHQF\ FDQ EH DFWLYDWHG $ +=f $ +]f DQG $ +]f 3DWULFN t &ODUN f $ DQG $ DUH DOZD\V DFWLYDWHG DQG DFWLYDWLRQ RI WKH KLJKHU IUHTXHQF\ EDQGV LV GHSHQGHQW XSRQ WKH SDUWLFXODU DFRXVWLF VLJQDO EHLQJ VDPSOHG ,Q WKH FDVH RI XQYRLFHG VWLPXOL WKHUH LV D VPDOO DPRXQW RI HQHUJ\ LQ WKH ), IUHTXHQF\ UDQJH VR WKH HOHFWURGH IRU ), LV QRW VWLPXODWHG ,Q LWV SODFH WKH IL[HG HOHFWURGH IRU WKH $ EDQG LV DFWLYDWHG WKHUHE\ H[WUDFWLQJ KLJK IUHTXHQF\ LQIRUPDWLRQ &ODUN f 7KH RSSRVLWH LV WUXH IRU YRLFHG VWLPXOL 6LQFH WKHUH LV RQO\ D VPDOO DPRXQW RI KLJK IUHTXHQF\ HQHUJ\ LQ YRLFHG VWLPXOL WKH $ HOHFWURGH +]f LV QRW DFWLYDWHG 7KH DELOLW\ RI WKH VSHHFK SURFHVVRU WR SURYLGH WKH IUHTXHQF\ EDQGV $ $ $ LQ FRPELQDWLRQ ZLWK ))) LQIRUPDWLRQ SURYLGHV PRUH YRZHO DQG FRQVRQDQW LQIRUPDWLRQ ,Q DGGLWLRQ WR H[WUDFWLQJ LQIRUPDWLRQ LPSRUWDQW IRU XQGHUVWDQGLQJ VSHHFK 7KH HOHFWURGH FRQILJXUDWLRQ LV GHVLJQHG WR WDNH DGYDQWDJH RI WKH SK\VLRORJLFDO UHVSRQVH RI WKH FRFKOHD 7KLV LV DFFRPSOLVKHG E\ VWLPXODWLQJ GLVFUHWH DUHDV RI WKH EDVLODU PHPEUDQH 7KH FRQILJXUDWLRQ LV GHVFULEHG DV nfELSRODU %LSRODU HOHFWURGHV DUH VPDOO DQG DUH ORFDWHG DW HTXDO GLVWDQFHV IURP WKH WDUJHW QHUYH DQG VWLPXODWH GLVFUHWH DUHDV RI WKH FRFKOHD ,Q FRQWUDVW PRQRSRODU HOHFWURGHV DUH ODUJHU DQG WKH DFWLYH HOHFWURGH LV FORVHU WR WKH QHUYH WKDQ WKH JURXQG HOHFWURGH 0RQRSRODU

PAGE 38

HOHFWURGHV VWLPXODWH ODUJH JURXSV RI QHUYH FHOOV DQG DUH QRW HIIHFWLYH LQ SURYLGLQJ GLVFUHWH DUHDV RI VWLPXODWLRQ )UDYHO f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f 7KLV LV FRQVLVWHQW ZLWK ZKDW LV NQRZQ DERXW ORZ IUHTXHQF\ KHDULQJ ZKLFK LV FRGHG EDVHG RQ WKH SODFH RI PD[LPDO GLVFKDUJH DQG WKH SHULRGLFLW\ RI WKH GLVFKDUJH SDWWHUQ
PAGE 39

EDVLV DQG VKRXOG QRW EH JHQHUDOL]HG WR WKH SURIRXQGO\ GHDIHQHG SRSXODWLRQ DV D ZKROH S f 7KH FULWHULD VXJJHVWHG E\ WKH 1DWLRQDO ,QVWLWXWHV RI +HDOWK &RQVHQVXV 'HYHORSPHQW &RQIHUHQFH 6WDWHPHQW f LQFOXGH WKH IROORZLQJ f $XGLRORJLFDO &ULWHULD $f %LODWHUDO SURIRXQG VHQVRULQHXUDO KHDULQJ ORVV %f %LODWHUDO DLGHG WKUHVKROGV JUHDWHU WKDQ G% +/ &f SHUFHQW FRUUHFW RQ RSHQVHW VSHHFK UHFRJQLWLRQ 'f /DFN RI VXEVWDQWLDO LQFUHDVH LQ OLSUHDGLQJ ZLWK DSSURSULDWH DPSOLILFDWLRQ f (OHFWURSKYVLRORTLFDO &ULWHULD $f 0HDVXUHPHQW RI HDUO\ PLGGOH DQG ODWH ODWHQF\ HYRNHG SRWHQWLDOV %f $EVHQFH RI QHXUDO UHVSRQVHV PD\ RU PD\ QRW SURYH WR EH D FRQWUDLQGLFDWLRQ f 0HGLFDO 6XUJLFDO &ULWHULD $f 8VXDO FDQGLGDWH LV D SRVWOLQJXDO RQVHW KHDOWK\ DGXOW %f 3RVVLEOH FRPSOLFDWLQJ IDFWRUV LQFOXGH Lf $QDWRPLFDO SUREOHPV ZKLFK PD\ SUHFOXGH LQVHUWLRQ RI WKH HOHFWURGHVf LLf 3UHH[LVWLQJ HDU SUREOHPV

PAGE 40

f 3V\FKRSK\VLFDO &ULWHULD $f 1RQH RI WKH SV\FKRSK\VLFDO GDWD DYDLODEOH IRU H[DPSOH JDS GHWHFWLRQ DUH FRQVLGHUHG FULWLFDO WR WKH LVVXH RI FDQGLGDF\ DW WKLV WLPH %f 3V\FKRSK\VLFDO GDWD KDYH QRW EHHQ VKRZQ WR EH JRRG SUHGLFWRUV RI VSHHFK UHFRJQLWLRQ SHUIRUPDQFH f 3V\FKRORJLFDO DQG /LQJXLVWLF &ULWHULD $f 0RVW SV\FKRORJLFDO WHVWLQJ LV GRQH IRU H[FOXVLRQDU\ SXUSRVHV VXFK DV PHQWDO UHWDUGDWLRQ RU SV\FKLDWULF GLVRUGHUV S f 5LVNV DQG %HQHILWV RI &RFKOHDU ,PSODQWV $V ZLWK DQ\ VXUJLFDO SURFHGXUH DQG XVH RI JHQHUDO DQHVWKHVLD WKHUH DUH LQKHUHQW ULVNV WR WKH SDWLHQW 7KH ULVNV FLWHG E\ WKH $G +RF &RPPLWWHH 5HSRUW +RSNLQV f LQFOXGH f 7KH UHGXFWLRQ RU WRWDO ORVV RQ DQ\ SUHVXUJLFDO UHVLGXDO KHDULQJ f &RPSOLFDWLRQV GXH WR DQHVWKHVLD DQG VXUJHU\ f 3RVWVXUJLFDO ULVNV $f %LRLQFRPSDWLELOLW\ RI WKH LQWHUQDO FRPSRQHQWV %f ([WUDFRFKOHDU LQIHFWLRQV &f ,QWUDFRFKOHDU LQIHFWLRQV VHFRQGDU\ WR RWLWLV PHGLD

PAGE 41

'f )DFLDO QHUYH GDPDJHSDUDO\VLV (f 1HZ ERQH JURZWK ZLWKLQ WKH FRFKOHD )f ,QWUDFRFKOHDU VFDUULQJ DQG ILEURXV WLVVXH JURZWK *f 'HJHQHUDWLRQ RI VXUYLYLQJ QHUYH ILEHUV +f 8QNQRZQ UHDFWLRQV WR SURORQJHG VWLPXODWLRQ ,f 5HTXLUHG UHSODFHPHQW RI IDLOHG LQWHUQDO FRPSRQHQWV f 8QUHDOLVWLF H[SHFWDWLRQV RI FRFKOHDU LPSODQW DQG IDPLO\ OHDGLQJ WR SV\FKRORJLFDO GLVWXUEDQFHV f 3RVVLEOH YHVWLEXODU FRPSOLFDWLRQV f 3RVVLEOH H[DFHUEDWLRQ RI WLQQLWXV 3RVVLEOH EHQHILWV FLWHG E\ WKH FRPPLWWHH LQFOXGH f ,QFUHDVHG DZDUHQHVV RI VRXQG f LPSURYHG DELOLW\ WR PRQLWRU VSHHFK SURGXFWLRQ f 5HFRJQLWLRQ RI VRPH HYHU\GD\ VRXQGV f ,PSURYHG DZDUHQHVV RI VXUSUDVHJPHQWDO IHDWXUHV RI VSHHFK f 6XSSOHPHQW WR OLSUHDGLQJ f 3HUFHSWLRQ RI VRPH VHJPHQWDO DVSHFWV RI VSHHFK OHDGLQJ WR OLPLWHG ZRUG UHFRJQLWLRQ DQG XQGHUVWDQGLQJ RI VSHHFK f 5HGXFWLRQ RI WLQQLWXV

PAGE 42

f LPSURYHG VRFLDO LQWHUDFWLRQ DQG HPSOR\PHQW SRWHQWLDO f 6LJQLILFDQW ZRUG UHFRJQLWLRQ LQ VHQWHQFHV LQ VRXQGDORQH FRQGLWLRQV S f $XUDO 5HKDELOLWDWLRQ ,VVXHV $XUDO UHKDELOLWDWLRQ RI WKH FRFKOHDU LPSODQW SDWLHQW EHJLQV ZLWK WKH HYDOXDWLRQ SURFHGXUHV HPSOR\HG GXULQJ WKH VHOHFWLRQ SURFHVV /DQVLQJ f KDV GLYLGHG WKH UHKDELOLWDWLRQ SURFHVV LQWR WKUHH DUHDV f GHYHORSPHQW RI UHDOLVWLF H[SHFWDWLRQV IRU WKH LPSODQW f WUDLQLQJ LQ WKH LQWHUSUHWDWLRQ DQG XVH RI WKH QHZ DXGLWRU\ LQIRUPDWLRQ ZLWK DQG ZLWKRXW YLVXDO FXHV DQG f GHYHORSPHQW RI FRSLQJ VWUDWHJLHV WR HQKDQFH FRPPXQLFDWLRQ 6RPH RI WKH YDULDELOLW\ RI UHVSRQVHV IURP SDWLHQWV QR GRXEW LV GXH WR WKHLU LQGLYLGXDO GLIIHUHQFHV KRZHYHU VRPH PD\ EH GXH WR WKH GLIIHUHQFHV LQ SURWRFRO DPRQJ WKH FHQWHUV :KLOH PRVW FHQWHUV RIIHU FRXQVHOLQJ RQJRLQJ DGMXVWPHQW RI WKH GHYLFH GLUHFW WUDLQLQJ DQG PHDVXUHV RI SHUIRUPDQFH RWKHUV RQO\ SURYLGH FRXQVHOLQJ DQG DGMXVWPHQW WR WKH LPSODQW +RSNLQV f 2WKHUV OLNH WKH +RXVH (DU ,QVWLWXWH DQG WKH FHQWHUV LPSODQWLQJ 1XFOHXV GHYLFHV KDYH VSHFLILHG H[WHQVLYH SURWRFROV IRU DGMXVWLQJ WKH LPSODQW DQG WUDLQLQJ WKH SDWLHQWV WR XVH WKH GHYLFH 7KH TXHVWLRQ RI GHJUHH RI HIIHFWLYHQHVV RI WKH LPSODQW YHUVXV HIIHFWLYHQHVV RI WKH WUDLQLQJ UHPDLQV DQ LVVXH LQ QHHG RI IXUWKHU VWXG\

PAGE 43

6SHHFK 3HUFHSWLRQ 6WXGLHV RI &RFKOHDU ,PSODQW 8VHUV 6SHHFK SHUFHSWLRQ VWXGLHV ZLWK WKH LPSODQW LQFOXGLQJ ERWK VLQJOH DQG PXOWLFKDQQHO KDYH EHHQ DQ DUHD RI ZLGH LQWHUHVW WR WKH UHVHDUFK FRPPXQLW\ %LOJHU (GGLQJWRQ (LVHQEHUJ HW DO +ROPHV .HPNHU t 0HUZLQ f 7KH SHUFHSWLRQ RI VSHHFK XVLQJ DXGLWRU\ FXHV RQO\ KDV EHHQ VHHQ LQ VRPH SDWLHQWV DQG KDV UHFHQWO\ EHHQ UHSRUWHG IRU VRPH FKLOGUHQ %HUOLQHU 7RQRNDZD '\H t +RXVH f HYDOXDWHG SURIRXQGO\ KHDULQJLPSDLUHG FKLOGUHQ RYHU WKH DJH RI \HDUV $OO WKH FKLOGUHQ ZHUH LPSODQWHG ZLWK WKH 0+RXVH VLQJOHFKDQQHO GHYLFH 7KHLU DJHV DW WKH WLPH RI WKH VWXG\ UDQJHG IURP WR \HDUV ZLWK DYHUDJH DJH DW WKH RQVHW RI GHDIQHVV RI \HDUV $JH DW WKH WLPH RI UHFHLYLQJ WKH LPSODQW UDQJHG IURP WR \HDUV ZLWK D PHDQ RI \HDUV 7HVW PDWHULDOV ZHUH DGPLQLVWHUHG XVLQJ OLYHYRLFH DW D QRUPDO FRQYHUVDWLRQ OHYHO 3RUWLRQV RI WKH *OHQGRQDOG $XGLWRU\ 6FUHHQLQJ 3URFHGXUH *$63f (UEHU f ZHUH DGPLQLVWHUHG WR DVVHVV RSHQVHW VSHHFK UHFRJQLWLRQ 7KH DXWKRUV QRWHG WKDW WKH *$63 LV GHVLJQHG DV D FORVHGVHW WHVW LH SLFWXUH SRLQWLQJ WDVN KRZHYHU IRU WKLV VWXG\ LW ZDV DGPLQLVWHUHG DXGLWRULO\ RQO\ 7KH FKLOGUHQ ZHUH WHVWHG ZLWK ZRUG DQG VHQWHQFH VWLPXOL XVLQJ DQ DXGLWRU\ PRGH RQO\ 7KH\ UHSRUWHG WKDW SHUFHQW RI WKH FKLOGUHQ GHPRQVWUDWHG VRPH RSHQVHW GLVFULPLQDWLRQ RQ WKH ZRUG LGHQWLILFDWLRQ 6HQWHQFH FRPSUHKHQVLRQ VFRUHV ZHUH SHUFHQW 7KH GXUDWLRQ RI

PAGE 44

GHDIQHVV ZDV QRWHG WR EH VKRUWHU IRU FKLOGUHQ DEOH WR VFRUH RQ WKH RSHQVHW GLVFULPLQDWLRQ WDVN WKDQ IRU WKRVH ZKR ZHUH XQDEOH WR GR VR %HUOLQHU HW DO f DOVR FLWHG D VWXG\ E\ *HHUV DQG 0RRJ LQ SUHVVf LQ ZKLFK WKH\ DVVHVVHG RI KLJKSHUIRUPLQJ FKLOGUHQ XVLQJ WKH 0+RXVH GHYLFH WKH\ DOVR UHSRUWHG WKDW RI WKH FKLOGUHQ LQ WKH VWXG\ DFKLHYHG VRPH RSHQVHW DXGLWRU\RQO\ UHFRJQLWLRQ RI VLPSOH 'RUPDQ HW DO f LQYHVWLJDWHG WKH DELOLW\ RI SDWLHQWV XVLQJ WKH 6\PELRQ PXOWLFKDQQHO LPSODQW WR LGHQWLI\ D V\QWKHWLF YRZHOV (LJKW VXEMHFWV SDUWLFLSDWHG LQ WKH VWXG\ DOO DW OHDVW \HDUV ROG 7KH OHQJWK RI GHDIQHVV UDQJHG IURP \HDU WR \HDUV ZLWK D PHDQ RI \HDUV 7KH UHVXOWV RI WKLV VWXG\ LQGLFDWHG WKDW DOO HLJKW VXEMHFWV VFRUHG DERYH SHUFHQW FRUUHFW RQ D WHVW RI VSRQGHH ZRUG LGHQWLILFDWLRQ 7ZHOYH V\QWKHWLF YRZHOV LQ WKH EYW IRUPDW FRPSULVHG WKH VWLPXOL 9RZHOV FKDUDFWHUL]HG E\ ORZ ), DQG ) IRUPDQWV ZHUH ZHOO LGHQWLILHG ZKHUHDV WKRVH ZLWK KLJK ), DQG ORZ ) IRUPDQWV ZHUH QRW ZHOO LGHQWLILHG 7KH DXWKRUV FRQFOXGHG WKDW WKHLU UHVXOWV ZHUH FRQVLVWHQW ZLWK WKH PRGHO RI ), EHLQJ VSHFLILHG E\ D UDWH FRGH DQG H[WUHPH YDOXHV RI ) VSHFLILHG E\ D UDWHSODFH FRGH :DOW]PDQ DQG +RFKEHUJ f LQYHVWLJDWHG WKH SHUFHSWLRQ RI VSHHFK SDWWHUQ FRQWUDVWV LQ SDWLHQWV XVLQJ WKH 1XFOHXV GHYLFH LQ HLWKHU DQ )) FRGLQJ VWUDWHJ\ 1 f RU DQ ))) 1 f VWUDWHJ\ 6XEMHFWV LQ WKLV VWXG\ UDQJHG

PAGE 45

LQ DJH IURP WR ZLWK D PHDQ DJH RI \HDUV 7KH 6SHHFK 3DWWHUQ &RQWUDVW 63$&f WHVW %RRWKUR\G f ZDV XVHG WR HYDOXDWH WKH SHUFHSWLRQ RI VSHHFK SDWWHUQ FRQWUDVWV E\ WKH VXEMHFWV 7KLV WHVW HYDOXDWHV WKH SHUFHSWLRQ RI IRXU VXSUDVHJPHQWDO DQG HLJKW VHJPHQWDO VSHHFK FRQWUDVWV ,W LV D IRUFHGFKRLFH IRUPDW XVLQJ UHDO ZRUGV SKUDVHV DQG 7KH UHVXOWV RI WKLV LQYHVWLJDWLRQ LQGLFDWHG WKDW ERWK SURFHVVLQJ VWUDWHJLHV SURYLGHG VXIILFLHQW LQIRUPDWLRQ DERXW VSHHFK FRQWUDVWV HVSHFLDOO\ IXQGDPHQWDO IUHTXHQF\ WHPSRUDO DQG LQWHQVLW\ FXHV /DVWO\ 7\H0XUUD\ DQG 7\OHU f LQYHVWLJDWHG DXGLWRU\ FRQVRQDQW DQG ZRUG UHFRJQLWLRQ VNLOOV RI VXEMHFWV WZR ZRUH 0+RXVH LPSODQWV WKUHH ZRUH 09LHQQD LPSODQWV VHYHQ ZRUH 1XFOHXV LPSODQWV DQG ZRUH 6\PELRQ LPSODQWV 7KH VSHHFK PDWHULDOV FRQVLVWHG RI FRQVRQDQWV LQ DQ L&L FRQWH[W DQG WKH 6HQWHQFH 7HVW :LWKRXW 9HUVLRQ 7\OHU /DQVLQJ t 3UHHFH f 7KHLU FRQFOXVLRQV ZHUH DV IROORZV f 0RVW VXEMHFWV UHFRJQL]HG FRQVRQDQWV LQ DQ DXGLWLRQRQO\ FRQGLWLRQ DW DERYH FKDQFH OHYHO f 6XEMHFWV SHUFHLYH WKH HQYHORSH IHDWXUH UHODWLYHO\ ZHOO DQG WKH SODFH IHDWXUH UHODWLYHO\ SRRUO\ f 7KH YRLFLQJ QDVDOLW\ GXUDWLRQ DQG HQYHORSH IHDWXUH ZHUH EHWWHU XWLOL]HG IRU FRQVRQDQW UHFRJQLWLRQ E\ VXEMHFWV ZHDULQJ WKH 6\PELRQ GHYLFH WKDQ VXEMHFWV ZHDULQJ WKH 1XFOHXV ))f GHYLFH

PAGE 46

f f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f 2QH VWXG\ GHVLJQHG VSHFLILFDOO\ WR LQYHVWLJDWH WKH HIIHFW RI WKH VLQJOH FKDQQHO FRFKOHDU LPSODQW RQ YRLFH SDUDPHWHUV ZDV UHSRUWHG E\ .LUN DQG (GJHUWRQ f 7KH VXEMHFWV ZHUH WZR PHQ DQG WZR ZRPHQ DJHV WR \HDUV 6SHHFK VDPSOHV RI WKH VXEMHFWV UHDGLQJ WKH 5DLQERZ 3DVVDJH ZLWK WKH LPSODQW RII DQG RQ ZHUH REWDLQHG IURP WKH XVHUV DQG QRUPDOKHDULQJ FRQWURO VXEMHFWV 7KH UHVXOWV LQGLFDWHG WKDW PDOHV KDG D WHQGHQF\ WR VSHDN ZLWK ORZHU )2 ZKHQ WKH LPSODQW ZDV RQ DQG ZLWK UHGXFHG YDULDELOLW\ RI YRRDO LQWHQVLW\

PAGE 47

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f 7KHLU VXEMHFWV KDG EHHQ MXGJHG DV VXFFHVVIXO LPSODQW XVHUV EDVHG RQ WKHLU VSHHFK UHFRJQLWLRQ DELOLW\ ZLWK RQO\ WKH LPSODQW DQG WKHLU H[FHOOHQW VHQWHQFH SHUFHSWLRQ XVLQJ WKH LPSODQW ZLWK OLSUHDGLQJ 7KHLU VXEMHFWV KDG EHFRPH GHDI DW WKH DJHV RI DQG \HDUV UHVSHFWLYHO\ 7KH\ KDG UHFHLYHG WKHLU LPSODQWV DW DJHV DQG UHVSHFWLYHO\ 7KH SXUSRVH RI WKH VWXG\ ZDV WR HYDOXDWH WKHLU SUH DQG SRVWLPSODQW VSHHFK SURGXFWLRQ DV GHILQHG E\ LQWHOOLJLELOLW\ %RRWKUR\GnV 6SHHFK 3HUFHSWLRQ &RQWUDVW 63$&f WHVW ZDV XVHG WR PHDVXUH WKH LQWHOOLJLELOLW\ RI SKRQHWLF FRQWUDVWV :KLOH WKH WHVW ZDV RULJLQDOO\ GHVLJQHG WR PHDVXUH VSHHFK SHUFHSWLRQ WKH DXWKRUV QRWHG WKDW %RRWKUR\G KDV DOVR VKRZQ WKLV WHVW WR EH HTXDOO\ HIIHFWLYH LQ DVVHVVLQJ VSHHFK SURGXFWLRQ 7KH WHVW PDWHULDO ZDV UHFRUGHG E\ HDFK RI WKH

PAGE 48

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f UHSRUWHG FKDQJHV LQ WKH VSHHFK SURGXFWLRQ RI WHQ SRVWOLQJXDO 6ZHGLVK SDWLHQWV ZKR UHFHLYHG WKH 09LHQQD H[WUDFRFKOHDU VLQJOHFKDQQHO GHYLFH ZDV FRQGXFWHG DIWHU PRQWKV RI LPSODQW XVH 7KH UHVHDUFK 7KH SDWLHQWV KDG YDU\LQJ FDXVHV RI KHDULQJ ORVV DQG WKHLU DJHV UDQJHG IURP \HDUV ROG 5HFRUGLQJV ZHUH PDGH RI WKH VXEMHFWVn UHDGLQJ D VWDQGDUG SDVVDJH RI ZRUGV S f 7KH VXEMHFWV UHDG SULRU WR UHFHLYLQJ WKH LPSODQW DQG DW RQH WKUHH VL[ WZHOYH HLJKWHHQ PRQWKV SRVWLPSODQW )LYH RI WKHP PDGH DQRWKHU UHFRUGLQJ DW WZHQW\IRXU PRQWKV 7KH UHVXOWV LQGLFDWHG WKDW PRVW RI WKH VXEMHFWV ZHUH ZLWKLQ

PAGE 49

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f ZHUH QRW IRXQG LQ WKHVH VXEMHFWV 7ZR H[SODQDWLRQV ZHUH RIIHUHG IRU WKLV ODFN RI UHVSRQVH f \HDUV RI WRWDO GHDIQHVV KDG UHVXOWHG LQ SDWLHQWV OHDUQLQJ WR UHO\ RQ WDFWLOH IHHGEDFN DQG f )2 DQG GXUDWLRQDO DXGLWRU\ FXHV DV EDFNJURXQG QRLVH DQG GR QRW LQIOXHQFH DUWLFXODWLRQ 'HOD\HG $XGLWRU\ )HHGEDFN 'HOD\HG DXGLWRU\ IHHGEDFN '$)f LV D FRQGLWLRQ LQ ZKLFK WKHUH LV DQ H[SHULPHQWDOO\ LQGXFHG WLPH GHOD\ LQ D VSHDNHU

PAGE 50

KHDULQJ WKHLU RZQ YRLFH 1RUPDOO\ DV SHRSOH VSHDN WKH\ KHDU WKHLU RZQ YRLFHV ZLWKLQ DSSUR[LPDWHO\ RQH PLOOLVHFRQG
PAGE 51

)DLUEDQNV f SURSRVHG D PRUH HODERUDWH FORVHGORRS PRGHO RU VHUYRV\VWHP RI VSHHFK SURGXFWLRQ EDVHG RQ DXGLWRU\ PRQLWRULQJ DQG LOOXVWUDWHG KLV PRGHO ZLWK VWXGLHVn XWLOL]LQJ '$) +LV PRGHO LQFOXGHG D VHQVRU XQLW ZKLFK IHG DXGLWRU\ WDFWLOH DQG SURSULRFHSWLYH LQIRUPDWLRQ EDFN WR WKH FRPSDUDWRU XQLW LQIRUPDWLRQ FRPSDUHG WR WKH RXWSXW DQG WKH FRPSDUDWRU LGHQWLILHG DQ\ GLVFUHSDQFLHV EHWZHHQ WKH WZR VLJQDOV +H QRWHG WKDW WKH GHOD\HG DXGLWRU\ IHHGEDFN FRQGLWLRQ PLVLQIRUPV WKH V\VWHP DERXW LWV VXFFHVV LQ HIIHFWLQJ DQG LQ RUGHULQJ LWV LQWHQGHG RXWSXW XQLWV WKXV LPSDLULQJ LWV EDVLF SURGXFH S f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f LQYHVWLJDWHG IXUWKHU WKH HIIHFWV RI '$) RQ DUWLFXODWLRQ

PAGE 52

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b RI WKRVH ZHUH UHSHWLWLYH 7KH DXWKRUV QRWHG WKDW WKH UHSHWLWLRQV ZHUH QRW SULPDULO\ FRUUHFWLYH EXW UDWKHU D SXUSRVHOHVV UHVSRQVH 7KH DPRXQW RI GHOD\ ZKLFK LV PRVW GLVUXSWLYH KDV EHHQ VKRZQ WR YDU\ DV D IXQFWLRQ RI DJH ZLWK WKH GHOD\ QHFHVVDU\ WR GLVUXSW VSHHFK GHFUHDVLQJ ZLWK DJH 0DF.D\ 6LHJHO )HQVW *DUEHU t 3LFN f 0DQ\ UHVHDUFKHUV %ODFN )DLUEDQNV 0DF.D\ %X[WRQ +DUULQJWRQ f KDYH UHSRUWHG WKDW EHWZHHQ DQG LOOLVHFRQGV SURGXFHV WKH PRVW GLVUXSWLRQ WR WKH VSHHFK RI DGXOWV ZLWK WKH H[FHSWLRQ RI ROGHU DGXOWV WR \HDUV ROGf ZKR H[SHULHQFH PD[LPDO GLVUXSWLRQ RI WKHLU VSHHFK DW PLOOLVHFRQGV %X[WRQ f 'LIIHUHQFHV UHODWHG WR JHQGHU DUH QRW DV FOHDU DV WKRVH 6RPH UHVHDUFKHUV KDYH IRXQG GLIIHUHQFHV ZLWK PDOHV PRUH RIWHQ DIIHFWHG WKDQ IHPDOHV 7LPPRQV

PAGE 53

7LPPRQV t %RXGUHDX f KRZHYHU %X[WRQ f UHSRUWHG QR GLIIHUHQFHV 7KH GHPRQVWUDWHG '$) HIIHFW KDV EHHQ LQWHUSUHWHG E\ PDQ\ UHVHDUFKHUV DV HYLGHQFH WKDW VSHHFK DFWV DV D VHUYRPHFKDQLVP DQG DXGLWRU\ IHHGEDFN LV WKH SULPDU\ FRQWURO FKDQQHO %RUGHQ t +DUULV f +RZHYHU %RUGHQ DQG +DUULV f DOVR QRWHG WKDW WKLV YLHZ KDV EHHQ FKDOOHQJHG E\ WKRVH ZKR SRLQW RXW WKDW WKH '$) HIIHFW FDQ IRU H[DPSOH EH RYHUULGGHQ LI WKH VSHDNHU DWWHQGV WR WKH UHDGLQJ DQG LJQRUHV WKH DFRXVWLF LQIRUPDWLRQ EHLQJ UHFHLYHG ,Q DGGLWLRQ HDVXUHV RWKHU WKDQ '$) ZLOO LQWHUIHUH ZLWK VSHHFK SURGXFWLRQ IRU H[DPSOH DPSOLI\LQJ WKH DLU FRQGXFWHG VRXQG ZLOO FDXVH VSHDNHUV WR GHFUHDVH WKHLU YRFDO LQWHQVLW\ 6LHJHO t 3LFN f DWWHQXDWLQJ WKH DLU FRQGXFWHG VRXQG ZLOO SURGXFH WKH RSSRVLWH HIIHFW DQG LI OLVWHQHUV DUH XQDEOH WR KHDU WKHLU VSHHFK DW DOO WKH\ ZLOO LQFUHDVH WKHLU YRFDO LQWHQVLW\ DQG SURORQJ YRLFLQJ /DQH t 7UDQHO f )LQDOO\ %RUGHQ DQG +DUULV f VXJJHVWHG WKDW DXGLWLRQ DV D IHHGEDFN PHFKDQLVP IRU PRQLWRULQJ RQJRLQJ IOXHQW VSHHFK SURGXFWLRQ GRHV QRW SURYLGH D FRPSOHWH H[SODQDWLRQ EHFDXVH IRU PDQ\ WUDQVLHQW VRXQGV LW SURYLGHV LQIRUPDWLRQ WR WKH VSHDNHU WRR ODWH KH KDV DOUHDG\ VSRNHQ DQG FDQ RQO\ PDNH FRUUHFWLRQV DIWHU WKH IDFW S f +RZHYHU WKHUH ZDV DJUHHPHQW WKDW VSHDNHUV GR XVH DXGLWLRQ WR VKDUSHQ WKHLU VSHHFK VRXQG WDUJHWV DQG WKDW ZKHQ WKHUH LV LQWHUIHUHQFH

PAGE 54

ZLWK DXGLWRU\ IHHGEDFN WKH\ ZLOO WU\ WR RYHUFRPH LW E\ DWWHPSWLQJ WR FRUUHFW WKHLU VSHHFK RXWSXW +DUULQJWRQ f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f 7KH VSHDNHUnV DWWHPSW WR FRUUHFW WKH PLVPDWFK UHVXOWV LQ WKH RQVHW RI G\VIOXHQW VSHHFK ,Q DQ HIIRUW WR VWXG\ DXGLWRU\ UHOLDQFH 0D[RQ %UDFNHWW 5LRUGDQ DQG 3IHIIHU f VWXGLHG WKH HIIHFW RI '$) RQ KHDULQJLPSDLUHG FKLOGUHQ 'DWD ZHUH REWDLQHG RQ FKLOGUHQ DOO RI ZKR KDG D PHDQ OHQJWK RI XWWHUDQFH RI DW OHDVW $OO RI WKHLU VXEMHFWV ZHUH HQUROOHG LQ

PAGE 55

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nV IOXHQW VSHHFK SURGXFWLRQ 6XPPDU\ 7KH LPSRUWDQFH RI DXGLWRU\ IHHGEDFN WR WKH QRUPDO DFTXLVLWLRQ RI VSHHFK DQG ODQJXDJH LV XQTXHVWLRQHG +RZHYHU WKHUH DUH GLIIHULQJ YLHZV DV WR LWV GHJUHH RI LPSRUWDQFH LQ PDLQWHQDQFH RI QRUPDO VSHHFK SURGXFWLRQ IRU WKH DGYHQWLWLRXVO\ SURIRXQGO\ KHDULQJLPSDLUHG &RZLH t 'RXJODV&RZLH *RHKO t .DXIPDQ =LPPHUPDQ t 5HWWDOLDWD f 0DQ\ RI WKLV SRSXODWLRQ H[SHULHQFH VLJQLILFDQW FKDQJHV LQ VSHHFK SURGXFWLRQ 7KHVH FKDQJHV RFFXU RYHU WLPH DQG FDQ UDQJH IURP PLOG WR VHYHUH LQ DIIHFWLQJ WKH SHUVRQnV LQWHOOLJLELOLW\ 0DQ\ RI WKLV VDPH SRSXODWLRQ GR QRW UHFHLYH EHQHILW IURP FRQYHQWLRQDO

PAGE 56

DPSOLILFDWLRQ $ FRFKOHDU LPSODQW LV WKH RQO\ W\SH RI GHYLFH DYDLODEOH ZKLFK KDV WKH FDSDELOLW\ RI SURYLGLQJ DXGLWRU\ IHHGEDFN WR WKHP 6RPH VWXGLHV RI VSHHFK SHUFHSWLRQ LQ FRFKOHDU LPSODQW XVHUV KDYH UHSRUWHG LPSURYHPHQW LQ ORXGQHVV FRQWURO DQG YRLFH TXDOLW\ DQG KDYH DWWULEXWHG WKH LPSURYHPHQW WR WKH UHHVWDEOLVKHG DXGLWRU\ IHHGEDFN &KRXDUG HW DO (QJHOPDQQ HW DO )RXUFLQ HW DO f 7KH DUHD RI VSHHFK SURGXFWLRQ LQ WKH DGYHQWLWLRXVO\ GHDIHQHG FRFKOHDU LPSODQW XVHU KDV QRW EHHQ H[WHQVLYHO\ VWXGLHG ,W LV DQ DUHD QHHGLQJ IXUWKHU VWXG\ WR GRFXPHQW WKH HIIHFWLYHQHVV RI WKH UHHVWDEOLVKHG DXGLWRU\ IHHGEDFN V\VWHP DQG WR EHJLQ WR HYDOXDWH LWV HIIHFWLYHQHVV 'HOD\HG DXGLWRU\ IHHGEDFN RIIHUV D WRRO IRU PDNLQJ REMHFWLYH PHDVXUHV RI WKH FRFKOHDU LPSODQW XVHUV VSHHFK SURGXFWLRQ ZLWK DQG ZLWKRXW WKH LPSODQW r

PAGE 57

&+$37(5 ,,, 0(7+2'2/2*< 7KH SURFHGXUHV LQ WKLV VWXG\ ZHUH GHVLJQHG WR DVFHUWDLQ ZKHWKHU WKHUH LV D GHOD\HG DXGLWRU\ IHHGEDFN '$)f HIIHFW RQ WKH VSHHFK SURGXFWLRQ RI SRVWOLQJXDO FRFKOHDU LPSODQW 6SHFLILFDOO\ WKH SDUDPHWHUV PHDVXUHG IRU HYLGHQFH RI D '$) HIIHFW ZHUH Df UHDGLQJ UDWH DV PHDVXUHG LQ WRWDO WLPH WR UHDG WKH *UDQGIDWKHU 3DVVDJH Ef VSHHFK GXUDWLRQ DV PHDVXUHG LQ WRWDO WLPH WR FRXQW EDFNZDUGV IURP WR DQG Ff WRWDO QXPEHU RI FRQVRQDQW DQG YRZHO HUURUV LQ UHDGLQJ DQG FRXQWLQJ EDFNZDUGV 7KH FRFKOHDU LPSODQW XVHUVn VSHHFK ZDV UHFRUGHG LQ WKH SUHVHQFH DQG DEVHQFH RI '$) ZLWK WKHLU FRFKOHDU LPSODQW VSHHFK SURFHVVRU RII DQG RQ ,Q DGGLWLRQ D WKLUG H[SHULPHQWDO FRQGLWLRQ ZDV LQYHVWLJDWHG XVLQJ FRQYHQWLRQDO DPSOLILFDWLRQ LQ WKH XQLPSODQWHG HDU 6XEMHFWV (LJKW VXEMHFWV SDUWLFLSDWHG LQ WKLV VWXG\f§ILYH ZRPHQ DQG WKUHH PHQ $OO KDG FRPSOHWHG WKH UHFRPPHQGHG QXPEHU RI SRVWLPSODQW DXUDO UHKDELOLWDWLRQ VHVVLRQV DQG DOO ZHUH ZHDULQJ WKH 0HOERXUQH &RFKOHDU &RUSRUDWLRQf PXOWLFKDQQHO HOHFWURGH DUUD\ 1XFOHXVf LPSODQW DW WKH WLPH RI WKH VWXG\ 7KHUH ZDV QR VHOHFWLRQ EDVHG RQ JHQGHU DQGRU UDFH 7KH

PAGE 58

VXEMHFWV UDQJHG LQ DJH IURP WR \HDUV ZLWK D PHDQ RI 5HSRUWHG KHDULQJ ORVV HWLRORJLHV LQFOXGHG HQLQJLWLV QRLVH 0HQLQHUHnV 6\QGURPH DQG IRXU ZLWK QR NQRZQ HWLRORJ\ 2QH RI WKHVH XQNQRZQ HWLRORJLHV ZDV VXVSHFWHG WR EH &RJDQnV 6\QGURPH 8QDLGHG SXUH WRQH DYHUDJHV +]f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

PAGE 59

7DEOH 6XEMHFW ,QIRUPDWLRQ 6XEMHFW ,QIRUPDWLRQ *HQGHU )HPDOH )HPDOH )HPDOH 0DOH 0DOH 0DOH )HPDOH )HPDOH (WLRORJ\ "&RJDQnV 6\QGURPH 0HQLQJLWLV 8QNQRZQ 0HQLQJLWLV 1RLVH 7UDXPD 8QNQRZQ 0HQLQHUnV 6\QGURPH 8QNQRZQ $JH DW 2QVHW RI +HDULQJ /RVV \UVf $JH :KHQ ,PSODQWHG \UVf ,PSODQWHG (DU /HIW 5LJKW /HIW 5LJKW /HIW 5LJKW 5LJKW /HIW RI 3URJUDPPHG (OHFWURGHV (OHFWURGHV (OLPLQDWHG 6WLPXODWLRQ 0RGH %3 %3 &* %3 %3 %3 %3 %3 (QFRGHU 6WUDWHJ\ ))) ))) ))) 03($. 03($. f 03($. ))) 03($. $YHUDJH 'DLO\ :HDULQJ 7LPH KUVf 0RQWKV RI ,PSODQW ([SHULHQFH

PAGE 60

r REWDLQ KHU HYDOXDWLRQ RI HDFK VXEMHFWVn IDPLO\ VXSSRUW 7KH PDMRULW\ RI VXEMHFWV UHSRUWHGO\ HQMR\HG D JRRGf IDPLO\ VXSSRUW V\VWHP VXEMHFW SHUIRUPDQFH XVLQJ WKH LPSODQW HDFK ZDV JLYHQ WZR VXEWHVWV WKH &KRLFH 6SRQGHH 7HVW DQG VHQWHQFHV IURP WKH &,' (YHU\GD\ 6HQWHQFH 7HVW IURP 7KH 0LQLPDO $XGLWRU\ &DSDELOLWLHV %DWWHU\ 2ZHQV .HVVOHU 7HOOHHQ t 6FKXEHUW f 7KHVH PDWHULDOV DQG WKH WHVW FRQILJXUDWLRQ ZHUH VHOHFWHG EDVHG RQ WKH &RFKOHDU &RUSRUDWLRQ WHVW SURWRFRO IRU LQGLYLGXDOV UHFHLYLQJ WKHLU GHYLFH 6FRULQJ IRU ERWK WHVWV ZDV EDVHG RQ D SHUFHQWDJH FRUUHFW VFRUH 7KH SHUFHQWDJH FRUUHFW VFRUH IRU WKH VHQWHQFHV ZDV EDVHG RQ NH\ ZRUG VFRULQJ %RWK WHVWV ZHUH DGPLQLVWHUHG XVLQJ RQO\ DXGLWRU\ r FXHV RQO\ ZLWK WKH VSHHFK SURFHVVRU ZRUQ DW LWV XVXDO VHWWLQJ 7KH WHVWV ZHUH DGPLQLVWHUHG LQ D VRXQGWUHDWHG DXGLRORJLFDO WHVW VXLWH LQ VRXQG ILHOG ZLWK WKH VXEMHFW IDFLQJ WKH RXWSXW VSHDNHU DW D GLVWDQFH RI RQH PHWHU 7KH PDWHULDO ZDV SUHVHQWHG DW DQ LQWHQVLW\ RI G% 63/ 5HVXOWV RI WKHVH WHVWV FDQ EH IRXQG LQ 7DEOH 7R REWDLQ D VXEMHFWLYH HVWLPDWH RI SHUIRUPDQFH XVLQJ WKH LPSODQW WKH VXEMHFWV ZHUH DVNHG WR FRPSOHWH WKH 3HUIRUPDQFH ,QYHQWRU\ IRU 3URIRXQG DQG 6HYHUH /RVV 3,36/f 2ZHQV t 5DJJLR f 7KH 3,36/ PHDVXUHV D SHUVRQnV SHUFHSWLRQ RI WKHLU FRPPXQLFDWLYH SHUIRUPDQFH DQG LW LV HVSHFLDOO\ GHVLJQHG IRU WKH LQGLYLGXDO ZLWK VHYHUH DQGRU

PAGE 61

7DEOH 3HUFHQWDJH FRUUHFW UHVXOWV REWDLQHG RQ WKH &KRLFH 6SRQGHH DQG WKH &,' (YHU\GD\ 6HQWHQFHV 7HVWV &KRLFH 6SRQGHH &,' (YHU\GD\ 6HQWHQFHVr 6V b &RUUHFW b &RUUHFW r 7HQ VHQWHQFHV ZHUH SUHVHQWHG

PAGE 62

SURIRXQG KHDULQJ ORVV ,W FRQVLVWV RI ZULWWHQ UHVSRQVHV WR LWHPV IURP VL[ GLIIHUHQW f f 8QGHUVWDQGLQJ 6SHHFK ZLWK 9LVXDO &XHV ZKLFK HYDOXDWHV WKH DELOLW\ WR XQGHUVWDQG FRQQHFWHG VSHHFK ZKHQ WKH VSHDNHUnV IDFH LV YLVLEOH ,QWHQVLW\ ZKLFK GHVFULEHV WKH SHUVRQnV DELOLW\ WR GHWHFW HYHU\GD\ VRXQGV DQG WKHLU UHODWLYH ORXGQHVV f f 5HVSRQVH WR $XGLWRU\ )DLOXUH ZKLFK DGGUHVVHV KRZ WKH SHUVRQ PDQDJHV FRPPXQLFDWLRQ EUHDNGRZQV (QYLURQPHQWDO 6RXQGV ZKLFK DGGUHVVHV LVVXHV RI f UHFRJQL]LQJ IDPLOLDU VRXQGV DXGLWRULO\ RQO\ 8QGHUVWDQGLQJ 6SHHFK ZLWK 1R 9LVXDO &XHV ZKLFK HYDOXDWHV VSHHFK XQGHUVWDQGLQJ ZLWKRXW YLVXDO FXHV DQG f 3HUVRQDO GHVLJQHG WR HOLFLW WKH SDWLHQWnV IHHOLQJV DERXW WKHLU KHDULQJ ORVV 7ZR RWKHU FDWHJRULHV 2FFXSDWLRQ DQG *HQHUDO DUH HYDOXDWHG 7KH IRUPHU LV HYDOXDWHG LQ DQ HPSOR\PHQW VHWWLQJ LQ WKUHH DUHDV Df 8QGHUVWDQGLQJ 6SHHFK ZLWK 9LVXDO &XHV Ef 5HVSRQVH WR $XGLWRU\ )DLOXUH DQG Ff 7KH ODWWHU LV PDGH XS RI JHQHUDO FRPPXQLFDWLRQ LWHPV WKDW GLG QRW ILW LQWR DQ\ RI WKH RWKHU FDWHJRULHV HJ +RZ RIWHQ FDQ \RX GR VRPHWKLQJ DERXW SRRU OLJKWLQJ WKDW LPSDLUV \RXU OLSUHDGLQJ DELOLW\" 2ZHQV t 5DJJLR S f 7KH UHVSRQGHQW LV LQVWUXFWHG WR DQVZHU HDFK

PAGE 63

TXHVWLRQ EDVHG RQ WKH W\SH DPSOLILFDWLRQ ZRUQ LI DQ\ IRU WKDW SDUWLFXODU VLWXDWLRQ )RU HDFK TXHVWLRQ WKHUH DUH VL[ SRVVLEOH UHVSRQVHV WKDW DUH DVVLJQHG D YDOXH LQ WKH IROORZLQJ PDQQHU 1HYHU $OPRVW 1HYHU 2FFDVLRQDOO\ $ERXW +DOI 7KH 7LPH )UHTXHQWO\ 3UDFWLFDOO\ $OZD\V $OZD\V ,I WKH SHUVRQ UHVSRQGV ZLWK 'RHV QRW DSSO\ WKH LWHP LV QRW VFRUHG $ PHDQ VFRUH LV REWDLQHG IRU HDFK FDWHJRU\ ZLWK WKH H[FHSWLRQ RI WKH *HQHUDO DQG 2FFXSDWLRQ FDWHJRULHV ZKLFK DUH LQWHUSUHWHG VHSDUDWHO\ ,Q IDFW WKH DXWKRUV VWDWH WKDW DOO LWHPV FDQ EH WUHDWHG VLQJO\ LQ D UHKDELOLWDWLYH SURJUDP 2ZHQV t 5DJJLR S f 2ZHQV DQG 5DJJLR f DOVR PDNH WKH IROORZLQJ UHFRPPHQGDWLRQV 5HJDUGLQJ WKH LQWHUSUHWDWLRQ RI DQ LQGLYLGXDO SURILOH WKH XVH RI SHUFHQWDJH VFRUHV LV QRW ZDUUDQWHG EHFDXVH RI WKH VPDOO QXPEHU RI LWHPV LQ HDFK VFDOH 3UHIHUDEO\ LQ GLVFXVVLQJ WKH UHVXOWV ZLWK D FOLHQW WKH PHDQ QXPHULFDO IRU WKH VFDOHV EH WUHDWHG DFFRUGLQJ WR WKH FRUUHVSRQGLQJ GHVFULSWLYH WHUPV DV IROORZV QHYHUf SUDFWLFDOO\ QHYHUf LRQDOO\f DERXW KDOI WKH IUHTXHQWO\f SUDFWLFDOO\ DOZD\Vf DQG DOZD\Vf WLPHf RFFDV S f $V FDQ EH VHHQ LQ )LJ WKH VXEMHFWV LQ WKLV VWXG\ H[KLELWHG D ZLGH UDQJH RI UHVSRQVHV WR WKH 3,36/ FDWHJRULHV

PAGE 64

869 ,17 5$) (6 8619 3(5 898QGHUVWDQGQJ 6SHHFK ZLWK YLVXDO &XHV ,1 7 QWHQVO W \ 5$)5HVSRQVH WR $XGLWRU\ )DLOXUH ((QYLURQPHQWDO 6RXQGV 8198QGHUVWDQGOQR 6SHHFK ZLWK 1R YLVXDO &XHV D 3 (5 3HUVRQDO )LJXUH 0HDQ VFRUHV IRU 3HUIRUPDQFH ,QYHQWRU\ IRU 3URIRXQG DQG 6HYHUH /RVV 3,36/fA

PAGE 65

DQG WKHUH ZDV ZLGH YDULDELOLW\ EHWZHHQ VXEMHFWV *URXS HDQV DQG UDQJHV DUH LOOXVWUDWHG LQ )LJ DQG IRXU RI WKH DUHDV GHVFULEH WKH JURXSn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f 7KHVH WDVNV ZHUH SHUIRUPHG LQ WKUHH GLIIHUHQW FRQGLWLRQV Df VSHHFK SURFHVVRU RII Ef VSHHFK SURFHVVRU RQ DQG Ff FRQYHQWLRQDO DPSOLILFDWLRQ LQ WKH XQLPSODQWHG 7R LQVXUH XQLIRUPLW\ VXEMHFWV ZHUH JLYHQ ZULWWHQ LQVWUXFWLRQV IRU WKH H[SHULPHQWDO WDVNV DQG DQ RSSRUWXQLW\ WR FODULI\ DQ\ TXHVWLRQV UHJDUGLQJ WKH WDVNV (TXLSPHQW (TXLSPHQW WR FRQGXFW WKH WHVW SURWRFRO IRU WKLV UHVHDUFK FRQVLVWHG RI WKH IROORZLQJ Df WKH VXEMHFWnV 1XFOHXV PXOWLFKDQQHO FRFKOHDU LPSODQW VSHHFK SURFHVVRU DQG FXVWRP SDWFK FRUG Ef 3KRQLF 0LUURU PLQL'$) 30 Ff 8QLWURQ 8( 33 / EHKLQGWKHHDU KHDULQJ DLG DQG DXGLR

PAGE 66

+LJK/RZ 0HDQ 898QGHU VWDQGLQJ 6SHHFK ZLWK YLVXDO &XHV ,17OQWHQVOW\ 5$)5HHSRQHH WR $XGLWRU\ )DLOXUH ((QYOURQPHQWDO 6RXQGV 861 98QGHU VWDQGL QJ 6SHHFK ZLWK 1R 9LVXDO &XHV 3(53HUVRQHO )LJXUH *URXS 0HDQ 6FRUHV DQG 5DQJHV IRU 3HUIRUPDQFH ,QYHQWRU\ IRU 3URIRXQG DQG 6HYHUH /RVV 3,36/f 8

PAGE 67

LQSXW ERRW Gf 8QLWURQ 'LUHFW $XGLR ,QSXW .LW DQG Hf $,:$ FDVVHWWH WDSH UHFRUGHU ZLWK RQHKDOI LQFK PLFURSKRQH 7KH IXQFWLRQLQJ RI WKH FRFKOHDU LPSODQW ZDV FKHFNHG XVLQJ WKH 1XFOHXV &KDQQHO &RFKOHDU ,PSODQW 6\VWHP 7KLV V\VWHP LV FRPSRVHG RI DQ ,%0 FRPSDWLEOH PLFURFRPSXWHU WKH GXDO SURFHVVRU LQWHUIDFH '3,f DQG FXVWRPL]HG VRIWZDUH 7KLV V\VWHP LV XVHG LQLWLDOO\ WR FUHDWH D PDSf RU SUHVFULSWLRQ IRU WKH LQGLYLGXDO VXEMHFW 7KH PDS LV FUHDWHG E\ DWWDFKLQJ WKH VSHHFK SURFHVVRU WR WKH '3, DQG SURJUDPPLQJ HDFK HOHFWURGH VHSDUDWHO\ 7KH SDUDPHWHUV IRU WKH PDS DUH WKH SDWLHQWVn WKUHVKROG WKH VRIWHVW OHYHO RI VRXQG WKH\ UHSRUWHG KHDULQJf DQG WKH PD[LPXP FRPIRUW OHYHO LH WKH ORXGHVW FRPIRUWDEOH OHYHO RI VRXQG (DFK VXEMHFWnV LPSODQW ZDV FKHFNHG SULRU WR WKHLU SDUWLFLSDWLQJ LQ WKH VWXG\ 7KLV ZDV DFFRPSOLVKHG E\ DWWDFKLQJ WKH VSHHFK SURFHVVRU WR WKH '3, DQG VZHHSLQJ WKH HOHFWURGHV DOORZLQJ D FRPSDULVRQ DQG FRQILUPDWLRQ RI WKH VSHHFK SURFHVVRU PDS DQG WKH ODVW PDS $FFRUGLQJ WR WKH PDQXIDFWXUHUnV SURGXFW LQIRUPDWLRQ VKHHW WKH 3KRQLF 0LUURU PLQL'$) KDV D GHOD\ FRQWURO RI DSSUR[LPDWHO\ PLOOLVHFRQGV PVf DW SRVLWLRQ QXPEHU WR D PD[LPXP GHOD\ RI PV DW SRVLWLRQ QXPEHU HIIHFW RI YDU\LQJ DXGLWRU\ IHHGEDFN GXUDWLRQ ZDV 7KH LQYHVWLJDWHG E\ %ODFN f +H UHSRUWHG WKDW D PLQLPDO GHOD\ RI HYHQ PV SURGXFHG VLJQLILFDQWO\ ORQJHU UHDGLQJ UDWHV LQ KLV VXEMHFWV 7R LQVXUH WKDW WKHUH ZDV QR

PAGE 68

SRVVLELOLW\ RI WKH PV GHOD\ SURGXFHG E\ WKH PLQL'$) XQLW GLDO VHOHFWRU FRQWUROf LQIOXHQFLQJ WKH VXEMHFWVn UHVSRQVHV DOO VXEMHFWV ZHUH WHVWHG LQ WKH 6$) FRQGLWLRQ ZLWKRXW WKHLU VSHHFK SURFHVVRU EHLQJ FRQQHFWHG WR WKH PLQL'$) 7KLV QHFHVVLWDWHG XVLQJ WZR VHSDUDWH PLFURSKRQHV 7KH UHFRUGLQJ PLFURSKRQH ZDV FRQQHFWHG WR WKH $,:$ FDVVHWWH WDSH UHFRUGHU WKURXJKRXW DOO RI WKH WHVW FRQGLWLRQV $Q DGGLWLRQDO PLFURSKRQH /DSHO 0LFURSKRQH $7 f SURYLGHG ZLWK WKH PLQL'$) ZDV DGGHG GXULQJ DOO WKH '$) WHVW ,W ZDV UHFRJQL]HG WKDW WKH QHFHVVLW\ RI XVLQJ WZR PLFURSKRQHVf§RQH IRU UHFRUGLQJ DQG RQH IRU URXWLQJ WKH VSHDNHUnV RXWSXW WKURXJK WKH '$)f§ZDV D OLPLWDWLRQ KRZHYHU LW FRXOG QRW EH RYHUFRPH ZLWK WKH DYDLODEOH HTXLSPHQW ,Q DGGLWLRQ WKHUH ZDV DQ LPSHGDQFH PLVPDWFK EHWZHHQ WKH FRFKOHDU LPSODQW VSHHFK SURFHVVRU DQG WKH PLQL'$) XQLW 7R RYHUFRPH WKLV D FXVWRP SDWFK FRUG ZDV SURYLGHG E\ 3KRQLF ,W VKRXOG DOVR EH QRWHG WKDW WKHUH ZDV QR IUHTXHQF\ VKDSLQJ RI WKH VLJQDO WDNLQJ SODFH DV WKDW VLJQDO ZDV URXWHG WKURXJK WKH '$) WKHUHIRUH WKH RQO\ FKDQJH RFFXUULQJ ZDV WKH SUHVHW GHOD\ 5 0HQGR]D SHUVRQDO FRPPXQLFDWLRQ f 7R FDOLEUDWH WKH PLQL'$) XQLW D VLJQDO ZDV JHQHUDWHG XVLQJ &RXOERXUQ LQVWUXPHQW PRGXOHV 7KLV VLJQDO KDG D GXUDWLRQ RI PLOOLVHFRQGV PVf ZLWK DQ LQVWDQWDQHRXV ULVHIDOO WLPH DQG D QRPLQDO IUHTXHQF\ RI +] 7KH RXWSXW ZDV GHOLYHUHG WR D VWDQGDUG DXGLRPHWULF HDUSKRQH DWWDFKHG WR WKH PLFURSKRQH RI WKH PLQL'$) DQG WKH

PAGE 69

RXWSXW ZDV IHG LQWR D 7HNWURQL[ 7\SH 7KH GHOD\ WLPH RI WKH PLQL'$) ZDV DGMXVWHG E\ YLVXDOO\ REVHUYLQJ WKH RXWSXW GLVSOD\HG RQ WKH RVFLOORVFRSH 2QFH D PV VLJQDO UDWH ZDV REWDLQHG WKH GHOD\ FRQWURO NQRE RQ WKH PLQL'$) ZDV VHFXUHG LQ D IL[HG SRVLWLRQ $W WKH HQG RI GDWD FROOHFWLRQ WKH GHOD\ WLPH PVf VLJQDO ZDV FRQILUPHG XVLQJ WKH HTXLSPHQW DQG PHWKRG GHVFULEHG DERYH 7HVWLQJ ZLWK FRQYHQWLRQDO DPSOLILFDWLRQ DQG '$) ZDV DFFRPSOLVKHG XVLQJ D 8QLWURQ 8( 33/ EHKLQGWKHHDU KHDULQJ DLG DQG GLUHFW DXGLR LQSXW 7KH XVH RI WKH ERRW HQDEOHG WKH H[SHULPHQWHU WR FRQQHFW WKH KHDULQJ DLG WR WKH PLQL'$) 7KH ERRW ZDV VHW WR H[FOXGH WKH KHDULQJ DLG PLFURSKRQH WKHUHE\ SUHYHQWLQJ DPSOLILFDWLRQ RI DQ\ HQYLURQPHQWDO VRXQGV 7KH UHVXOW RI WKLV DUUDQJHPHQW ZDV WKDW RQO\ WKH VXEMHFWnV VSHHFK ZDV WUDQVPLWWHG WKURXJK WKH KHDULQJ DLG DQG PLQL'$) XQLW 7KH VXEMHFWV ZRUH D VWRFN UHJXODU VW\OH HDUPROG GXULQJ WHVWLQJ 7KH H[FHSWLRQ WR WKLV ZDV RQH VXEMHFW ZKR VWLOO ZHDUV D KHDULQJ DLG LQ KLV XQLPSODQWHG HDU KLV RZQ UHJXODU VW\OH HDUPROG +H XVHG $Q HOHFWURDFRXVWLFDO DQDO\VLV RI WKH KHDULQJ DLG $16, f ZDV FRQGXFWHG DW WKH EHJLQQLQJ DQG WKH FRQFOXVLRQ RI WKH VWXG\ WR FRQILUP LWV SHUIRUPDQFH EDVHG RQ WKH DQXIDFWXUHUV VSHFLILFDWLRQ GDWD ,QLWLDOO\ FRXSOLQJ WKH KHDULQJ DLG WR WKH PLQL'$) UHVXOWHG LQ WKH RXWSXW RYHUGULYLQJ WKH KHDULQJ DLG 7R RYHUFRPH WKLV SUREOHP LW ZDV GHWHUPLQHG WKDW WR G% DWWHQWXDWLRQ ZDV QHHGHG -

PAGE 70

6HDPDQV SHUVRQDO FRPPXQLFDWLRQ f 7KLV ZDV DFKLHYHG XVLQJ WKH DWWHQWXDWRU SURYLGHG ZLWK WKH GLUHFW DXGLR LQSXW NLW 7KH DWWHQXDWRU RXWSXW ZDV PHDVXUHG HOHFWRDFRXVWLFDOO\ DQG WKH PD[LPXP DWWHQWXDWLRQ UHFRUGHG ZDV G% 63/ 7KH KHDULQJ DLG YROXPH FRQWURO ZDV VHW WR PLGOHYHO YROXPH VHWWLQJ f DQG ZDV FRXSOHG WR WKH DWWHQXDWRU 7KH DWWHQWXDWRU RXWSXW ZDV DJDLQ PHDVXUHG DV LWV RXWSXW FRQWURO NQRE ZDV URWDWHG DQG WKH NQRE ZDV VHFXUHG LQ D IL[HG SRVLWLRQ ZKHQ WKH DWWHQXDWLRQ SURYLGHG ZDV G% RI DWWHQXDWLRQ 6HDPDQV SHUVRQDO FRPPXQLFDWLRQ f &RQGLWLRQV 7KUHH H[SHULPHQWDO FRQGLWLRQV ZHUH HYDOXDWHG Df FRFKOHDU LPSODQW RII Ef FRFKOHDU LPSODQW RQ DQG Ff FRQYHQWLRQDO DPSOLILFDWLRQ LQ WKH XQLPSODQWHG HDU H[SHULPHQWDO WUHDWPHQWV ZHUH DGPLQLVWHUHG LQ HDFK 7ZR H[SHULPHQWDO FRQGLWLRQ Df VLPXOWDQHRXV DXGLWRU\ IHHGEDFN 6$)f DQG Ef GHOD\HG DXGLWRU\ IHHGEDFN '$)f 7KHVH WZR WUHDWPHQWV ZHUH DOWHUQDWHG LQ WKH IROORZLQJ PDQQHU 6$) ZLWK SURFHVVRU RIIRQ '$) ZLWK SURFHVVRU RIIRQ DQG 6$) ZLWK FRQYHQWLRQDO DPSOLILFDWLRQ DQG '$) ZLWK FRQYHQWLRQDO DPSOLILFDWLRQ 6$) DOZD\V SUHFHGHG '$) LQ HDFK FRQGLWLRQ DQG ZDV XVHG DV EDVHOLQH GDWD 0HWKRGV DQG 0DWHULDOV 7R GHWHUPLQH WKH RUGHU RI WKH SUHVHQWDWLRQ RI WKH H[SHULPHQWDO FRQGLWLRQV WKH VSHHFK SURFHVVRU RQ RU

PAGE 71

RIIff WKH RQ FRQGLWLRQ ZDV GHVLJQDWHG DQ RGG QXPEHU DQG WKH RIIf FRQGLWLRQ ZDV GHVLJQDWHG DQ HYHQ QXPEHU 8VLQJ D UDQGRP QXPEHUV WDEOH D QXPEHU ZDV VHOHFWHG IRU WKH ILUVW VXEMHFW ,I WKDW QXPEHU HQGHG LQ DQ RGG QXPEHU WKH RQ FRQGLWLRQ ZDV VHOHFWHG DV WKH ILUVW FRQGLWLRQ DQG WKH RII FRQGLWLRQ ZDV QXPEHU WZR ,I WKH QXPEHU VHOHFWHG ZDV DQ HYHQ QXPEHU WKH RII FRQGLWLRQ ZDV VHOHFWHG DV WKH ILUVW FRQGLWLRQ DQG LQ WKH VHFRQG FRQGLWLRQ WKH VSHHFK SURFHVVRU ZDV RQ )RU VXEVHTXHQW VXEMHFWV WKH FRQGLWLRQV ZHUH FRXQWHUEDODQFHG EDVHG RQ WKH ILUVW VXEMHFW +HJGH f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

PAGE 72

GLIILFXOW\ ZLWK WKLV W\SH RI WDVN WKDQ \RXQJHU SHRSOH ,QWHUSUHWDWLRQ RI FRXQWLQJ UHVXOWV LQ WKLV VWXG\ QHHG WR EH PDGH ZLWK WKHVH OLPLWDWLRQV LQ PLQG 3IHLIIHU f LQFOXGHG EDFNZDUG FRXQWLQJ LQ KLV 6KRUW 3RWDEOH 0HQWDO 6WDWXV 4XHVWLRQQDLUH 63062f WR WHVW IRU FRJQLWLYH IXQFWLRQLQJ LQ ROGHU DGXOWV VLQFH WKLV VNLOO PLJKW EH UHODWHG WR FRJQLWLYH GHFOLQH LQ WKH HOGHUO\ 'XULQJ '$) WHVWLQJ WKH VHOHFWHG YROXPH RQ WKH PLQL'$) ZDV EDVHG RQ WKH VXEMHFWnV UHSRUWHG FRPIRUW OHYHO 7KH LPSODQW VSHHFK SURFHVVRU ZDV FRQQHFWHG GLUHFWO\ WR WKH PLQL'$) XQLW LQ WKH SUHYLRXVO\ GHVFULEHG PDQQHU $ PRXWK WRPLFURSKRQH GLVWDQFH RI LQFKHV ZDV PDLQWDLQHG XVLQJ D KHDG KHOG PLFURSKRQH VHWXS DQG WKH ODSHO PLFURSKRQH $7 f SURYLGHG ZLWK WKH PLQL'$) XQLW 7KLV DOORZHG WKH VXEMHFWnV VSHHFK SURGXFWLRQV WR EH SDVVHG WKURXJK WKH PLQL'$) UHVXOWLQJ LQ WKHLU KHDULQJ LW ZLWK D PV GHOD\ )ROORZLQJ FRPSOHWLRQ RI WKH WHVW SURWRFRO ZLWK WKH FRFKOHDU LPSODQW WKH FRQGLWLRQV ZHUH UHSHDWHG ZLWK WKH VXEMHFW ZHDULQJ WKH 8QLWURQ 8( 33/ EHKLQGWKHHDU KHDULQJ DLG LQ WKHLU XQLPSODQWHG HDUV 7KH KHDULQJ DLG LQWHUQDO FRQWUROV ZHUH VHW WR SURYLGH WKH ZLGHVW UHVSRQVH DQG WKH YROXPH ZDV VHOHFWHG EDVHG RQ WKH VXEMHFWnV UHSRUWHG FRPIRUW OHYHO 7R GHWHUPLQH WHVWUHWHVW UHOLDELOLW\ DOO RI WKH VXEMHFWV ZHUH JLYHQ RQH H[WUD WHVW FRQGLWLRQ WKDW ZDV UDQGRPO\ VHOHFWHG DQG DVVLJQHG SULRU WR WKHLU SDUWLFLSDWLRQ LQ WKH VWXG\ 7KDW FRQGLWLRQ ZDV UHSHDWHG LQ LWV HQWLUHW\

PAGE 73

$OO RI WKH VXEMHFWVn UHVSRQVHV ZHUH UHFRUGHG RQ DQ $,:$ FDVVHWWH WDSH UHFRUGHU XVLQJ D RQHKDOI LQFK FOLS PLFURSKRQH $ PRXWKWRPLFURSKRQH GLVWDQFH IRU WKH UHFRUGLQJ PLFURSKRQH RI LQFKHV ZDV PDLQWDLQHG GXULQJ WKH WHVWLQJ $QDO\VLV RI 'DWD 7UDQVFULSWLRQ &RQVHQVXV WUDQVFULSWLRQ 6KULEHUJ .ZLDWNRZVNL t +RIIPDQQ f XVLQJ WKH ,QWHUQDWLRQDO 3KRQHWLF $OSKDEHW ,3$f ZDV SHUIRUPHG E\ D VSHHFKODQJXDJH SDWKRORJLVW DQG WKH H[SHULPHQWHU RQ DOO RI WKH VXEMHFWnV H[SHULPHQWDO VSHHFK SURGXFWLRQV $ VRXQGE\VRXQG DQDO\VLV RI WKH VHFRQG DQG IRXUWK VHQWHQFHV RI WKH *UDQGIDWKHU 3DVVDJH +H GUHVVHV KLPVHOI LQ DQ ROG EDFN IURFN FRDW XVXDOO\ VHYHUDO EXWWRQV PLVVLQJ $ ORQJ EHDUG FOLQJV WR KLV FKLQ JLYLQJ WKRVH ZKR REVHUYH KLP D SURQRXQFHG IHHOLQJ RI WKH XWPRVW UHVSHFWf DQG WKH IROORZLQJ DGGLWLRQDO ZRUGV IURP WKH SDVVDJH FUDFNHG XSRQ WKH VKRUW PRUH DQG PRGHUQ ZDV SHUIRUPHG RQ WKH VXEMHFWnV VSHHFK SURGXFWLRQV LQ WKH 6$) DQG '$) FRQGLWLRQV 7KLV VDPSOH ZDV VHOHFWHG EDVHG RQ WKH IUHTXHQF\ RI RFFXUUHQFH RI WKH SKRQHPHV LQFOXGHG LQ FRQYHUVDWLRQDO (QJOLVK 0LQHV +DQVRQ t 6KRXS f 7KH SKRQRORJLFDO DQDO\VLV ZDV SHUIRUPHG E\ WKH 3URJUDPV WR ([DPLQH 3KRQHWLF DQG 3KRQRORJLF (YDOXDWLRQ 5HFRUGV 3(33(5f 9HUVLRQ 6KULEHUJ f 3(33(5 LV D JURXS RI FRPSXWHU SURJUDPV GHVLJQHG WR DQDO\]H VSHHFK GDWD ,W DOORZV WKH LQYHVWLJDWRU

PAGE 74

WR LQSXW SKRQHWLFDOO\ WUDQVFULEHG VSHHFK VDPSOHV DQG DQDO\]H WKHP IRU W\SH DQG IUHTXHQF\ RI VSHHFK VRXQG HUURU 7KH VXEMHFWn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f ,QWHUWUDQVFULEHU UHOLDELOLW\ ZDV GHWHUPLQHG IRU b RI WKH VDPSOHV 7KHVH ZHUH VHOHFWHG E\ DVVLJQLQJ HDFK WDSHG WHVW FRQGLWLRQ D QXPEHU EHWZHHQ DQG DQG WKHQ GUDZLQJ b RI WKHP RXW RI D ER[ 7KHVH VDPSOHV ZHUH LQGHSHQGHQWO\ WUDQVFULEHG E\ DQRWKHU VSHHFKODQJXDJH SDWKRORJLVW 7ZR FRPPRQO\ XVHG WHFKQLTXHV IRU FDOFXODWLQJ LQWHUREVHUYHU UHOLDELOLW\ KDYH EHHQ GLVFXVVHG E\ 0F5H\QROGV DQG .HDUQV f 7KH WRWDO PHWKRG LV EDVHG RQ SHUFHQWDJH DJUHHPHQW IRU WKH WRWDO QXPEHU RI REVHUYDWLRQV LQ D VWXG\ 3RLQWWRSRLQW UHOLDELOLW\ WDOOLHV REVHUYHU DJUHHPHQW EDVHG RQ WKH RFFXUUHQFH DQG QRQRFFXUUHQFH RI WKH WDUJHW EHKDYLRU 7KHVH DXWKRUV VWDWH WKDW WKH ILUVW WHFKQLTXH LV LQDSSURSULDWH EHFDXVH DOWKRXJK WZR REVHUYHUV

PAGE 75

D\ DJUHH RQ WKH WRWDO QXPEHU RI UHVSRQVHV REWDLQHG DJUHHPHQW UHJDUGLQJ WKH RFFXUUHQFH RI WKH WDUJHW EHKDYLRU LV ODFNLQJ ZHDNQHVV PHWKRG LL UHODWHV WR WKH IDFW WKDW WKH DJUHHPHQW OHYHO REWDLQHG LV D GLUHFW UHIOHFWLRQ RI WKH UDWH RI SURGXFWLRQ RI WKH WDUJHW EHKDYLRU 0F5H\QROGV t .HDUQV S f 7KH UHVXOW LV WKDW LQ LQVWDQFHV RI H[WUHPHO\ KLJK RU ORZ UDWHV RI REVHUYHG EHKDYLRUV WKHUH LV D KLJK SUREDELOLW\ WKDW DJUHHPHQW ZLOO EH REWDLQHG EDVHG RQ FKDQFH DORQH 0F5H\QROGV t .HDUQV S f ,Q DQ HIIRUW WR DYRLG WKH SLWIDOOV PHQWLRQHG DERYH D ; FKLVTXDUH DQDO\VLV IRU LQGHSHQGHQW VDPSOHV ZDV SHUIRUPHG WR GHWHUPLQH UHOLDELOLW\ EHWZHHQ WKH WUDQVFULEHUV +XFN &RUPLHU t %RXQGV f 7KH REWDLQHG ; GI ZDV VLJQLILFDQW EH\RQG WKH OHYHO RI FRQILGHQFH 6WDWLVWLFDO $QDO\VLV 7KH VPDOO VDPSOH 1 f LQ WKLV VWXG\ SURKLELWHG WKH XVH RI SDUDPHWULF VWDWLVWLFV WKHUHIRUH D )ULHGPDQ WZRZD\ DQDO\VLV RI YDULDQFH $129$f ZDV SHUIRUPHG ,Q DGGLWLRQ HIIHFW VL]H (6f ZDV FDOFXODWHG IRU GXUDWLRQ FRQVRQDQW HUURUV DQG YRZHO HUURUV IRU UHDGLQJ DQG FRXQWLQJ DV ZHOO DV IRU WKH FRFKOHDU LPSODQW DQG KHDULQJ DLG FRQGLWLRQV 1XOO K\SRWKHVHV H[SUHVV WKH QRWLRQ WKDW D SDUWLFXODU SKHQRPHQRQ EHLQJ VWXGLHG LV LQ IDFW QRW SUHVHQW &RKHQ f ZURWH WKDW WKH XVH RI HIIHFW VL]H WR GHVFULEH GDWD LV QRW LQWHQGHG WR VXJJHVW D FDXVH DQG HIIHFW UHODWLRQVKLS EXW UDWKHU LW LV

PAGE 76

FRQYHQLHQW WR XVH WKH SKUDVH nHIIHFW VL]Hn WR PHDQ nWKH GHJUHH WR ZKLFK WKH SKHQRPHQRQ LV SUHVHQW LQ WKH SRSXODWLRQn RU nWKH GHJUHH WR ZKLFK WKH QXOO K\SRWKHVLV LV IDOVHn S f 5HJDUGOHVV RI WKH W\SH RI SKHQRPHQRQ EHLQJ VWXGLHG WKH QXOO K\SRWKHVLV DOZD\V PHDQV WKDW WKH HIIHFW VL]H LV ]HUR DQG WKH ODUJHU WKLV YDOXH WKH JUHDWHU WKH GHJUHH WR ZKLFK WKH SKHQRPHQRQ XQGHU VWXG\ LV PDQLIHVWHG &RKHQ S f 7KLV UHODWLRQVKLS DOVR FDUULHV RYHU WR VDPSOH VL]H ZKHUH WKH ODUJHU WKH (6 SRVLWHG RWKHU WKLQJV VLJQLILFDQFH FULWHULRQ GHVLUHG SRZHUf EHLQJ HTXDO WKH VPDOOHU WKH VDPSOH VL]H QHFHVVDU\ WR GHWHFW LW &RKHQ S f (IIHFW VL]H FDQ EH GHVFULEHG LQ UHODWLYH WHUPV RI VPDOO PHGLXP DQG ODUJH LW 7R GHVFULEH WKHVH WHUPV IXUWKHU QXPHULFDO YDOXHV KDYH EHHQ GHILQHG Df D VPDOO HIIHFW VL]H LV Ef PHGLXP HIIHFW VL]H LV DQG Ff ODUJH VL]H ,Q VXPPDU\ WKH UHVHDUFK H[SHULPHQW ZDV D IDFWRULDO GHVLJQ ZLWK LQGHSHQGHQW YDULDEOHV Df 6$) Ef '$) Ff FRQYHQWLRQDO DPSOLILFDWLRQ Gf VSHHFK SURFHVVRU RII DQG Hf VSHHFK SURFHVVRU RQ 7KH GHSHQGHQW YDULDEOHV ZHUH UHDGLQJ UDWH Ef FRXQWLQJ UDWH DQG Ff RFFXUUHQFH RI Df 7KH H[SHULPHQWDO GHVLJQ FDQ EH GHVFULEHG DV WKH VXEMHFWnV VSHHFK SURFHVVRU LQ WZR FRQGLWLRQV RII RQf E\ WZR H[SHULPHQWDO WUHDWPHQWV 6$) '$)f $ WKLUG FRQGLWLRQ ZDV FRQYHQWLRQDO DPSOLILFDWLRQ E\ WZR H[SHULPHQWDO WUHDWPHQWV 6$) '$)f 'XH WR WKH VPDOO VDPSOH VL]H 1

PAGE 77

f DQG WKH UHSHDWHG PHDVXUHV WDNHQ RQ HDFK VXEMHFW WKH GDWD ZHUH VXEMHFWHG WR D )ULHGPDQ WZRZD\ DQDO\VLV RI YDULDQFH 0DUDVFXLOR t 0F6ZHHQH\ +XFN HW DO f DQG WR FDOFXODWLRQV RI HIIHFW VL]H &RKHQ f )LQDOO\ WHVWUHWHVW UHOLDELOLW\ RI WKH H[SHULPHQWDO FRQGLWLRQV ZDV HYDOXDWHG XVLQJ WKH 3HDUVRQ 3URGXFW0RPHQW VWDWLVWLF

PAGE 78

&+$37(5 ,9 5(68/76 7KH SXUSRVH RI WKLV VWXG\ ZDV WR LQYHVWLJDWH WKH HIIHFW RI GHOD\HG DXGLWRU\ IHHGEDFN '$)f RQ WKH VSHHFK SURGXFWLRQ RI SRVWOLQJXDO FRFKOHDU LPSODQW XVHUV ,Q DGGLWLRQ WKH VXEMHFWV ZHUH DOVR WHVWHG ZHDULQJ FRQYHQWLRQDO DPSOLILFDWLRQ LQ WKHLU XQLPSODQWHG HDU 7KH VSHFLILF UHVHDUFK TXHVWLRQV IRUPXODWHG LQ WKLV VWXG\ ZHUH ,V WKHUH D GLIIHUHQFH EHWZHHQ WKH 6LPXOWDQHRXV $XGLWRU\ )HHGEDFN 6$)f DQG 'HOD\HG $XGLWRU\ )HHGEDFN '$)f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

PAGE 79

YRZHO HUURUV E\ FRFKOHDU LPSODQW XVHUV ZKHQ ZHDULQJ D KHDULQJ DLG DORQH DQG SHUIRUPLQJ UHDGLQJ DQG FRXQWLQJ WDVNV" '$) (IIHFW RQ 5HDGLQJ DQG &RXQWLQJ 'XUDWLRQ 0HDQV DQG 5DQJHV 5HDGLQJ DQG FRXQWLQJ GXUDWLRQ PHDQV DQG UDQJHV LQ VHFRQGVf DV D IXQFWLRQ RI DPSOLILFDWLRQ W\SH DQG IHHGEDFN FRQGLWLRQ DUH UHSRUWHG LQ 7DEOH DQG LOOXVWUDWHG LQ )LJXUH DQG )LJXUH ([DPLQDWLRQ RI UHDGLQJ GXUDWLRQ PHDQV DQG UDQJHV UHYHDOHG QR GLIIHUHQFHV EHWZHHQ 6$) DQG '$) LQ WKH DEVHQFH RI DPSOLILFDWLRQ 6$) 0 V '$) 0 Vf +RZHYHU WKHUH ZHUH GXUDWLRQ GLIIHUHQFHV EHWZHHQ WKH 6$) DQG '$) PHDQV ZKHQ VXEMHFWV ZHUH WHVWHG ZLWK WKH FRFKOHDU LPSODQW 6$) 0 V '$) 0 Vf DQG WKH KHDULQJ DLG 6$) 0 V '$) 0 Vf :LGH UDQJHV LQ UHDGLQJ GXUDWLRQ ZHUH DOVR QRWHG ZKHQ VXEMHFWV ZRUH HLWKHU WKH FRFKOHDU LPSODQW Vf RU WKH KHDULQJ DLG Vf &RXQWLQJ GXUDWLRQ PHDQV UHPDLQHG VLPLODU XQGHU 6$)'$) LQ WKH DEVHQFH RI DPSOLILFDWLRQ 6$) 0 '$) 0 f ZLWK WKH FRFKOHDU LPSODQW 6$) 0 '$) 0 f DQG ZLWK WKH KHDULQJ DLG 6$) 0 '$) 0 f +RZHYHU FRXQWLQJ GXUDWLRQ YDULHG DPRQJ WKH VXEMHFWV IRU WKLV H[SHULPHQWDO WDVN

PAGE 80

7DEOH 'XUDWLRQ PHDQV DQG UDQJHV LQ VHFRQGVf LQ WKUHH FRQGLWLRQV QR DPSOLILFDWLRQFRFKOHDU LPSODQW KHDULQJ DLGf XQGHU VLPXODWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f ZKHQ UHDGLQJ *UDQGIDWKHU 3DVVDJH DQG FRXQWLQJ EDFNZDUGV 6$) '$) $PSOLILFDWLRQ ; 5DQJHV 7LPH6HFRQGV ; 7LO 5DQJHV QH6HFRQGV 5HDGLQJ 1RQH r&, rr+$ &RXQWLQJ 1RQH r&, rr+$ r&, &RFKOHDU ,PSODQW rr+$ +HDULQJ $LG

PAGE 81

ZR]RRPZ )LJXUH 1RQH &O +$ 1RQH &O +$ +LJK/RZ 0HDQ 5HDGLQJ GXUDWLRQ PHDQV DQG UDQJHV LQ WKUHH FRQGLWLRQV QR DPSOLILFDWLRQ 1RQHf &RFKOHDU ,PSODQW &Of DQG KHDULQJ DLG +$f XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f

PAGE 82

&'/822=4& 6$) '$) +LJK/RZ WW 0HDQ )LJXUH &RXQWLQJ GXUDWLRQ PHDQV DQG UDQJHV LQ WKUHH FRQGLWLRQV QR DPSOLILFDWLRQ 1RQHf FRFKOHDU LPSODQW &Of DQG KHDULQJ DLG +$f XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f

PAGE 83

$129$ $ )ULHGPDQ WZRZD\ DQDO\VLV RI YDULDQFH $129$f ZDV SHUIRUPHG WR DQVZHU HDFK RI WKH UHVHDUFK TXHVWLRQV 7KLV VWDWLVWLFDO PHWKRG DVVLJQV UDQNV WR HDFK RI WKH PHDQ VFRUHV LQ D JURXS RI GDWD \LHOGLQJ D PHDQ UDQN VFRUH IRU HDFK FRQGLWLRQ 7KH JUHDWHU WKH GLIIHUHQFHV EHWZHHQ WKH PHDQ UDQN VFRUHV WKH JUHDWHU WKH GLIIHUHQFH EHWZHHQ WKH WHVW 'XUDWLRQ 7KHUH ZHUH QR VLJQLILFDQW GLIIHUHQFHV LQ HLWKHU WKH GXUDWLRQ RI UHDGLQJf§; 1 f S f§RU WKH GXUDWLRQ RI FRXQWLQJf§; 1 f S f§ LQ WKH 6$) DQG '$) FRQGLWLRQV UHJDUGOHVV RI WKH DEVHQFH RU SUHVHQFH RI DPSOLILFDWLRQ 7KH PHDQ UDQN VFRUHV IRU UHDGLQJ DQG FRXQWLQJ GXUDWLRQ DUH VXPPDUL]HG LQ 7DEOH DQG )LJXUH DQG 7DEOH DQG )LJXUH UHVSHFWLYHO\ ([DPLQDWLRQ RI UHDGLQJ PHDQ UDQN VFRUHV LQ 7DEOH UHYHDOHG WKDW LQ WKH DEVHQFH RI DPSOLILFDWLRQ WKH VXEMHFWVn VFRUHV ZHUH ODUJHU f LQ WKH 6$) FRQGLWLRQ WKDQ LQ WKH '$) FRQGLWLRQ f LQGLFDWLQJ WKDW WKHLU UHDGLQJ GXUDWLRQ ZDV ORQJHU XQGHU 6$) 2SSRVLWH UHVXOWV ZHUH REWDLQHG ZLWK WKH FRFKOHDU LPSODQW DQG WKH KHDULQJ DLG 0HDQ UDQN VFRUHV ZKHQ WKH FRFKOHDU LPSODQW ZDV ZRUQ ZHUH 6$)f DQG '$)f DQG ZLWK WKH KHDULQJ DLG 6$)f DQG '$)f VXJJHVWLQJ WKDW WKH VXEMHFWV WRRN ORQJHU WR UHDG WKH SDVVDJH ZKHQ H[SHULHQFLQJ '$) ZLWK HLWKHU W\SH RI DPSOLILFDWLRQ 7R

PAGE 84

7DEOH 0HDQ UDQN VFRUHV DQG HIIHFW VL]H YDOXHV LQ WKUHH UHDGLQJ FRQGLWLRQV QR DPSOLILFDWLRQ FRFKOHDU LPSODQW KHDULQJ DLGf XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f $f 'XUDWLRQ 5HDGLQJ $PSOLILFDWLRQ 1RQH 'HYLFH &Or +$rr 6$) '$) (6rrr %f &RQVRQDQW (UURUV f $PSOLILFDWLRQ 'HYLFH 6$) f '$) (6 &f 9RZHO (UURUV $PSOLILFDWLRQ 'HYLFH 6$) '$) (6 r&, rr+$ rrr(6 &RFKOHDU ,PSODQW +HDULQJ $LG (IIHFW 6L]H

PAGE 85

)LJXUH 0HDQ UDQN VFRUHV IRU UHDGLQJ GXUDWLRQ

PAGE 86

7DEOH 0HDQ UDQN VFRUHV DQG HIIHFW VL]H YDOXHV LQ WKUHH FRXQWLQJ FRQGLWLRQV QR DPSOLILFDWLRQ FRFKOHDU LPSODQW KHDULQJ DLGf XQGHU VLPXOWDQHRXV DQG GHOD\HG IHHGEDFN 6$)'$)f &RXQWLQJ $f 'XUDWLRQ f $PSOLILFDWLRQ 1RQH 'HYLFH &Or +$rr 6$) '$) (6rrr %f &RQVRQDQW (UURUV $PSOLILFDWLRQ 'HYLFH 6$) '$) (6 &f 9RZHO (UURUV $PSOLILFDWLRQ 'HYLFH 6$) '$) (6 r&, &RFKOHDU ,PSODQW rr+$ +HDULQJ $LG rrr(6 (IIHFW 6L]H

PAGE 87

VFRUHV IRU FRXQWLQJ GXUDWLRQ )LJXUH 0HDQ UDQN

PAGE 88

IXUWKHU HYDOXDWH WKHVH GDWD FDOFXODWLRQV RI HIIHFW VL]H (6f ZHUH SHUIRUPHG &RKHQ f $V ZDV VWDWHG LQ &KDSWHU HIIHFW VL]H LV QRW LQWHQGHG WR LPSO\ D FDXVH DQG HIIHFW UHODWLRQVKLS EXW UDWKHU WKH GHJUHH WR ZKLFK D UHODWLRQVKLS EHWZHHQ WZR PHDVXUHV PD\ H[LVW &RKHQ f $ ODUJH HIIHFW VL]H ZRXOG VXJJHVW WKDW GLIIHUHQFHV GLG H[LVW EHWZHHQ WZR FRQGLWLRQV HJ 6$) DQG '$) (IIHFW VL]H YDOXHV IRU UHDGLQJ GXUDWLRQ DUH VXPPDUL]HG LQ 7DEOH $ VPDOO (6 YDOXH f ZDV VHHQ ZLWKRXW DPSOLILFDWLRQ DQG YHU\ ODUJH YDOXHV ZHUH VHHQ IRU ERWK WKH FRFKOHDU LPSODQW f DQG KHDULQJ DLG f FRQGLWLRQV &RXQWLQJ 7KH FRXQWLQJ GXUDWLRQ PHDQ UDQN VFRUHV DUH VXPPDUL]HG LQ 7DEOH DQG LOOXVWUDWHG LQ )LJXUH 7KHVH UHVXOWV LQGLFDWH WKDW WKH VXEMHFWV WRRN ORQJHU WR SHUIRUP WKH FRXQWLQJ WDVN XQGHU '$) f WKDQ XQGHU 6$) f 7KH VDPH SDWWHUQ ZDV REVHUYHG ZKHQ WKH FRFKOHDU LPSODQW ZDV ZRUQ '$)f DQG 6$)f 7KLV SDWWHUQ FRQWLQXHG ZKHQ WKH VXEMHFWV ZRUH WKH KHDULQJ DLG XQGHU '$) f DQG XQGHU 6$) f $V FDQ EH VHHQ LQ 7DEOH WKH FRXQWLQJ GXUDWLRQ WDVNV UHVXOWV \LHOGHG WKH VDPH SDWWHUQ IRU (6 YDOXHV LQ WKH DEVHQFH RI DPSOLILFDWLRQ LH D VPDOO (6 YDOXH f WKDW ZDV QRWHG LQ WKH UHDGLQJ GDWD 8QOLNH WKH UHDGLQJ GDWD WKLV ILQGLQJ RI VPDOO HIIHFW VL]H DOVR KHOG WUXH IRU WKH FRFKOHDU LPSODQW f DQG KHDULQJ DLG f FRQGLWLRQV

PAGE 89

'$) (IIHFW RQ 1XPEHU RI &RQVRQDQW DQG 9RZHO 0HDQV DQG 5DQJHV 0HDQV DQG UDQJHV IRU FRQVRQDQW DQG YRZHO HUURUV GXULQJ UHDGLQJ DQG FRXQWLQJ DUH SUHVHQWHG LQ 7DEOH DQG 7DEOH DQG LOOXVWUDWHG LQ WKURXJK $OO QRQVWDQGDUG RPLVVLRQV VXEVWLWXWLRQV DQG GHOHWLRQV RI FRQVRQDQWV DQG YRZHOV ZHUH FRXQWHG DV HUURUV 6XJJHVWLRQV IURP WKH 3(33(5 PDQXDO f ZHUH XVHG WR GHWHUPLQH LI YDULDWLRQV LQ SURGXFWLRQV ZHUH VWDQGDUG FDVXDO VSHHFK RU HUURUV 5HDGLQJ ([DPLQDWLRQ RI 7DEOH UHYHDOHG VPDOO GLIIHUHQFHV LQ WKH QXPEHU RI UHDGLQJ FRQVRQDQW HUURUV LQ WKH DEVHQFH RI DPSOLILFDWLRQ 6$) 0 '$) 0 f DQG ZLWK WKH KHDULQJ DLG 6$) 0 '$) 0 f 7KHUH ZHUH ODUJH GLIIHUHQFHV LQ WKH UDQJH RI VFRUHV KRZHYHU LQGLFDWLQJ ZLGH YDULDELOLW\ DPRQJ WKH VXEMHFWV XQGHU 6$) DQG '$) 9RZHO UHDGLQJ HUURUV IROORZHG WKH VDPH SDWWHUQ LH VPDOO GLIIHUHQFHV EHWZHHQ WKH 6$)'$) FRQGLWLRQ 7KH PHDQV ZHUH 6$)f DQG '$)f LQ WKH DEVHQFH RI DPSOLILFDn WLRQ 6$)f DQG '$)f ZLWK WKH FRFKOHDU LPSODQW DQG 6$)f DQG '$)f ZLWK WKH KHDULQJ DLG 7KH UDQJHV ZHUH VPDOOHU IRU YRZHO HUURUV ZLWK WKH H[FHSWLRQ RI WKH QR DPSOLILFDWLRQ FRQGLWLRQ 6$) '$) f &RXQWLQJ 0HDQV IRU FRQVRQDQW FRXQWLQJ HUURUV \LHOGHG VPDOO GLIIHUHQFHV EHWZHHQ 6$)'$) ZLWKRXW DPSOLILFDWLRQ 6$) 0 '$) 0 f ZLWK WKH FRFKOHDU LPSODQW 6$) 0

PAGE 90

7DEOH 0HDQ DQG UDQJHV IRU FRQVRQDQW DQG YRZHO HUURUV LQ WKUHH FRQGLWLRQV QR DPSOLILFDWLRQ FRFKOHDU LPSODQW KHDULQJ DLGf XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f ZKHQ UHDGLQJ *UDQGIDWKHU 3DVVDJH &RQVRQDQW (UURUV 6$) '$) $PSOLILFDWLRQ ; 5DQJHV (UURUV ; 5DQJHV (UURUV 1RQH r&, rr+$ 9RZHO (UURUV 6$) '$) $PSOLILFDWLRQ ; 5DQJHV (UURUV ; 5DQJHV (UURUV 1RQH r&, rr+$ r&, &RFKOHDU ,PSODQW rr+$ +HDULQJ $LG

PAGE 91

7DEOH 0HDQV DQG UDQJHV IRU FRQVRQDQW DQG YRZHO HUURUV LQ WKUHH FRQGLWLRQV QR DPSOLILFDWLRQ FRFKOHDU LPSODQW KHDULQJ DLGf XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f ZKHQ FRXQWLQJ EDFNZDUGV $PSOLILFDWLRQ &RQVRQDQW (UURUV 6$) ; 5DQJHV (UURUV '$) ; 5DQJHV (UURUV 1RQH r&, rr+$ 9RZHO (UURUV 6$) '$) ; 5DQJHV ; 5DQJHV $PSOLILFDWLRQ (UURUV f (UURUV 1RQH r&, rr+$ r&, &RFKOHDU ,PSODQW rr+$ +HDULQJ $LG

PAGE 92

A(FGXM 2OA /XFFFU2FQFR 1RQH &O +$ 1RQH &O +$ +LJK/RZ t 0HDQ )LJXUH 0HDQV DQG UDQJHV RI FRQVRQDQW HUURUV IRU UHDGLQJ LQ WKUHH FRQGLWLRQV QR DPSOLILFDWLRQ 1RQHf FRFKOHDU LPSODQW &Of DQG KHDULQJ DLG XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f +$f

PAGE 93

] ]! P OX FU 2OA /XFFFU2DLFR 6$3 '$) +LJK/RZ 70HDQ )LJXUH 0HDQV DQG UDQJHV RI YRZHO HUURUV IRU UHDGLQJ LQ WKUHH FRQGLWLRQV QR DPSOLILFDWLRQ 1RQHf FRFKOHDU LPSODQW &Of DQG KHDULQJ DLG +$f XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f

PAGE 94

&4/8&& 2OA OXFFFF2FFFR 6$) '$) +LJK/RZ 0HDQ )LJXUH 0HDQV DQG UDQJHV RI FRQVRQDQW HUURUV IRU FRXQWLQJ LQ WKUHH FRQGLWLRQV QR DPSOLILFDWLRQ 1RQHf FRFKOHDU LPSODQW &Of DQG KHDULQJ DLG +$f XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f

PAGE 95

1 8 0 % ( 5 2 ) ( 5 5 2 5 6 6$) '$) )OLJK/RZ 0HDQ )LJXUH 0HDQV DQG UDQJHV RI YRZHO HUURUV IRU FRXQWLQJ LQ WKUHH FRQGLWLRQV QR DPSOLILFDWLRQ 1RQHf FRFKOHDU LPSODQW &Of DQG KHDULQJ DLG +$f XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f RR -

PAGE 96

'$) 0 f DQG ZLWK WKH KHDULQJ DLG 6$) 0 '$) 0 f +RZHYHU WKH UDQJHV IRU FRQVRQDQW FRXQWLQJ HUURUV ZHUH YHU\ ODUJH LQ WKH 6$) DQG '$) FRQGLWLRQ 0HDQV IRU YRZHO FRXQWLQJ HUURUV DOVR \LHOGHG VPDOO GLIIHUHQFHV EHWZHHQ 6$)'$) ZLWKRXW DPSOLILFDWLRQ 6$) 0 '$) 0 f ZLWK WKH FRFKOHDU LPSODQW 6$) 0 '$) 0 f DQG ZLWK WKH KHDULQJ DLG 6$) 0 '$) 0 f 7KH SDWWHUQ RI D ZLGH UDQJH RI VFRUHV DPRQJ WKH VXEMHFWV VHHQ LQ WKH SUHYLRXV H[SHULPHQWDO FRQGLWLRQV FRQWLQXHG IRU YRZHO FRXQWLQJ HUURUV $129$ 5HDGLQJ 7KH UHVXOWV RI WKH )ULHGPDQ WZRZD\ $129$ ZHUH ; 1 f S DQG ; 1 f J IRU UHDGLQJ FRQVRQDQW DQG YRZHO HUURUV 7KHVH ILQGLQJV UHYHDOHG WKDW WKH LQWURGXFWLRQ RI '$) GLG QRW UHVXOW LQ D VLJQLILFDQW GLIIHUHQFH LQ WKH QXPEHU RI FRQVRQDQW RU YRZHO HUURUV IRU UHDGLQJ 0HDQ UDQN VFRUHV IRU UHDGLQJ FRQVRQDQW HUURUV DUH VXPPDUL]HG LQ 7DEOH DQG )LJXUH 7KH\ LQGLFDWH D JUHDWHU QXPEHU RI HUURUV XQGHU 6$) f YHUVXV '$) f LQ WKH DEVHQFH RI DPSOLILFDWLRQ 7KLV SDWWHUQ ZDV UHSHDWHG ZKHQ WKH VXEMHFWV ZRUH WKH KHDULQJ DLG XQGHU 6$) f DQG XQGHU '$) f +RZHYHU WKH SDWWHUQ ZDV UHYHUVHG ZKHQ WKH VXEMHFWV ZRUH WKH FRFKOHDU LPSODQW ,Q WKDW FRQGLWLRQ

PAGE 97

1RQH )LJXUH 0HDQ UDQN VFRUHV RI FRQVRQDQW HUURUV IRU UHDGLQJ

PAGE 98

PRUH FRQVRQDQW HUURUV ZHUH SURGXFHG XQGHU '$) f WKDQ XQGHU 6$) f ([DPLQDWLRQ RI HIIHFW VL]H IRU UHDGLQJ FRQVRQDQW HUURUV UHYHDOHG VPDOO (6 YDOXHV f LQ WKH DEVHQFH RI DPSOLILFDn WLRQ DQG ZLWK WKH KHDULQJ DLG f $ PRGHUDWH (6 YDOXH f ZDV QRWHG ZLWK WKH FRFKOHDU LPSODQW 0HDQ UDQN VFRUHV RI YRZHO UHDGLQJ HUURUV DUH VXPPDUL]HG LQ 7DEOH DQG )LJXUH 7KH '$) FRQGLWLRQ \LHOGHG ODUJHU PHDQ UDQN VFRUHV IRU UHDGLQJ YRZHO HUURUV LQ WKH DEVHQFH RI DPSOLILFDWLRQ f WKDQ LQ WKH 6$) FRQGLWLRQ f ZDV DOVR WKH FDVH ZKHQ WKH VXEMHFWV ZRUH WKH FRFKOHDU 7KLV LPSODQW XQGHU '$) f YHUVXV XQGHU 6$) f +RZHYHU UHDGLQJ YRZHO HUURUV ZHUH VPDOOHU ZLWK WKH KHDULQJ DLG XQGHU '$) f WKDQ 6$) f 6PDOO HIIHFW VL]H YDOXHV IRU UHDGLQJ YRZHO HUURUV ZHUH REWDLQHG ZLWKRXW DPSOLILFDWLRQ f DQG ZLWK WKH KHDULQJ DLG f $ PRGHUDWH (6 YDOXH ZDV REWDLQHG ZLWK WKH FRFKOHDU LPSODQW &RXQWLQJ 6WDWLVWLFDO DQDO\VLV RI FRXQWLQJ HUURUV UHYHDOHG ; 1 f S IRU FRQVRQDQW HUURUV DQG ; 1 f S IRU YRZHO HUURUV 7KLV ODFN RI VLJQLILFDQW GLIIHUHQFHV EHWZHHQ WKH 6$) DQG '$) FRQGLWLRQV LQ WKH FRXQWLQJ WDVN IROORZHG WKH VDPH SDWWHUQ DV VKRZQ LQ WKH UHDGLQJ WDVN 0HDQ UDQN VFRUHV IRU FRXQWLQJ FRQVRQDQW HUURUV VXPPDUL]HG LQ 7DEOH DQG LOOXVWUDWHG LQ )LJXUH VXJJHVWHG WKDW LQ WKH DEVHQFH RI DPSOLILFDWLRQ WKHUH ZDV QR

PAGE 99

)LJXUH 0HDQ UDQN VFRUHV RI YRZHO HUURUV IRU UHDGLQJ

PAGE 100

1RQH )LJXUH 0HDQ UDQN VFRUHV RI FRQVRQDQW HUURUV IRU FRXQWLQJ

PAGE 101

GLIIHUHQFH EHWZHHQ WKH QXPEHU RI HUURUV SURGXFHG XQGHU 6$) f DQG XQGHU '$) f 7KH VDPH SDWWHUQ ZDV VXJJHVWHG E\ WKH KHDULQJ DLG GDWD ZLWK WKH PHDQ UDQN VFRUHV EHLQJ 6$)f DQG '$)f (IIHFW VL]H YDOXHV IRU ERWK WKH DEVHQFH RI DPSOLILFDWLRQ f DQG WKH KHDULQJ DLG FRQGLWLRQ f ZHUH YHU\ VPDOO EXW ZHUH PRGHUDWH f IRU WKH FRFKOHDU LPSODQW 0HDQ UDQN VFRUHV IRU YRZHO FRXQWLQJ HUURUV DUH VXPPDUL]HG LQ 7DEOH DQG LOOXVWUDWHG LQ )LJXUH VFRUHV LQGLFDWHG WKDW WKH VPDOOHVW GLIIHUHQFHV EHWZHHQ 6$) f DQG '$) f ZHUH REWDLQHG ZLWK WKH KHDULQJ DLG 7KLV ZDV DOVR VXSSRUWHG E\ WKH YHU\ VPDOO (6 YDOXH f :LWKRXW DPSOLILFDWLRQ WKH PHDQ UDQN VFRUHV IRU YRZHO FRXQWLQJ HUURUV ZHUH 6$)f DQG '$)f ZLWK D VPDOO (6 YDOXH f 7KH ODUJHVW QXPEHU RI YRZHO FRXQWLQJ HUURUV ZHUH REWDLQHG ZKHQ WKH VXEMHFW ZRUH WKH FRFKOHDU LPSODQW LQ WKH SUHVHQFH RI '$) ,Q WKDW FRQGLWLRQ WKH PHDQ UDQN VFRUHV ZHUH 6$)f DQG '$)f ZLWK DQ (6 YDOXH RI 3HUIRUPDQFH ZLWK &RFKOHDU ,PSODQW 9HUVXV +HDULQJ $LG 7KH VXEMHFWV LQ WKLV VWXG\ ZRUH FRFKOHDU LPSODQWV EHFDXVH WKH\ KDG UHFHLYHG OLWWOH RU QR EHQHILW IURP D KHDULQJ DLG +RZHYHU D ODUJH HIIHFW VL]H ZDV REWDLQHG IRU VRPH RI WKH FRQGLWLRQV ZLWK ERWK WKH FRFKOHDU LPSODQW DQG WKH KHDULQJ DLG $ FRPSDULVRQ RI WKH FRFKOHDU LPSODQW &Of

PAGE 102

1RQH )LJXUH 0HDQ UDQN VFRUHV RI YRZHO HUURUV IRU FRXQWLQJ

PAGE 103

DQG WKH KHDULQJ DLG +$f XQGHU 6$)'$) LV VXPPDUL]HG LQ 7DEOH DQG )LJXUHV 'XUDWLRQ $ UHYLHZ RI UHDGLQJ DQG FRXQWLQJ GXUDWLRQ LQGLFDWHG VPDOO GLIIHUHQFHV LQ PHDQ UDQN VFRUHV IRU UHDGLQJ &O +$ f DQG FRXQWLQJ &O +$ f XQGHU 6$) 7KH (6 YDOXHV UHDGLQJf DQG FRXQWLQJf LQGLFDWHG WKDW WKHUH ZHUH VPDOO GLIIHUHQFHV EHWZHHQ WKH WZR GHYLFHV IRU UHDGLQJ GXUDWLRQ DQG QR GLIIHUHQFHV EHWZHHQ WKH GHYLFHV IRU FRXQWLQJ GXUDWLRQ 7KH '$) UHDGLQJ GXUDWLRQ GDWD UHYHDOHG WKDW WKH PHDQ UDQN VFRUHV IRU WKH FRFKOHDU LPSODQW ZHUH DQG IRU WKH KHDULQJ DLG DQG D YHU\ VPDOO (6 YDOXH RI 7KH '$) FRXQWLQJ GXUDWLRQ GDWD DOVR UHYHDOHG VPDOO GLIIHUHQFHV LQ PHDQ UDQN VFRUHV IRU WKH FRFKOHDU LPSODQW f DQG WKH KHDULQJ DLG f DQG D VPDOO (6 YDOXH f &RQVRQDQW (UURUV 7KH PHDQ UDQN VFRUH IRU FRQVRQDQW HUURUV LQ UHDGLQJ XQGHU 6$) ZDV ZLWK WKH FRFKOHDU LPSODQW DQG ZLWK WKH KHDULQJ DLG \LHOGLQJ D PRGHUDWH (6 YDOXH RI 7KH LQWURGXFWLRQ RI '$) UHVXOWHG LQ RSSRVLWH ILQGLQJV ZLWK WKH FRFKOHDU LPSODQW PHDQ UDQN VFRUH RI DQG WKH KHDULQJ DLG $ PRGHUDWH (6 YDOXH RI ZDV REWDLQHG IRU WKLV FRPSDULVRQ ,Q WKH 6$) FRQGLWLRQ WKH FRXQWLQJ FRQVRQDQW

PAGE 104

7DEOH 0HDQ UDQN VFRUHV DQG HIIHFW VL]H YDOXHV ZLWK WZR DPSOLILFDWLRQ GHYLFHV XQGHU VLPXOWDQHRXV DXGLWRU\ IHHGEDFN 6$)f 'XUDWLRQ 5HDGLQJ &RQVRQDQW (UURUV f 9RZHO (UURUV r&, rr+$ rrr(6 'XUDWLRQ &RXQWLQJ &RQVRQDQW (UURUV 9RZHO (UURUV &O +$ (6 r&, rr+$ rrr(6 &RFKOHDU ,PSODQW +HDULQJ $LG (IIHFW 6L]H

PAGE 105

7DEOH 0HDQ UDQN VFRUHV DQG HIIHFW VL]H YDOXHV ZLWK WZR DPSOLILFDWLRQ GHYLFHV XQGHU GHOD\HG DXGLWRU\ IHHGEDFN '$)f 'XUDWLRQ 5HDGLQJ &RQVRQDQW (UURUV f 9RZHO (UURUV r&, rr+$ rrr(6 'XUDWLRQ &RXQWLQJ &RQVRQDQW (UURUV 9RZHO (UURUV &O +$ (6 r&, rr+$ rrr(6 &RFKOHDU ,PSODQW +HDULQJ $LG (IIHFW 6L]H

PAGE 106

'XUDWLRQ &RQV (UURUV 9RZHO (UURUV )LJXUH &RPSDULVRQ RI UHDGLQJ PHDQ UDQN VFRUHV EHWZHHQ WKH FRFKOHDU LPSODQW &Of DQG WKH KHDULQJ DLG +$f XQGHU VLPXOWDQHRXV DXGLWRU\ IHHGEDFN 6$)f

PAGE 107

'XUDWLRQ &RQV (UURUV 9RZHO (UURUV )LJXUH &RPSDULVRQ RI UHDGLQJ PHDQ UDQN VFRUHV EHWZHHQ WKH FRFKOHDU LPSODQW &Of DQG WKH KHDULQJ DLG +$f XQGHU GHOD\HG DXGLWRU\ IHHGEDFN '$)f

PAGE 108

'XUDWLRQ &RQV (UURUV 9RZHO (UURUV )LJXUH &RPSDULVRQ RI FRXQWLQJ PHDQ UDQN VFRUHV EHWZHHQ WKH FRFKOHDU LPSODQW &Of DQG WKH KHDULQJ DLG +$f XQGHU VLPXOWDQHRXV DXGLWRU\ IHHGEDFN 6$)f

PAGE 109

'XUDWLRQ &RQV (UURUV 9RZHO (UURUV )LJXUH &RPSDULVRQ RI FRXQWLQJ PHDQ UDQN VFRUHV EHWZHHQ WKH FRFKOHDU LPSODQW &Of DQG WKH KHDULQJ DLG +$f XQGHU GHOD\HG DXGLWRU\ IHHGEDFN '$)f

PAGE 110

WDVN \LHOGHG QR GLIIHUHQFHV EHWZHHQ WKH FRFKOHDU LPSODQW DQG WKH KHDULQJ DLG ZLWK VLPLODU PHDQ UDQN VFRUHV IRU ERWK GHYLFHV DQG D VPDOO (6 YDOXH f 9RZHO (UURUV 7KH 6$) UHDGLQJ FRQGLWLRQ \LHOGHG PHDQ UDQN VFRUHV IRU YRZHO HUURUV RI &Of DQG +$f DQG D PRGHUDWH (6 YDOXH f 7KH PHDQ UDQN VFRUHV IRU YRZHO FRXQWLQJ HUURUV XQGHU 6$) ZHUH &Of DQG +$f WKH (6 YDOXH ZDV PRGHUDWH f 7KH '$) UHDGLQJ FRQGLWLRQ \LHOGHG PHDQ UDQN VFRUHV RI &Of DQG +$f 7KH (6 YDOXH IRU WKLV FRPSDULVRQ ZDV ODUJH f &RXQWLQJ YRZHO HUURUV XQGHU '$) LQGLFDWHG VLPLODU PHDQ UDQN VFRUHV &Of DQG +$f ZLWK D VPDOO (6 YDOXH f 6XPPDU\ ,Q VXPPDU\ VWDWLVWLFDO DQDO\VLV RI WKH GDWD GLG QRW UHYHDO VLJQLILFDQW GLIIHUHQFHV LQ GXUDWLRQ RU LQ WKH RFFXUUHQFH RI FRQVRQDQW RU YRZHO HUURUV UHJDUGOHVV RI W\SH RI DPSOLILFDWLRQ RU DXGLWRU\ IHHGEDFN 7KH FRQGLWLRQV \LHOGLQJ D PRGHUDWH WR ODUJH HIIHFW VL]H VXJJHVWHG GLIIHUHQFHV EHWZHHQ WKH FRQGLWLRQV 6$)'$)f DQG WKH GHYLFHV FRFKOHDU LPSODQWKHDULQJ DLGf KRZHYHU EHFDXVH RI WKH VPDOO VDPSOH WKH VWDELOLW\ RI WKH HIIHFW FRXOG QRW EH HYDOXDWHG 3HDUVRQ 3URGXFW0RPHQW FRUUHODWLRQV ZHUH SHUIRUPHG WR HYDOXDWH WHVWUHWHVW UHOLDELOLW\ RI WKH GLIIHUHQFH

PAGE 111

H[SHULPHQWDO FRQGLWLRQV +LJK SRVLWLYH FRUUHODWLRQV ZHUH REWDLQHG IRU DOO WKH FRQGLWLRQV DQG DUH UHSRUWHG LQ 7DEOH $OO RI WKH FRUUHODWLRQV ZHUH VLJQLILFDQW EH\RQG WKH OHYHO RI FRQILGHQFH

PAGE 112

7DEOH &RUUHODWLRQV H[SHULPHQWDO RI WHVWUHWHVW FRQGLWLRQV UHOLDELOLW\ RI &RQGLWLRQ 5HDGLQJ 6LJQLILFDQFH &RXQWLQJ 6LJQLILFDQFH 'XUDWLRQ r r &RQVRQDQW (UURUV r r 9RZHO (UURUV r r r S OHYHO RI VLJQLILFDQFH

PAGE 113

&+$37(5 9 ',6&866,21 5HDGLQJ DQG &RXQWLQJ 'XUDWLRQ 7KH VXEMHFWV LQ WKLV VWXG\ GLG QRW H[KLELW DQ DSSDUHQW '$) HIIHFW LQ GXUDWLRQ RI UHDGLQJ RU FRXQWLQJ EDFNZDUGV LQ WKH DEVHQFH RI DQ\ DPSOLILFDWLRQ QHLWKHU FRFKOHDU LPSODQW QRU KHDULQJ DLGf DV HYLGHQFHG E\ WKH QRQVLJQLILFDQW VWDWLVWLFDO ILQGLQJV IRU WKHVH PHDVXUHV 7KLV FRQFOXVLRQ ZDV IXUWKHU VXSSRUWHG E\ WKH VPDOO HIIHFW VL]H (6f YDOXHV REWDLQHG IRU UHDGLQJ DQG FRXQWLQJ GXUDWLRQ 7KH UHDGHU ZLOO UHFDOO WKDW (6 YDOXHV VXJJHVW WKH OLNHOLKRRG RI D SKHQRPHQRQ EHLQJ SUHVHQW LQ D VDPSOH RU LQ WKLV LQVWDQFH WKH OLNHOLKRRG WKDW UHDGLQJ DQG FRXQWLQJ GXUDWLRQ GLIIHUHQFHV DUH WKH UHVXOW RI FKDQJHV LQ DXGLWRU\ IHHGEDFN 7KH GXUDWLRQ UHVXOWV FRQILUPHG WKH ODFN RI DXGLWRU\ IHHGEDFN IRU VHOIPRQLWRULQJ RI VSHHFK SURGXFWLRQ LQ WKHVH SURIRXQGO\ KHDULQJLPSDLUHG VXEMHFWV /DUJH (6 YDOXHV IRU UHDGLQJ ZLWK WKH FRFKOHDU LPSODQW f DQG WKH KHDULQJ DLG f OHQG VXSSRUW WR WKH SRVVLELOLW\ RI WUXH GLIIHUHQFHV EHWZHHQ WKH 6$) DQG '$) FRQGLWLRQV ([DPLQDWLRQ RI PHDQ UDQN VFRUHV GHPRQVWUDWHG WKDW WKH GLUHFWLRQ RI WKH GLIIHUHQFH ZDV WRZDUG WKH '$) FRQGLWLRQ ZLWK ERWK DPSOLILFDWLRQ GHYLFHV LH VXEMHFWV r f

PAGE 114

WRRN ORQJHU WR UHDG WKH SDVVDJH XQGHU '$) YHUVXV 6$) ZLWK WKH FRFKOHDU LPSODQW DQG ZLWK WKH KHDULQJ DLG 7KLV ILQGLQJ WKDW VXEMHFWV WRRN ORQJHU WR UHDG ZKHQ ZHDULQJ WKH KHDULQJ DLG DJUHHG ZLWK WKH ILQGLQJV RI LQFUHDVHG UHDGLQJ GXUDWLRQ XQGHU '$) E\ KHDULQJLPSDLUHG FKLOGUHQ ZHDULQJ KHDULQJ DLGV UHSRUWHG E\ 0D[RQ HW DO f 6PDOO (6 YDOXHV IRU FRXQWLQJ GXUDWLRQ GLG QRW VWURQJO\ VXSSRUW WKH SRVVLELOLW\ RI DQ HIIHFW GXH WR YDULDWLRQV LQ DXGLWRU\ IHHGEDFN +RZHYHU PHDQ UDQN VFRUHV GLG GHPRQVWUDWH WKDW VXEMHFWV WRRN ORQJHU WR FRXQW XQGHU '$) WKDQ XQGHU 6$) IRU DOO WKUHH FRQGLWLRQV QR DPSOLILFDWLRQ FRFKOHDU LPSODQW DQG KHDULQJ DLGf 0D[RQ HW DO f KDG DOVR UHSRUWHG D '$) HIIHFW ZKHQ WKHLU VXEMHFWV SHUIRUPHG D URWH WDVN RI FRXQWLQJ IURP WR 7KH (6 IRU WKH FRXQWLQJ GXUDWLRQ WDVN ZDV RQO\ LQ WKLV VWXG\ DQG ZRXOG VHHP WR VXJJHVW WKDW WKH OLNHOLKRRG WKDW WKHUH ZDV D '$) HIIHFW ZDV YHUX VPDOO $ UHDVRQ IRU ODFN RI DJUHHPHQW ZLWK WKH 0D[RQ HW DO f VWXG\ LV WKDW WKH FKLOGUHQ LQ WKHLU VWXG\ ZHUH FRXQWLQJ IRUZDUG DQG WKH DGXOWV LQ WKH SUHVHQW VWXG\ ZHUH FRXQWLQJ EDFNZDUG $ UHYLHZ RI WKH '$) OLWHUDWXUH GLG QRW UHYHDO DQ\ VWXGLHV LQYROYLQJ EDFNZDUG FRXQWLQJ DQG WKHUHIRUH QRUPDWLYH GDWD ZHUH QRW DYDLODEOH IRU FRPSDULVRQ +RZHYHU LW LV NQRZQ WKDW VRPH SHRSOH DUH OHVV WR '$) WKDQ RWKHUV HJ %RUGHQ DQG +DUULV f QRWHG WKDW WKH '$) HIIHFW FDQ EH RYHUULGGHQ LI WKH VSHDNHU DWWHQGV WR WKH UHDGLQJ WDVN DQG LJQRUHV WKH DFRXVWLF

PAGE 115

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f $ PRGHUDWH (6 YDOXH f VXJJHVWHG VXSSRUW IRU D SRVVLEOH '$) HIIHFW IRU FRQVRQDQW UHDGLQJ HUURUV ZKHQ WKH VXEMHFWV ZRUH WKH FRFKOHDU LPSODQW 6PDOO (6 YDOXHV ZLWK WKH KHDULQJ DLG f DQG LQ WKH DEVHQFH RI DPSOLILFDWLRQ

PAGE 116

f RQO\ HTXLYRFDOO\ VXJJHVWHG D '$) HIIHFW ([DPLQDWLRQ RI WKH PHDQ UDQN VFRUHV UHYHDOHG WKDW PRUH UHDGLQJ FRQVRQDQW b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f ILUVW IRUPDQW ),f DQG VHFRQG IRUPDQW )f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f RU ZKHQ WKH KHDULQJ DLG ZDV ZRUQ f

PAGE 117

GLG QRW VXJJHVW WKH SRVVLELOLW\ RI D '$) HIIHFW RSHUDWLQJ 7KH SUHVHQFH RI D PRGHUDWH f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f 7KH VXEMHFWV SURGXFHG PRUH YRZHO UHDGLQJ HUURUV XQGHU '$) WKDQ XQGHU 6$) LQ WKH DEVHQFH RI DPSOLILFDWLRQ DQG ZLWK WKH FRFKOHDU LPSODQW $ PRGHUDWH (6 YDOXH f VXSSRUWHG WKH SRVVLELOLW\ RI D '$) HIIHFW ZKHQ WKH VXEMHFWV ZRUH WKH FRFKOHDU LPSODQW 7KH FRFKOHDU LPSODQW FRGLQJ VWUDWHJ\ RI ))) SURYLGHV YLWDO LQIRUPDWLRQ IRU YRZHO SHUFHSWLRQ EHFDXVH YRZHO SHUFHSWLRQ LV FRQWLQJHQW XSRQ )) LQIRUPDWLRQ %DVDO KLJK IUHTXHQF\f HOHFWURGHV DORQJ WKH EDVLODU PHPEUDQH SURYLGH ) LQIRUPDWLRQ DQG DSLFDO ORZ IUHTXHQF\f HOHFWURGHV SURYLGH ), LQIRUPDWLRQ 3DWULFN t

PAGE 118

&ODUN f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f ZDV DSSURDFKLQJ WKH PRGHUDWH UDQJH DQG WKH PHDQ UDQN VFRUH ZDV DOVR LQ WKH GLUHFWLRQ RI PRUH HUURUV XQGHU 6$) WKDQ '$) ,I WKLV HIIHFW VL]H GLG UHSUHVHQW UHDO GLIIHUHQFHV EHWZHHQ WKH 6$)'$) FRQGLWLRQV WKH H[SODQDWLRQ PD\ OLH LQ WKH VXEMHFWVn EHFRPLQJ PRUH IDPLOLDU DQG FRPIRUWDEOH ZLWK WKH EDFNZDUG FRXQWLQJ WDVN 7KH KHDULQJ DLG FRQGLWLRQ LQGLFDWHG QR GLIIHUHQFH EHWZHHQ WKH 6$)'$) FRQGLWLRQV ZLWK D YHU\ VPDOO (6 YDOXH f EHLQJ REWDLQHG 7KH FRFKOHDU LPSODQW FRQGLWLRQ ZDV WKH RSSRVLWH RI WKH KHDULQJ DLG FRQGLWLRQ ZLWK RUH YRZHO HUURUV SURGXFHG LQ WKH '$) FRXQWLQJ FRQGLWLRQ WKDQ LQ WKH 6$) FRQGLWLRQ 7KH SRVVLELOLW\ RI D '$) HIIHFW

PAGE 119

,OO ZDV VWURQJO\ VXSSRUWHG E\ D YHU\ ODUJH (6 YDOXH f 7KH GLIIHUHQFHV EHWZHHQ 6$) DQG '$) IRU WKH FRXQWLQJ YRZHO HUURUV LV WKRXJKW WR EH GXH WR WKH VXEMHFWVn PRQLWRULQJ WKHLU VSHHFK RXWSXW PRUH FORVHO\ WKDQ SUHYLRXVO\ 7KH UHDGHU VKRXOG UHFDOO WKDW WKH VXEMHFWV GHPRQVWUDWHG D PRGHUDWH (6 YDOXH IRU WKH FRQVRQDQW FRXQWLQJ WDVN f DQG DOVR WKDW WKH FRFKOHDU LPSODQW VSHHFK FRGLQJ VWUDWHJ\ SURYLGHV FULWLFDO LQIRUPDWLRQ IRU YRZHO SHUFHSWLRQ ))f 7KHUHIRUH LI D '$) HIIHFW ZDV RFFXUULQJ LW ZRXOG EH DQWLFLSDWHG WKDW LW ZRXOG EH ODUJHU IRU YRZHOV EHFDXVH WKH GHOD\ PD\ KDYH FDXVHG PRUH DXGLWRU\ PLVLQIRUPDWLRQ DQG FRQIXVLRQ IRU WKH VXEMHFWV UHVXOWLQJ LQ D ODUJHU QXPEHU RI YRZHO FRXQWLQJ HUURUV WKDQ FRQVRQDQW FRXQWLQJ HUURUV &RFKOHDU ,PSODQW 9HUVXV +HDULQJ $LG 7KH VXEMHFWVn SHUIRUPDQFH ZLWK WKH FRFKOHDU LPSODQW DQG ZLWK WKH KHDULQJ DLG ZDV HYDOXDWHG XQGHU 6$) DQG '$) 7KH DUHDV HYDOXDWHG ZHUH Df GXUDWLRQ Ef FRQVRQDQW HUURUV DQG Ff YRZHO HUURUV 'XUDWLRQ $ UHYLHZ RI UHDGLQJ GXUDWLRQ PHDQV DQG UDQJHV LQGLFDWHG WKDW WKHUH ZDV QR GLIIHUHQFH EHWZHHQ WKH FRFKOHDU LPSODQW DQG WKH KHDULQJ DLG XQGHU 6$)'$) +RZHYHU PHDQ UDQN VFRUHV LQGLFDWHG WKDW WKH VXEMHFWV WRRN ORQJHU WR UHDG WKH SDVVDJH DQG WR FRXQW LQ ERWK WKH 6$) DQG '$) FRQGLWLRQV ZLWK WKH FRFKOHDU LPSODQW WKDQ ZLWK WKH KHDULQJ DLG (DFK RI WKH

PAGE 120

HLJKW VXEMHFWV LQ WKLV VWXG\ ZDV DEOH WR GHVFULEH WKH GHOD\ ZKHQ ZHDULQJ WKH FRFKOHDU LPSODQW 7KHLU GHVFULSWLRQV RI WKH GHOD\ LQFOXGHG Df 6RXQGV OLNH D WHUULEOH HFKR Ef 6RXQGHG WHUULEOH Ff 0\ YRLFH VRXQGHG ORZHU WKH HFKR VRXQGHG KLJK SLWFK DQG Gf 6HHPV OLNH WKH YRLFH LV FRPLQJ DIWHU PH 2QH RI WKH VXEMHFWV LQTXLUHG XFK GHOD\ RQ LW LWnV WRR PXFK LWn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

PAGE 121

WKH FRFKOHDU LPSODQW SURYLGHG WKH VXEMHFWV ZLWK PRUH DFFXUDWH DXGLWRU\ LQIRUPDWLRQ WKHQ WKH\ UHFHLYHG ZLWK WKH KHDULQJ DLG 7KHUHIRUH XQGHU 6$) WKH\ ZHUH PRQLWRULQJ WKHLU VSHHFK DQG DEOH WR PDLQWDLQ VSHHFK SURGXFWLRQ WDUJHWV 7KLV ZDV PRUH HYLGHQW IRU WKH UHDGLQJ GDWD WKDQ IRU WKH FRXQWLQJ GDWD DJDLQ VXJJHVWLQJ WKH LQIOXHQFH RI WKH WDVN ,Q RWKHU ZRUGV XQGHU FRXQWLQJ WKH VXEMHFWV ZHUH SHUIRUPLQJ D URWH WDVN DQG QRW SD\LQJ DV PXFK DWWHQWLRQ WR WKHLU 9RZHO (UURUV $ FRPSDULVRQ RI YRZHO UHDGLQJ DQG FRXQWLQJ HUURUV ZLWK WKH FRFKOHDU LPSODQW DQG ZLWK WKH KHDULQJ DLG LQGLFDWHG D SDWWHUQ VLPLODU WR WKDW IRXQG IRU WKH FRQVRQDQW HUURUV 7KH VXEMHFWV SURGXFHG IHZHU HUURUV XQGHU 6$) UHIOHFWLQJ WKH TXDOLW\ DQG TXDQWLW\ RI DXGLWRU\ LQIRUPDWLRQ SURYLGHG E\ WKH FRFKOHDU LPSODQW 7KH LQWURGXFWLRQ RI '$) \LHOGHG PRUH ,Q IDFW WKH (6 YDOXH f VXSSRUWHG WKH DUJXPHQW IRU WKH SUHVHQFH RI D '$) HIIHFW 7\SHV RI 6SHHFK (UURUV 2QH RI WKH UHVHDUFK TXHVWLRQV LQ WKLV VWXG\ DGGUHVVHG WKH WRWDO QXPEHU RI FRQVRQDQW DQG YRZHO HUURUV PDGH E\ WKH VXEMHFWV 7KH 3(33(5 SURJUDP DOORZHG WKH W\SH RI HUURUV WR EH LGHQWLILHG DV ZHOO DV WKH QXPEHU RI HUURUV 7KH W\SHV RI HUURUV PDGH E\ WKH VXEMHFWV LQFOXGHG GHOHWLRQV VXEVWLWXWLRQV DQG GLVWRUWLRQV 7KHVH DUH WKH VDPH W\SHV RI

PAGE 122

HUURUV UHSRUWHG E\ )DLUEDQNV DQG *XWWPDQ f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

PAGE 123

7DEOH &RPSDULVRQ RI IUHTXHQF\ DQG W\SH RI UHDGLQJ DQG FRXQWLQJ FRQVRQDQW HUURUV IRU VXEMHFWV XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f DQG ZHDULQJ D FRFKOHDU LPSODQW &Of 7\SH DQG )UHTXHQF\ RI &RQVRQDQW (UURUV &RQGLWLRQ 7DVN 'HOHWLRQV 6XEVWLWXWLRQV 'LVWRUWLRQV 7RWDO &,6$) 5HDGLQJ &,'$) 5HDGLQJ r r r &,6$) &RXQWLQJ &,'$) &RXQWLQJ r r r r /DUJHU QXPEHU RI 6$)'$) SDLU

PAGE 124

7DEOH &RPSDULVRQ RI IUHTXHQF\ DQG W\SH RI UHDGLQJ DQG FRXQWLQJ YRZHO HUURUV IRU VXEMHFWV XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f DQG ZHDULQJ D FRFKOHDU LPSODQW &Of 7\SH DQG )UHTXHQF\ RI 9RZHO (UURUV &RQGLWLRQ 7DVN 'HOHWLRQV 6XEVWLWXWLRQV 'LVWRUWLRQV 7RWDO &,6$) 5HDGLQJ r &,'$) 5HDGLQJ r r r &,6$) &RXQWLQJ &,'$) &RXQWLQJ r r r r /DUJHU QXPEHU RI 6$)'$) SDLU

PAGE 125

7DEOH &RPSDULVRQ RI IUHTXHQF\ RI UHDGLQJ DQG FRXQWLQJ FRQVRQDQW HUURUV IRU VXEMHFWV XQGHU VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ IHHGEDFN 6$)'$)f DQG ZHDULQJ D KHDULQJ DLG +$f 7\SH DQG )UHTXHQF\ RI &RQVRQDQW (UURUV &RQGLWLRQ 7DVN 'HOHWLRQV 6XEVWLWXWLRQV 'LVWRUWLRQV 7RWDO +$6$) 5HDGLQJ r r +$'$) 5HDGLQJ r +$6$) &RXQWLQJ +$'$) &RXQWLQJ r r r /DUJHU QXPEHU RI 6$)'$) SDLU

PAGE 126

7DEOH &RPSDULVRQ RI IUHTXHQF\ DQG W\SH RI UHDGLQJ DQG FRXQWLQJ YRZHO HUURUV IRU VXEMHFWV VLPXOWDQHRXV DQG GHOD\HG DXGLWRU\ XQGHU 6$)'$)f DQG ZHDULQJ D KHDULQJ DLG +$f 7\SH DQG )UHTXHQF\ RI 9RZHO (UURUV &RQGLWLRQ 7DVN 'HOHWLRQV 6XEVWLWXWLRQV 'LVWRUWLRQV 7RWDO +$6$) 5HDGLQJ r r r r +$'$) 5HDGLQJ +$6$) &RXQWLQJ +$'$) &RXQWLQJ r r r r /DUJHU QXPEHU RI 6$)'$) SDLU

PAGE 127

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n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

PAGE 128

7DEOH &RPSDULVRQ RI IUHTXHQF\ DQG W\SH RI UHDGLQJ DQG FRXQWLQJ FRQVRQDQW HUURUV IRU VXEMHFWV ZHDULQJ D FRFKOHDU LPSODQW &Of RU D KHDULQJ DLG +$f 7\SH DQG )UHTXHQF\ RI &RQVRQDQW (UURUV &RQGLWLRQ 7DVN 'HOHWLRQV 6XEVWLWXWLRQV 'LVWRUWLRQV 7RWDO &,6$) 5HDGLQJ +$6$) 5HDGLQJ &,'$) 5HDGLQJ r +$'$) 5HDGLQJ &,6$) &RXQWLQJ +$6$) &RXQWLQJ r &,'$) &RXQWLQJ r +$'$) &RXQWLQJ r r r r r r r r /DUJHU QXPEHU RI &,+$ SDLU

PAGE 129

7DEOH &RPSDULVRQ RI IUHTXHQF\ DQG W\SH RI UHDGLQJ DQ FRXQWLQJ YRZHO HUURUV IRU VXEMHFWV ZHDULQJ D FRFKOHDU LPSODQW &Of RU D KHDULQJ DLG +$f 7\SH DQG )UHTXHQF\ RI &RQVRQDQW (UURUV &RQGLWLRQ 7DVN 'HOHWLRQV 6XEVWLWXWLRQV 'LVWRUWLRQV 7RWDO &,6$) 5HDGLQJ +$6$) 5HDGLQJ r r r &,'$) 5HDGLQJ r +$'$) 5HDGLQJ &,6$) &RXQWLQJ r r +$6$) &RXQWLQJ r &,'$) &RXQWLQJ r r +$'$) &RXQWLQJ r /DUJHU QXPEHU RI &,+$ SDLU

PAGE 130

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

PAGE 131

UHYHUVH ILQGLQJ RI DQ LQFUHDVHG LQ HUURUV ZKHQ WKH\ ZRUH WKH FRFKOHDU LPSODQW XQGHU '$) JDYH VXSSRUW WR WKH SRVLWLRQ WKDW WKHVH VXEMHFWV ZHUH VHOIPRQLWRULQJ WKHLU VSHHFK SURGXFWLRQV DQG WKDW WKH\ ZHUH H[SHULHQFLQJ D '$) HIIHFW DV WKHLU HUURU W\SHV ZHUH VLPLODU WR WKRVH IRU QRUPDOKHDULQJ VXEMHFWV XQGHU '$) UHSRUWHG E\ )DLUEDQNV DQG *XWWPDQ f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

PAGE 132

VXPPDU\ UHDGLQJ DQG FRXQWLQJ GDWD UHIOHFW WKH VDPH SDWWHUQ WKDW ZDV GHPRQVWUDWHG LQ WKH FRQVRQDQW GDWD LH WKH VXEMHFWV PDGH IHZHU HUURUV ZKHQ WKH\ ZRUH WKH FRFKOHDU LPSODQW WKDQ ZKHQ WKH\ ZRUH WKH KHDULQJ DLG LQ WKH 6$) FRQGLWLRQ 7KLV SDWWHUQ ZDV UHYHUVHG ZLWK WKH LQWURGXFWLRQ RI WKH '$) $V ZDV GLVFXVVHG SUHYLRXVO\ WKH W\SH DQG DPRXQW RI DXGLWRU\ IHHGEDFN DYDLODEOH WR WKH VXEMHFWV ZLWK WKH WZR GHYLFHV KHOSHG WR H[SODLQ WKH GLUHFWLRQ RI WKH HUURU SDWWHUQV 7KH VXEMHFWVn DOVR JDYH VXSSRUW WR WKH SRVLWLRQ WKDW WKH\ ZHUH H[SHULHQFLQJ VRPH GHJUHH RI '$) HIIHFW 6XPPDU\ 7KH SXUSRVH RI WKLV VWXG\ ZDV WR LQYHVWLJDWH WKH HIIHFW RI GHOD\HG DXGLWRU\ IHHGEDFN '$)f RQ WKH VSHHFK SURGXFWLRQ RI DGXOW SRVWOLQJXDOO\ GHDIHQHG FRFKOHDU LPSODQW XVHUV 7KH IROORZLQJ ZDV IRXQG 'XUDWLRQf§6$)'$) 7KH VXEMHFWV WRRN ORQJHU WR UHDG WKH *UDQGIDWKHU 3DVVDJH XQGHU '$) WKDQ XQGHU 6$) ZLWK WKH FRFKOHDU LPSODQW DQG WKH KHDULQJ DLG 7KHUH ZDV QR DSSDUHQW GLIIHUHQFH LQ FRXQWLQJ GXUDWLRQ EHWZHHQ 6$) DQG '$) 7KH VXEMHFWV SURGXFHG PRUH FRQVRQDQW UHDGLQJ HUURUV XQGHU '$) WKDQ 6$) ZLWK WKH FRFKOHDU LPSODQW DQG WKH KHDULQJ DLG 0RUH YRZHO UHDGLQJ HUURUV ZHUH SURGXFHG XQGHU '$) WKDQ 6$) ZLWK WKH FRFKOHDU LPSODQW EXW

PAGE 133

IHZHU HUURUV XQGHU '$) ZLWK WKH KHDULQJ DLG 0RUH FRQVRQDQW FRXQWLQJ HUURUV ZHUH SURGXFHG XQGHU '$) WKDQ 6$) ZKHQ WKH VXEMHFWV ZHUH ZHDULQJ HLWKHU WKH FRFKOHDU LPSODQW RU WKH KHDULQJ DLG 7KH VXEMHFWV SURGXFHG PRUH YRZHO FRXQWLQJ HUURUV ZLWK WKH FRFKOHDU LPSODQW XQGHU '$) WKDQ 6$) 7KH\ SURGXFHG PRUH YRZHO HUURUV LQ WKH 6$) WKDQ '$) ZKHQ WKH\ ZRUH WKH KHDULQJ DLG 'XUDWLRQf§&RFKOHDU ,PSODQW+HDULQR $LG 7KHUH ZDV QR GLIIHUHQFH EHWZHHQ WKH GXUDWLRQ RI UHDGLQJ DQG FRXQWLQJ ZLWK WKH FRFKOHDU LPSODQW YHUVXV WKH KHDULQJ DLG 7KH VXEMHFWV WRRN ORQJHU WR UHDG WKH SDVVDJH DQG FRXQW EDFNZDUG XQGHU '$) WKDQ 6$) ZLWK ERWK WKH FRFKOHDU LPSODQW DQG ZLWK WKH KHDULQJ DLG 7RWDO 1XPEHU RI (UURUVf§&RFKOHDU ,PSODQW+HDULQD $LG 7KH VXEMHFWV PDGH PRUH FRQVRQDQW DQG YRZHO UHDGLQJ HUURUV XQGHU '$) ZLWK WKH FRFKOHDU LPSODQW WKDQ WKH KHDULQJ DLG 7KHUH ZHUH QR GLIIHUHQFHV EHWZHHQ WKH FRFKOHDU LPSODQW DQG WKH KHDULQJ DLG LQ WKH RFFXUUHQFH RI FRQVRQDQW DQG YRZHO HUURUV 0RUH YRZHO FRXQWLQJ HUURUV ZHUH SURGXFHG XQGHU '$) WKDQ 6$) ZKHQ WKH ZRUH WKH FRFKOHDU LPSODQW DQG ZKHQ WKH\ ZRUH WKH KHDULQJ DLG ,

PAGE 134

&RQFOXVLRQV $OWKRXJK WKH ILQGLQJV LQ WKLV VWXG\ ZHUH QRW VWDWLVWLFDOO\ VLJQLILFDQW FRPSHOOLQJ HYLGHQFH ZDV DYDLODEOH LQ WHUPV RI PRGHUDWH WR ODUJH HIIHFW VL]H YDOXHV IRU VRPH H[SHULPHQWDO FRQGLWLRQV HJ UHDGLQJ GXUDWLRQf LQGLFDWLQJ WKH H[LVWHQFH RI D '$) HIIHFW +RZHYHU WKH VWDELOLW\ RI WKH HIIHFW VL]H FRXOG QRW EH GHPRQVWUDWHG GXH WR WKH VPDOO VDPSOH VL]H DQG WKH LQDELOLW\ WR SHUIRUP IXUWKHU VWDWLVWLFDO DQDO\VLV RQ WKH GDWD ([DPLQDWLRQ RI PHDQ UDQN VFRUHV DOVR VXSSRUWHG WKH SRVVLELOLW\ WKDW D '$) HIIHFW ZDV RFFXUULQJ $GGLWLRQDO LQGLFDWLRQV RI VXSSRUW IRU WKH SUHVHQFH RI D '$) HIIHFW RQ WKH VSHHFK SURGXFWLRQ RI WKHVH VXEMHFWV LQFOXGHG 7KH VXEMHFWVn GHVFULSWLRQV RI WKHLU DXGLWRU\ IHHGEDFN XQGHU '$) 7KH WUDQVFULEHUVn REVHUYDWLRQV RI GLIIHUHQFHV LQ WKH VXEMHFWVn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

PAGE 135

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nV DXGLWRU\ IHHGEDFN ZRXOG WKH HIIHFW RQ UHDGLQJ GXUDWLRQ EH VLPLODU WR WKDW IRXQG IRU WKHVH FRFKOHDU LPSODQW XVHUV LQ WKH KHDULQJ DLG '$) FRQGLWLRQ" H

PAGE 136

$33(1',; 727$/ 180%(5 2) &21621$17 (55256 '85,1* 5($',1* 6XEMHFW &RFKOHDU 2Q ,PSODQW 2II +HDULQJ $LG 2Q 6$) '$) 6$) '$) 6$) '$) 7RWDO

PAGE 137

$33(1',; 727$/ 180%(5 2) 92:(/ (55256 '85,1* 5($',1* 6XEMHFW &RFKOHDU 2Q ,PSODQW 2II +HDULQJ $LG 2Q f 6$) '$) 6$) '$) 6$) '$) 7RWDO

PAGE 138

$33(1',; 727$/ 180%(5 2) &21621$17 (55256 '85,1* &2817,1* 6XEMHFW &RFKOHDU 2Q ,PSODQW 2II +HDULQJ $LG 2Q 6$) '$) 6$) '$) 6$) '$) 7RWDO

PAGE 139

$33(1',; 727$/ 180%(5 2) 92:(/ (55256 '85,1* &2817,1* 6XEMHFW &RFKOHDU 2Q ,PSODQW 2II +HDULQJ $LG 2Q 6$) '$) 6$) '$) 6$) '$) 7RWDO

PAGE 140

$33(1',; '85$7,21 ,1 6(&21'6 '85,1* 5($',1* 6XEMHFW &RFKOHDU 2Q ,PSODQW 2II +HDULQJ 2Q $LG f 6$) '$) 6$) '$) 6$) '$) f f Ur LQ 7RWDO

PAGE 141

$33(1',; '85$7,21 ,1 6(&21'6 '85,1* &2817,1* 6XEMHFW &RFKOHDU 2Q ,PSODQW 2II +HDULQJ $LG f 2Q 6$) '$) 6$) '$) 6$) '$) 7RWDO

PAGE 142

5()(5(1&(6 $PHULFDQ 1DWLRQDO 6WDQGDUGV ,QVWLWXWH f 0HWKRGV RI PHDVXUHPHQW RI HOHFWRDFRXVWLFDO FKDUDFWHULVWLFV RI KHDULQJ DLGV $16, 6 f 1HZ
PAGE 143

IHHGEDFN 'RFWRUDO GLVVHUWDWLRQ 2KLR 6WDWH 8QLYHUVLW\ f 'LVVHUWDWLRQ $EVWUDFWV ,QWHUQDWLRQDO %f &DOYHUW 5 f LPSDLUPHQW ,Q 1 $UWLFXODWLRQ DQG KHDULQJ /DVV / 9 1RWKHUQ KHDULQ
PAGE 144

'RQ DQ 0 ) 'DQNRZVLN 0F&DQGOHVV t 6PLWK / f ,GHQWLILFDWLRQ RI V\QWKHWLF YRZHOV E\ SDWLHQWV XVLQJ WKH 6\PELRQ FRFKOHDU LPSODQW (DU DQG +HDULQJ 'RZHOO 5 & 6HOLJPDQ % ( %ODUQH\ 3 t &ODUN 0 f 6SHHFK SHUFHSWLRQ XVLQJ D WZRIRUPDQW HOHFWURGH FRFKOHDU SURVWKHVLV LQ TXLHW DQG QRLVH $FWD 2WRODU\QJRO (GGLQJWRQ 0D\f &RPSDULVRQ RI VLQJOHFKDQQHO DQG PXOWLSOHFKDQQHO LPSODQWV ,Q 5 .RKXW &KDLUf &RFKOHDU ,PSODQWV 1,+ &RQVHQVXV 'HYHORSPHQW :DVKLQJWRQ '& (JXFKL 6 t +LUVK f 'HYHORSPHQW RI VSHHFK VRXQGV LQ FKLOGUHQ $FWD 2WRODUYQDRO 6XSSO f (LVHQEHUJ / 6 %HUOLQHU +RXVH : ) t (GJHUWRQ % f 6WDWXV RI WKH DGXOWVn DQG FKLOGUHQnV FRFKOHDU LPSODQW SURJUDPV DW WKH +RXVH (DU ,QVWLWXWH $QQDOV RI WKH 1HZ
PAGE 145

)UDYHO 5 3 VLPSOH e f f &RFKOHDU LPSODQW HOHFWURQLFV PDGH 7KH 2WRODU\QJRORJLF &OLQLFV RI 1RUWK $PHULFD *D\ 7 f $ SHUFHSWXDO VWXG\ RI $PHULFDQ (QJOLVK GLSKWKRQJV /DQJXDJH DQG 6SHHFK *LEVRQ : 3 5 f DQG *URYHV (GV HGf SS f &RFKOHDU LPSODQWV ,Q $ ( 6FRWW%URZQnV RWRODU\QJRORJ\ %RVWRQ %XWWHUZRUWKV WK *RHKO + t .DXIPDQ f 'R WKH HIIHFWV RI DGYHQWLWLRXV GHDIQHVV LQFOXGH GLVRUGHUHG VSHHFK" -RXUQDO RI 6SHHFK DQG +HDULQJ 'LVRUGHUV *ROG 7 f 6SHHFK SURGXFWLRQ LQ KHDULQJL FKLOGUHQ -RXUQDO RI &RPPXQLFDWLRQ 'LVRUGHUV *ROGVWHLQ 0 t )ULHGHOZDOG : 7 f &RFKOHDU LPSODQWV 1DWLRQDO ,QVWLWXWHV RI +HDOWK &RQVHQVXV 'HYHORSPHQW &RQIHUHQFH 6WDWHPHQW f +DUULQJWRQ f 6WXWWHULQJ GHOD\HG DXGLWRU\ IHHGEDFN DQG OLQJXLVWLF UK\WKP -RXUQDO RI 6SHHFK DQG +HDULQJ 5HVHDUFK & $FNHUPDQ % / &KDSSHOO & 5 +HDOH\ : / t 6WRUPHU f FRPPXQLFDWLYH GLVRUGHUV $ UHYLHZ RI WKH 7KH SUHYDOHQFH RI )LQDO 5HSRUWf 5RFNYLOOH 0DU\ODQG $PHULFDQ 6SHHFK /DQJXDJH+HDULQJ $VVRFLDWLRQ +HJGH 0 f &OLQLFDO UHVHDUFK LQ FRPPXQLFDWLYH GLVRUGHUV 3ULQFLSOHV DQG VWUDWHJLHV SS f %RVWRQ &ROOHJH+LOO 3UHVV +ROPHV $ ( .HPNHU ) t 0HUZLQ ( f 7KH HIIHFWV RI YDU\LQJ WKH QXPEHU RI FRFKOHDU LPSODQW RQ VSHHFK SHUFHSWLRQ $PHULFDQ -RXUQDO RI 2WRORJ\ +RSNLQV 1 7 &KDLUf FRFKOHDU LPSODQWV 5HSRUW RI WKHDG KRF FRLWX $6+$ f LWWHH RQ +RXVH : ) f &RFKOHDU LPSODQWV $QQDOV RI 2WRODU\QJRORJ\ 5KLQRORJY DQG /DU\QJRORJ\ 6XSSO f +XFN 6 : &RUPLHU :+ t %RXQGV :* -U f 5HDGLQJ 6WDWLVWLFV DQG 5HVHDUFK SS f 1HZ
PAGE 146

+XGJLQV & 9 t 1XPEHUV ) & f $Q LQYHVWLJDWLRQ RI LQWHOOLJLELOLW\ RI VSHHFK RI WKH GHDI *HQHWLF 3V\FKRORJ\ 0RQRJUDSKV +XPHV / ( t %HVV ) + f 7XWRULDO RQ WKH SRWHQWLDO GHWHULRUDWLRQ LQ KHDULQJ GXH WR KHDULQJ DLG XVDJH -RXUQDO RI 6SHHFK DQG +HDULQJ 5HVHDUFK f .HVVOHU f 3UHVHQW VWDWXV RI FRFKOHDU LPSODQWV LQ FKLOGUHQ ,Q ( 2ZHQV t .HVVOHU (GVf &RFKOHDU ,PSODQWV LQ
PAGE 147

/LQJ t /LQJ $ + f $XUDO K£ELOLWDWLRQ 7KH RI YHUEDO OHDUQLQJ LQ KHDULQJLPSDLUHG SS f :DVKLQJWRQ '& 7KH $OH[DQGHU *UDKDP %HOO $VVRFLDWLRQ IRU WKH 'HDI / t $EUDPVRQ $ f VWXG\ RI YRLFLQJ LQ LQLWLDO :RUG $ FURVVODQJXDJH $FRXVWLFDO f RUSKRV 0DF.D\ LQWHUQDO $JHOLQNHG FKDQJHV LQ WKH GHOD\ LQ DXGLWRU\ IHHGEDFN WKDW SURGXFHV PD[LPDO GLVUXSW 7KH $FRXVWLFDO 6RFLHW\ RI $PHULFD 0DF.D\ 5 $ f 3KRQHWLFV 7KH VFLHQFH RI VSHHFK SURGXFWLRQ QG HGf SS f %RVWRQ $ &ROOHJH+LOO 3XEOLFDWLRQ /LWWOH %URZQ DQG &RPSDQ\ 0DUDVFXLOR / $ t 0F6ZHHQH\ 0 f DQG GLVWULEXWLRQIUHH PHWKRGV IRU WKH SS f 0RQWHUH\ &DOLIRUQLD 3XEOLVKLQJ &R %URRNV&ROH 0DUWLQ ) 1 f ,QWURGXFWLRQ WR DXGLRORJ\ UG HGf (QJOHZRRG &OLIIV 13UHQWLFH+DOO 0D[RQ $ % %UDFNHWW 5LRUGDQ $ t 3IHIIHU ( % 1RYHPEHUf 0D[LPL]LQJ UHVLGXDO KHDULQJ $VVHVVLQJ DQG PDQDJLQJ KHDULQJLPSDLUHG FKLOGUHQ 3DSHU SUHVHQWHG DW WKH PHHWLQJ RI WKH $PHULFDQ 6SHHFK /DQJXDJH+HDULQJ $VVRFLDWLRQ 1HZ 2UOHDQV /$ 0F*DUU 1 6 FRQWURO t +DUULV 6 LQ D GHDI VSHDNHU f $UWLFXODWRU\ 0 2VEHUJHU SS f ,Q +RFKEHUJ + /HYLWW (GVf 6SHHFK RI WKH +HDULQJ,PSDLUHG %DOWLPRUH 8QLYHUVLW\ 3DUN 3UHVV 0HGZHWVN\ / +DQLQ / t %RRWKUR\G $ & f 2EMHFWLYH FKDQJHV LQ WKH VSHHFK RI FRFKOHDU L 3DSHU SUHVHQWHG DW WKH DQQXDO FRQYHQWLRQ RI $PHULFDQ 6SHHFK/DQJXDJH+HDULQJ $VVRFLDWLRQ 1HZ 2UOHDQV /$ 0LOOHU $ t 1LFHOH\ 3 ( f $Q DQDO\VLV RI SHUFHSWXDO FRQIXVLRQV DPRQJ VRPH (QJOLVK FRQVRQDQWV RI WKH $PHULFDQ $FRXVWLFDO 6RFLHW\ 0LPHV 0 $ +DQVRQ % ) t 6KRXS ( f )UHTXHQF\ RI RFFXUUHQFH RI SKRQHPHV LQ FRQYHUVDWLRQDO (QJOLVK /DQJXDJH DQG 6SHHFK

PAGE 148

f 0RQVHQ 5 % LPSDLUHG FKLOGUHQ 7RZDUG PHDVXULQJ KRZ ZHOO KHDULQJ MRXUQDO RI 6SHHFK DQG +HDULQ 0RQVHQ 5 % f SKRQDWLRQ DQG DUWLFXODWLRQ t 0 RI GHDIQHVV RQ ,Q +LFKEHUJ + /HYLWW (GVf 6SHHFK RI WKH +HDULQJ ,PSDLUHG SS f %DOWLPRUH 8QLYHUVLW\ 3DUN 1DWLRQDO &HQWHU IRU +HDOWK 6WDWLVWLFV f >8QSXEOLVKHG GDWD IURP WKH 1DWLRQDO +HDOWK ,QWHUYLHZ 6XUYH\@ 1LFRORVL / +DUU\PDQ ( t .UHVKHFN f 7HUPLQRORJ\ RI FRPPXQLFDWLRQ GLVRUGHUV ODQJXDJHKHDULQJ UG HGf S :LOOLDPV DQG :LONLQV f %DOWLPRUH 2n&RQQRU *HUVWPDQ ) 6 / /LEHUPDQ $ 0 'HODWWUH f $FRXVWLF FXHV IRU WKH 3 & t SHUFHSWLRQ RI LQLWLDO ZMU LQ (QJOLVK :RUG 2VWHU $ f &KDQJHV LQ VSHHFK ZLWK XVH RI DQ LPSODQW 6WRFNKRO 3UR DQG 6WDWXV 5HSRUWV 6SHHFK 7UDQVPLVVLRQ /DERUDWRU\ 5R\DO ,QVWLWXWH RI 7HFKQRORJ\ 2ZHQV ( .HVVOHU 7HOOHHQ & t 6FKXEHUW ) f 7KH 0LQLPDO $XGLWRU\ &DSDELOLWLHV %DWWHU\ 6W /RXLV $XGLWHF 3DWULFN ) t &ODUN 0 f 7KH QXFOHXV FKDQQHO FRFKOHDU LPSODQW V\VWHP (DU DQG +HDULQJ f 66 3HUNLQV : + t .HQW 5 f )XQFWLRQDO DQDWRP\ RI VSHHFK ODQJXDJH DQG KHDULQJ $ SULPHU SS f 6DQ 'LHJR &$ &ROOHJH+LOO 3UHVV 3ODQW f 7KH HIIHFW RI DQ DFTXLUHG SURIRXQG KHDULQJ ORVV RQ VSHHFK SURGXFWLRQ $ FDVH VWXG\ %ULWLVK -RXUQDO RI $XGLRORJ\ 3XQFK f 7KH SUHYDOHQFH RI KHDULQJ LPSDLUPHQW $6+$ f 6H\IULHG 1 +XWFKLQVRQ 0 t 6PLWK / / f /DQJXDJH DQG VSHHFK RI WKH KHDULQJ LPSDLUHG ,Q 5 /

PAGE 149

6FKRZ t 0 $ 1HUERQQH (GVf ,QWURGXFWLRQ WR $XUDO QG HGf SS f $XVWLQ 7; 3UR(G 6FKULEHUJ / f 3URJUDPV WR H[DPLQH SKRQHWLF DQG SKRQRORJLF HYDOXDWLRQ UHFRUGV 3(33(5f 9HUVLRQ >&RPSXWHU SURJUDP@ 0DGLVRQ :LVFRQVLQ 'HYHORSPHQW DQG 'LVWULEXWLRQ &HQWHU 8QLYHUVLW\ RI :LVFRQVLQ0DGLVRQ f 6FKULEHUJ / .ZLDWNRZVNL t +RIIPDQQ $ SURFHGXUH IRU SKRQHWLF WUDQVFULSWLRQ E\ FRQVHQVXV -6+5 6LPPRQV ) % f (OHFWULFDO VWLPXODWLRQ RI WKH DXGLWRU\ QHUYH LQ PDQ $UFKLYHV RI 2WRODU\QJRORJ\ 6NLQQHU 0 : f 7KH KHDULQJ RI VSHHFK GXULQJ ODQJXDJH DFTXLVLWLRQ 7KH 2WRODU\QJRORJLF &OLQLFV RI 1RUWK $PHULFD f 6NLQQHU 0 : +ROGHQ / +ROGHQ 7 $ 'RZHOO 5 & 6HOLJPDQ 3 0 %ULPDFRPEH $ t %HLWHU $ / f 3HUIRUPDQFH RI SRVW OLQJXDOO\ GHDI DGXOWV ZLWK ZHDUDEOH VSHHFK SURFHVVRU :63,,,f DQG PLQL VSHHFK 063f RI WKH 1XFOHXV PXOWLHOHFWURGH FRFKOHDU LPSODQW (DU DQG +HDULQJ f 6PLWK & 5 f 5HVLGXDO KHDULQJ DQG VSHHFK SURGXFWLRQ LQ GHDI FKLOGUHQ -RXUQDO RI 6SHHFK DQG +HDULQJ 5HVHDUFK 6WUDQJH : -HQNLQV t -RKQVRQ 7 / f '\QDPLF VSHFLILFDWLRQV RI FRDUWLFXODWHG YRZHOV -RXUQDO RI WKH $FRXVWLFDO 6RFLHW\ RI $PHULFD 6WXGGHUW.HQQHG\ 0 f 6SHHFK SHUFHSWLRQ +DVNLQV VWDWXV UHSRUW 65 7\H0XUUD\ 1 /RZGHU 0 t 7\OHU 5 6 f &RPn SDULVRQ RI WKH )2) DQG ))) SURFHVVLQJ VWUDWHJLHV IRU WKH &RFKOHDU &RUSRUDWLRQ FRFKOHDU LPSODQW (DU DQG +HDULQJ f 7\H0XUUD\ 1 t 7\OHU 5 6 f $XGLWRU\ FRQVRQDQW DQG ZRUG UHFRJQLWLRQ VNLOOV RI FRFKOHDU LPSODQW XVHUV (DU DQG +HDULQJ }

PAGE 150

:DOW]PDQ t +RFKEHUJ f 3HUFHSWLRQ RI VSHHFK XVLQJ D PXOWLFKDQQHO FRFKOHDU LQSXW
PAGE 151

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

PAGE 152

, FHUWLI\ WKDW KDYH UHDG WKLV VWXG\ DQG WKDW LQ P\ RSLQLRQ LW FRQIRUPV WR DFFHSWDEOH VWDQGDUGV RI VFKRODUO\ SUHVHQWDWLRQ DQG LV IXOO\ DGHTXDWH LQ VFRSH DQG TXDOLW\ DV D GLVVHUWDWLRQ IRU WKH GHJUHH RI 'RFWRU RI 3KLORVRSK\ V &KDLUPDQ RI &RPPXQLFDWLRQ DQG 'LVRUGHUV FHUWLI\ WKDW KDYH UHDG WKLV VWXG\ DQG WKDW LQ P\ RSLQLRQ LW FRQIRUPV WR DFFHSWDEOH VWDQGDUGV RI VFKRODUO\ SUHVHQWDWLRQ DQG LV IXOO\ DGHTXDWH LQ VFRSH DQG TXDOLW\ DV D GLVVHUWDWLRQ IRU WKH GHJUHH RI 'RFWRU RI 3KLORVRSK\ $OLFH 7 '\VRQ &KDLUPDQ RI &RPPXQLFDWLRQ DQG FHUWLI\ WKDW KDYH UHDG WKLV VWXG\ DQG WKDW LQ P\ RSLQLRQ LW FRQIRUPV WR DFFHSWDEOH VWDQGDUGV RI VFKRODUO\ SUHVHQWDWLRQ DQG LV IXOO\ DGHTXDWH LQ VFRSH DQG TXDOLW\ DV D GLVVHUWDWLRQ IRU WKH GHJUHH RI 'RFWRU RI 3KLORVRSK\ DQG 'LVRUGHUV FHUWLI\ WKDW KDYH UHDG WKLV VWXG\ DQG WKDW LQ P\ RSLQLRQ LW FRQIRUPV WR DFFHSWDEOH VWDQGDUGV RI VFKRODUO\ SUHVHQWDWLRQ DQG LV IXOO\ DGHTXDWH LQ VFRSH DQG TXDOLW\ DV D GLVVHUWDWLRQ IRU WKH GHJUHH RI 'RFWRU RI 3KLORVRSK\ $VVRFLDWH 3URIHVVRU RI &RPPXQLFDWLRQ 3URFHVVHV DQG 'LVRUGHUV

PAGE 153

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

PAGE 154

81,9(56,7< 2) )/25,'$


THE EFFECT OF DAF ON SPEECH PRODUCTION OF POST-LINGUAL
COCHLEAR IMPLANT USERS
By
POLLY SHIPP GREY
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF
THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1992
¡UNIVERSITY OF FLORIDA LIBRARIES

DEDICATION
This dissertation is lovingly dedicated to
Edward Crawford Shipp
Polly Moore Shipp
(1911-1963)
Edward Rodgers Grey
Virginia Farrell Grey

ACKNOWLEDGEMENTS
I wish to express my deepest appreciation and gratitude
to Dr. Patricia B. Kricos for her outstanding guidance, and
steadfast encouragement during my graduate studies and
throughout this project. I am also indebted to Dr. Alice T.
Dyson for her many contributions to the completion of this
project. I wish to thank the other members of my committee
who have given so generously of their time, shared their
knowledge, and have been so supportive of me during my
graduate studies, Dr. Alice E. Holmes, Dr. F. J. Kemker, and
Dr. Otto von Mering.
I would also like to express my thanks to Dr. Kenneth
Gerhardt, Dr. Michael Crary, and Ernest Walden for their
assistance with calibration, resolving instrumentation
problems, and collection of pilot data.
I am grateful to Phonic Ear Corporation and Unitron
Industries, Incorporated for loaning me the necessary
equipment and for their understanding when data collection
took longer than anticipated. I am especially grateful to
Robert Mendoza of Phonic Ear Corporation and John Seamans of
Unitron Industries Incorporated for their interest,
assistance, and patience in working out equipment problems
during the early part of the research.
iii

I would like to express my gratitude to Mrs. Ruby
Moore, of J & R Enterprises, for her contribution to the
completion of this project in typing the final manuscript.
Special thanks go to Kit Evans Brinsko for her
friendship, her sense of humor, and for the many hours she
contributed in helping transcribe the data.
I must also thank some others whose friendship has been
so steadfast, Ann Pierson, Darlene Hooker, Lori Gonzalez,
and Jamie Barron Schwartz.
I want to thank my family for their encouragement and
support, especially Watkins Adams Saunders, Jr.
Finally, I give my love and thanks to my husband,
Barry, who fills my life with so much happiness.
IV

TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS Ui
ABSTRACT vii
CHAPTERS
I INTRODUCTION 1
II REVIEW OF THE LITERATURE 7
Hearing 8
Normal Speech Production and
Perception 9
Vowels 10
Consonants 11
Effect of Hearing Loss on Speech
Production and Perception 13
Cochlear Implants 25
Differences in Cochlear Implants 26
Delayed Auditory Feedback 41
Summary 4 7
III METHODOLOGY 4 9
Subjects 49
Test Procedures 50
Equipment 57
Conditions 62
Methods and Materials 62
Analysis of Data 65
IV RESULTS 70
DAF Effect on Reading and Counting
Duration 71
DAF Effect on Number of Consonant
and Vowel Errors 81
Performance with Cochlear Implant
Versus Hearing Aid 93
Summary 102
v

V DISCUSSION 105
Reading and Counting Duration 105
Consonant Errors 107
Vowel Errors 109
Cochlear Implant Versus Hearing Aid m
Types of Speech Errors 113
Summary 124
Conclusions 126
APPENDIX 1: TOTAL NUMBER OF CONSONANT ERRORS
DURING READING 128
APPENDIX 2: TOTAL NUMBER OF VOWEL ERRORS DURING
READING 129
APPENDIX 3: TOTAL NUMBER OF CONSONANT ERRORS
DURING COUNTING 130
APPENDIX 4: TOTAL NUMBER OF VOWEL ERRORS DURING
COUNTING 131
APPENDIX 5: DURATION, IN SECONDS, DURING
READING 132
APPENDIX 6: DURATION, IN SECONDS, DURING
COUNTING 13 3
REFERENCES 134
BIOGRAPHICAL SKETCH 143
vi

Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
THE EFFECT OF DAF ON SPEECH PRODUCTION OF POST-LINGUAL
COCHLEAR IMPLANT USERS
By
Polly Shipp Grey
May, 1992
Chairman: Patricia B. Kricos, Ph.D.
Co-Chairman: Alice T. Dyson, Ph.D.
Major Department: Communication Processes and Disorders
The purpose of this study was to investigate the effect
of delayed auditory feedback (DAF) on the speech production
of adult post-lingually deafened cochlear implant users.
Delayed auditory feedback effects on the speech production
of normal-hearing individuals are well documented and have
also been reported in a group of hearing-impaired children
using hearing aids. The eight subjects, five women and
three men, ranged in aged from 31 to 61 years. All wore the
Cochlear Corporation Nucleus 22-Channel cochlear implant and
had completed the recommended post-implant aural
rehabilitation protocol.
The subjects were tested under simultaneous auditory
feedback (SAF) and delayed auditory feedback (DAF) in three
conditions: (a) cochlear implant, (b) hearing aid, and (c)
no amplification. In each condition they read a passage and
counted backwards from 100 to 70. The subjects' speech
samples were transcribed using the International Phonetic
vii

Alphabet and were analyzed for total number of consonant and
vowel errors using the Program to Examine Phonetic and
Phonologic Evaluation Records (PEPPER). Differences between
the SAF and DAF conditions in the duration of reading and of
counting were also measured in seconds.
The data were subjected to a Friedman Two-Way Analysis
of Variance (ANOVA). There were no statistically
significant differences in performance regardless of the
task or condition, suggesting the absence of a DAF effect.
However, an apparent DAF effect was detected during
transcription of the recorded data. This was investigated
further by calculating effect size values between SAF/DAF
and the different experimental tasks. Large effect size
values under DAF were obtained for: (a) reading duration
with the cochlear implant (0.96) and the hearing aid (0.99)
and (b) counting vowel errors (1.02) with the cochlear
implant. These large effect sizes indicated that subjects
took longer to read the passage when wearing either device
and more vowel counting errors were made when wearing the
cochlear implant. Effect size value comparisons between the
two devices indicated a large DAF effect size (0.81) for
vowel reading errors with the cochlear implant. In summary
a possible DAF effect was evident in some conditions but was
not supported by statistical testing.
Vlll

CHAPTER I
INTRODUCTION
The most prevalent chronic disability in the population
of the United States is hearing impairment (Punch, 1983).
It is estimated that 17.4 million Americans have some degree
of hearing loss and approximately 1% of these people are
profoundly hearing impaired, i.e., deaf (National Center for
Health Statistics, 1982). In this group of profoundly
hearing-impaired people are some who no longer receive, or
have never received, benefit from conventional amplifica¬
tion. The reasons for this vary but include increases in
symptoms of tinnitus or vertigo and an intolerance to
vibrotactile sensations that can accompany the use of
powerful amplification (Eisenberg, Berliner, House, and
Edgerton, 1983) as well as the risk of causing additional
damage to the ear (Humes & Bess, 1981) . Lastly, there is,
in some cases of profound hearing loss, the inability to
overcome the hearing loss via amplification. The critical
influence of hearing, and the effects of varying degrees of
hearing loss, on the acquisition of speech and language is
well established (Calvert & Silverman, 1983; Gold, 1980;
Hudgins & Numbers, 1942; Levitt, McGarr, & Geffner, 1987;
Monsen, 1978; Smith, 1975). Research into the speech
1

2
production of the post-lingually hearing impaired, i.e.,
individuals who developed hearing loss after acquiring
speech and language, has been described as to "generally
consist[ing] of anecdotal reports" (Seyfried, Hutchinson, &
Smith, 1989). However, a comparison study of articulatory
patterns in a normal-hearing and a post-lingually deafened
adult, by Zimmerman and Rettaliata (1981), suggested the
importance of auditory information in monitoring and
maintaining "speech coordinative structures." Boothroyd
(1988) cited the significant role of hearing as a feedback
system for conservation and restoration of speech in the
post-lingually hearing impaired. As was stated earlier,
some hearing-impaired individuals no longer receive, or have
never received, benefit from conventional amplification.
These people no longer have access to the feedback system to
which Boothroyd was referring. The cochlear implant offers
an alternative to conventional amplification.
In 1957 Djourno and Eyries reported their findings
following stimulation of the acoustic nerve by the direct
application of an electrode (Simmons, 1966). Their patient,
a 50-year-old deaf man, described sound sensations he
experienced as sounding like "crickets" or a "roulette
wheel." In addition he reported an awareness of background
sounds, and his increased awareness of speech rhythm enabled
him, in time, to improve his speechreading skills. This
encouraging news, along with advances in the surgical

3
techniques and the design of stimulating devices, resulted
in interest by others in the medical community. By 1969 Dr.
William F. House and Jack Urban, an electrical engineer, had
developed the first cochlear implant in the United States
(House, 1976). Cochlear implants are surgically implanted
devices that allow the profoundly hearing impaired to
experience sound. The first implants used a single
electrode (channel) but, with better technology and
continuing research, some of today's devices make use of
multiple electrodes (multichannel). All of the implants
enable the user to experience sound sensation by stimulating
the auditory nerve. Today there are more than 3000 people
who have received either a single or multichannel cochlear
implant (Goldstein & Friedelwald, 1988) .
In general, it can be said that the effectiveness of
the cochlear implant is variable. Some of the variability
can be attributed to the differences among the people
receiving an implant, i.e., differences in audiological,
medical, psychological, social, and communication histories,
as well as the type of device implanted. Performance with
an implant can range from the individual who can only
distinguish between environmental sounds (for example, car
traffic versus a doorbell) to a person who is able to engage
in normal conversational discourse without visual cues
(about 5 percent) (Lansing, 1988). The most commonly
reported benefit to the cochlear implant recipient,

4
regardless of type of device, is an improvement in
speechreading ability (Lansing, 1988).
The speech perception of cochlear implant recipients
who use single or multichannel devices has been well
documented (Bilger, 1983; Eddington, 1988; Eisenberg, et
al., 1983; Holmes, Kemker, & Merwin, 1987). There has been
less research on the speech production of these patients.
The device does seem to offer benefit in this area as
evidenced by the reported improvement in loudness control
and vocal quality that has been attributed to the user's
ability to self-monitor his/her speech productions (Chouard
et al., 1983; Eisenberg et al., 1983; Engelmann, Waterfall,
& Hough, 1981; Fourcin et al., 1983). These studies, while
commenting on the speech of their subjects, were not
designed to specifically investigate speech production.
Some post-lingual and many prelingual hearing-impaired have
significant problems communicating due to their poor speech.
Cowie and Douglas-Cowie (1982) reported that one of their
subjects carried a letter explaining to people that his
slurred speech was due to his deafness and not to his being
drunk. To better address the issue of speech production of
cochlear implant users, more research is needed. The focus
of this research project was to examine the effect of
delayed auditory feedback (DAF) on the speech production of
post-lingually deafened cochlear implant users in an effort
\

5
to obtain objective evidence of their use of their "new"
auditory information to monitor their speech production.
Delayed auditory feedback (DAF) refers to an
experimentally induced time delay in a speaker's hearing of
his/her voice. Normally, the individual hears his/her
spoken utterances within approximately one millisecond
(Yates, 1963). Under DAF conditions, as an individual
speaks into a microphone, the DAF device is set to introduce
a delay in the transmission of his/her speech. The effects
of DAF on the speech of normal-hearing individuals were
noted over 30 years ago (Black, 1951; Fairbanks, 1954, 1955;
Fairbanks & Guttman, 1958; Lee, 1950). Some of the effects
included omissions, substitutions, and repetitions of sounds
as well as changes in vocal intensity. The effects of DAF
on the speech production of hearing-impaired children using
conventional amplification were studied by Maxon, Brackett,
Riordan and Pfeffer, (1987). They reported that their
subjects experienced some of the same DAF effects on speech
production that had been noted for normal-hearing subjects,
including an increase in the amount of time needed to read a
passage and to recite rote numbers, and an increase in vocal
intensity. They concluded that their subjects were making
use of some minimal auditory cues, suggesting some degree of
auditory monitoring.
The purpose of this study was to determine if DAF
affects the speech production of adult cochlear implant

6
users. A demonstrated DAF effect would seem to suggest that
the cochlear implant user was making use of auditory cues,
as did the hearing-impaired children discussed in the Maxon
et al. (1987) study. Specifically, for a population of
eight post-lingually deafened cochlear implant subjects, the
research questions to be formulated were:
(1) Is there a difference between the SAF and DAF
conditions in the duration of reading and counting
by cochlear implant users?
(2) Is there a difference between the SAF and DAF
conditions in the total number of consonant and
vowel errors made by cochlear implant users during
reading and counting tasks?
(3) Is there a difference between the SAF and DAF
conditions in the duration of reading and counting
by cochlear implant users when wearing a hearing
aid alone?
(4) Is there a difference between the SAF and DAF
conditions in the total number of consonant and
vowel errors by cochlear implant users when
wearing a hearing aid alone and performing reading
and counting tasks?

CHAPTER II
REVIEW OF THE LITERATURE
There are many different forms of communication;
however, the one which is unique to humans is speech.
Speech communication can be described using a feedback model
in which there is a sender (the speaker), a message, and a
receiver (the listener). The feedback is a combination of
auditory, visual, tactile, and kinesthetic experiences.
When there is a disruption in the auditory feedback portion,
as in the case of profound hearing loss, meaningful speech
perception is terminated and speech production may be
affected (Zimmermann & Rettaliata, 1981; Cowie, Douglas-
Cowie & Kerr, 1982; Plant, 1984). In order to re-establish
the auditory feedback mechanism, devices have been developed
which directly stimulate the auditory nerve. These devices
are called cochlear implants. The additional auditory
information provided by the implant enables some users to
understand speech auditorily (Berliner, Tonokawa, Dye, &
House, 1989; Holmes, Kemker, & Merwin, 1987; Tye-Murray &
Tyler, 1989) and also enhances speechreading ability
(Ballantyne, 1985). In addition, researchers have reported
improvements in the speech production and voice
characteristics of some implant users (Kirk and Edgerton,
7

8
1983; Leder, Spitzer, Kirchner, Flevaris-Phillips, Milner,
Rilchardson, 1986).
The purpose of this study is to examine the re¬
established feedback system in cochlear implant users by
investigating the effects of delayed auditory feedback on
the speech production of cochlear implant users with post-
lingual deafness. This chapter will review normal hearing,
speech production and perception, the effects of delayed
auditory feedback on normal-hearing and hearing-impaired
individuals (using conventional amplification), and speech
perception and production in cochlear implant users.
Hearing
The ear has been described as having several functions
to enable us to interpret sounds. The outer ear offers
protection and gives some enhancement to the sound stimulus.
The middle ear acts as an impedance matching network thereby
restoring acoustical energy that would otherwise be lost as
the sound passes through to the inner ear or cochlea. The
cochlea once was thought of as a very sensitive microphone;
however, it is now understood that it is a series of filters
which pass signals at one frequency and rejects signals at
other frequencies. This filtering ability results in the
ear analyzing complex sounds, such as speech, into its
component frequencies (Evans, 1983).

9
Normal Speech Production and Perception
Verbal communication is a complex series of acts
dependent upon the speaker producing a string of contrasting
sounds which, when heard by the listener, can be decoded and
the message understood. This process usually takes place
with ease due to the person's knowledge of the language
system and the anatomy and physiology of the speech and
hearing structures. Because of these unique structures,
human beings have the capacity to learn to produce, and
recognize, many different sounds. In the English language
there are about forty phonemes, i.e., classes of sounds that
differentiate one sound from another (Ling & Ling, 1978;
Mackay, 1987). Speech sounds are divided into two large
groups, vowels and consonants. depending upon how they are
produced and their acoustical characteristics.
In addition to the ability to produce and understand
these speech sounds, the normal-hearing listener is able to
differentiate whether the speaker is a male, female, or a
child. This ability is the result of the vocal folds
vibrating at different frequencies depending on the sex and
age of the speaker. This vocal fold vibration is referred
to as the fundamental frequency (FO). The fundamental
frequency for adult males typically occurs between 100 and
150 Hz, for adult females between 175 and 225 Hz, and for
young children between 270 and 330 Hz (Eguchi & Hirsh,
1969) .

10
Vowels
Vowel production results from a combination of exhaled
air passing through the vibrating vocal folds, over the
tongue, and out of the mouth. Changes in the degree to
which the jaw is open, the position of the lips, and the
shape and position of the tongue influence the acoustical
properties of the produced sounds yielding a distinct set of
fourteen sounds which comprise English vowels (Dew & Jensen,
1979). The shape and position of the tongue exert the
greatest influence in differentiating the different vowels.
Vowel perception is the result of changes in the
resonating cavities of the vocal tract creating different
patterns of concentrated acoustical energy which occur at
different frequencies. These patterns of concentrated
energy are called formants and are numbered from the lowest
to the highest in frequency. Although the vowel will sound
most natural if the first three formants are heard, it is
the first two formants which are critical in differentiating
one vowel from another (MacKay, 1987). Each vowel has its
own characteristic formant pattern and each individual
his/her own characteristic size and shaped vocal tract. The
result is that two different speakers will pronounce the
same vowel somewhat differently. Despite these differences
it is the formant patterns which tend to remain constant,
allowing us to recognize the particular vowel whether the
speaker is an adult (male or female) or a child (MacKay,

11
1987). In order for a person to perceive those critical
first two formants they need to be able to hear in the range
of 250 to 1000 Hz for the first formant (FI) and between 600
to 3330 Hz for the second formant (F2) (Skinner, 1978).
Diphthongs are phonemes made up of two vowel sounds and
occur as phonemes which glide from one vowel position to
another. The frequency of a diphthong is determined by the
first formant values of each vowel being added together and
the second formant values being added together giving an
approximation of the frequency range for the particular
diphthong (Ling & Ling, 1978).
Consonants
Consonants are the second large class of sounds and are
produced by changing the airflow out of the mouth. The
manner in which the air flow is interrupted yields three
distinct types of consonants: (1) plosives. which result
when the airflow is completely blocked such as in the sounds
/p,t,k/; (2) fricatives. resulting from the airflow being
restricted as in the sounds /f,v,e,s,h/; or (3) nasals,
where the air flow is directed through the nose as in the
sounds /m,n,q/.
In addition to the above types, another distinctive
feature of consonant production involves "voicing." Voicing
refers to the timing of the vocal fold vibration in relation
to the releasing of the sound that is being spoken. It is

12
this feature which allows for the distinction between the
voiced plosive /b/ and its voiceless cognate /p/. During
the production of /b/, vocal fold vibration and the release
of the /b/ occur at approximately the same time (within 30
to 40 msec.)? in contrast, there is a time lag between the
vibration of the vocal folds and the release of the /p/
(greater than 30 to 40 msec.) making it a "voiceless" speech
sound (Dew & Jensen, 1977). Lisker and Abramson (1964)
coined the term "voice onset time (VOT)" to describe the
relative timing of the consonant release and the onset of
voicing. Voicing perception is dependent on low frequency
information, usually in the range of 80 to 350 Hz for adult
speakers and at higher frequencies for children (Stevens,
1983).
The range of hearing necessary for consonant perception
varies with the different manner of production and also
within a particular class of consonants. Plosives can be
either voiced (/b, d, g/) or voiceless (/p, t, k/). The
plosives /b,p/ are relatively low frequency sounds having
the majority of their concentrated energy between 800 and
1500 Hz. The greatest energy for /d,t/ is found between
4000 and 5000 Hz, and the energy concentration for /k/
varies from 1000 to 4000 Hz depending on the frequency of
the second formant of the vowel adjacent to /k/ (Skinner,
1978). Fricatives are also in voiced-voiceless pairs and
their areas of concentrated energy vary also. The energy

13
range for the /s,z/ pair is approximately 3500 to
8000 Hz and the /J,3/ pair around 2500 to 4500 Hz. Another
acoustic cue to differentiating fricative sounds is
intensity and duration. The /v,f,h,e/3/ are less
intense and of shorter duration than the /s,z, J, 3/ phonemes
(Skinner, 1978).
Nasal sounds are produced by the sound being emitted
from the nose rather than the mouth. They are all voiced
and are characterized by a low frequency nasal "murmur" in
the range of 250 to 300 Hz.
In addition to plosives, fricatives, and nasals there
are other consonant sounds which resemble vowels and are
called glides (/w,j/) and semivowels (/r, 1/). Glides are
characterized by changing formants and semivowels by a
formant configuration similar to vowels but more restricted
in its total frequency region (Skinner, 1978).
Finally, the consonant equivalent to the diphthong is
the affricate. The affricate is a combination of a voiced
plosive combined with a voiced fricative (/d^/) or the
voiceless plosive combined with the voiceless fricative
(/tsi).
Effect of Hearing Loss on Speech Production and Perception
To be able to understand speech, especially under less
than optimal conditions, we are dependent upon our inner

14
their frequency components. Cochlear or inner-ear hearing
loss compromises that filtering system resulting in the
listener receiving a distorted signal, if any at all.
Depending on the severity of the hearing loss the signal may
not be recognized, or heard, by the listener. Since the
subjects in this study are post-lingually deafened adults,
this discussion will focus on the research reported on their
speech production and perception.
Speech production and perception studies of the
prelingual population, and suggestions for remediation, are
well documented (Calvert & Silverman, 1983; Gold, 1980;
Hudgins & Numbers, 1942; Levitt & Stromberg, 1983; Levitt,
McGarr, & Geffner, 1987; Monsen, 1983). There is less
research available on the effects of acquired hearing loss
in the post-lingual deaf population and, according to
Seyfried et al. (1989), much that is reported is generally
anecdotal. There is great variability in the speech
production of the post-lingually deaf population. This
variability has been reflected in the literature, including
the view that adventitious deafness does not necessarily
result in disordered speech (Goehl & Kaufman, 1984).
Zimmermann and Rettaliata (1981) compared the
articulatory patterns of an adventitiously deafened adult's
speech to that of a normal hearing speaker. The deaf
subject was a 34-year-old male who initially exhibited a
high frequency, sensorineural hearing loss which progressed

15
to include the low frequencies. The hearing loss reportedly
occurred between early and late adolescence and was of
unknown origin. The subject's hearing loss stabilized
around age 26 and he referred himself to a university speech
and hearing clinic at the age of 27 because of concern about
his speech. At that time audiometric test results indicated
that he had a profound sensorineural hearing loss; however,
an informal assessment of his speech led to the conclusion
that speech therapy was not needed. At the age of 32 the
subject again sought an evaluation of his speech and voice
production. Although his speech exhibited some deviations,
the overall interpretation of the results was that there
were "no perceptual phonemic findings during the speech
tasks" (p. 170). At the time of this study, an informal
assessment of the subject's speech by two trained listeners
judged all of the subject's utterances to be phonemically
accurate. The speech task for the subject was to say [bib],
[bab], [si], [bar], [rab] in the carrier phrase, "That's a
..." (p. 170).
Articulatory patterns of the subject were recorded
using high speed cinefluorography and compared with the
normal hearing control. The speech productions of the deaf
subject revealed systematic timing differences in the
closing portion of each utterance, deviations in

16
coordination of the tongue dorsum with other structures, and
consistently late voice termination compared with the normal
control.
The authors suggested that speech in a deaf individual
is acquired slowly because of overlearned motor patterns.
Exceeding normal variability ranges of these patterns must
occur repeatedly, without the speaker realizing the error,
for degeneration in speech patterns to occur. They
concluded that auditory information "plays a critical role
in the long term monitoring and maintenance of coordinative
structures (mainly involving the tongue dorsum musculature)
for speech" (p. 177).
Cowie et al. (1982) studied twelve post-lingually
deafened adults in Northern Ireland. All of their subjects
were classified as having profound, bilateral sensorineural
hearing loss, with the exception of one subject who had some
hearing in one ear but was losing it. The purposes of their
study were to: (1) analyze articulation errors, (2) provide
useful measurements of the subject's intelligibility, and
(3) identify problems, other than intelligibility, that the
subjects reported.
Tape recordings of the hearing-impaired subjects
reading five short passages and conversing, singly or in
groups, with a normal interviewer were made. Recordings
were also made of one normal hearing subject under the above
conditions. Ten normal hearing subjects were assigned to

17
listen to each hearing-impaired subject's recording. Speech
intelligibility was measured using a "shadow technique."
This technique involved the normal hearing subjects
listening to the taped recordings and attempting to repeat,
verbatim, what was said as it was being said. The
percentage of correctly repeated words was the measure of
intelligibility. The authors listed the following caveat
regarding the level of information provided by this
technique: (1) it is a relative measure of intelligibility;
(2) the results do not identify cut-off points between
subjects with intelligibility problems and those with normal
hearing; and (3) measurements using this technique are not
directly comparable to studies of the pre-lingually deaf.
Despite the above limitations, the results obtained did
suggest two points: (1) most of the subjects had measurable
losses in intelligibility; and (2) there was variability
among the subjects. General factors affecting all subjects
pertained to: (1) style and content of the reading passage
in which the simpler the style, and more familiar the topic,
the higher the intelligibility scores; and (2) age at onset
of deafness seemed to have the greatest effect on
intelligibility with the two worse speakers becoming deaf
before 10 years of age and the two best speakers becoming
deaf after 18. However, the authors caution that a larger
sample is needed before generalizations about this finding

18
can be made. The authors also noted that their data did not
suggest that factors such as social background, intelligence
or motivation were relevant.
Other problems related to speech deterioration were
explored in this study by evaluating normal-hearing
listener's responses to the speech of eight of the original
twelve deaf subjects. All subjects listening to the deaf
speakers reported that they would have problems
understanding their speech. All but one of the listeners
reported that they would keep the conversation with the deaf
speaker as brief as possible. In addition these findings
illustrated the tendency of people to associate
characteristics of speech with characteristics of speakers.
For example, a speaker with a harsh vocal quality was viewed
as "unfriendly" (p. 108). The authors concluded that these
findings suggest that post-lingually deaf individuals
experience some degree of speech deterioration but there is
wide variability in this population, and age at onset of
deafness appeared to be a relevant factor in the level of
deterioration. The significant speech deterioration in many
of the subjects illustrated the need for more attention to
speech conservation in this population, to enable them to
function in the hearing world.
Plant (1984) reported case study findings of a male
subject deafened by meningitis at age 11 years. The
subject's speech production was evaluated in the following

19
areas: (1) phonetic errors in spontaneous and read speech;
(2) intelligibility errors using monosyllabic words; and (3)
ratings by normal-hearing listeners of the subject's speech
production at 2 months and 30 months following the onset of
deafness.
Analysis of phonetic transcriptions revealed omissions
to be the most prominent error; specifically the phonemes
/d/ and /t/. Some of these instances were attributed to
normal colloguial usage such as the word "and" being
shortened to "an." Of 69 omissions, 64 were for the
alveolars /t, d, s, z/. The author suggested that audition
may be very important in maintenance of these sounds due to
their weak tactile cues.
Vowel quality findings differed from the read to
spontaneous speech samples with the spontaneous sample
yielding more instances of schwa that in normal hearing
readers. This was attributed to the subject's exaggerated
care and precision while reading "leading to a highly
artificial sample" (p. 40).
The suprasegmental features of speech were found to
show deviations from the norm also. The deviations noted
were: (1) inability to control pitch; (2) production of all
syllables with equal stress; and (3) slower than normal rate
of speaking.
Recordings of the subject's production of four lists of
monosyllabic words were presented to 24 normal hearing

20
listeners. The listeners gave written responses to what
they heard and these responses were recorded on confusion
matrices for initial consonants, vowels, and final
consonants. Initial consonant errors represented 7% of the
presentations and of those errors affricates were the most
commonly misunderstood (21%). Additional analysis of the
affricates revealed that the voiceless affricate (/1J*/)
accounted for 31% of the errors. In addition, of those
errors, over 75% involved substituting the consonantal blend
/tr/ for /tf/. The voiced affricate (/dg/) yielded an error
rate of 12% of the presentations and almost 50% of those
errors involved substitution of the blend /dr/ for /d^/.
The author suggested that relatively weak tactile cues for
the release phase of the affricates necessitates auditory
monitoring to maintain correct production.
Analysis of vowel and diphthong errors indicated
confusion with adjacent vowels, suggesting "overlapping" of
formant values (p.45). This was further supported by the
number of errors between vowels with similar FI values which
was explained by the fact that the F2's are more distorted
and the subject's knowledge, or memory, of tongue placement
had been adversely affected by the hearing loss. This view
was further supported by evidence that more diphthongs were

21
"perceived as steady state rather than dynamic movements"
(p. 45). Conversely, the vowels were correctly perceived as
steady state.
The greatest number of consonant errors involved place
of articulation. These findings agree with those of
Zimmermann and Rettaliata (1981) and further support the
importance of audition in the production of closing gestures
for speech. Without synchronous and correct articulatory
patterns there may be a "blurring" of place cues (Plant,
1984) .
The final area of investigation involved presenting
three spontaneous speech samples, recorded by the deaf
subject at approximately 2 months and 30 months after the
onset of deafness, to twelve normal-hearing listeners. The
listeners were asked to rate the samples on voice guality,
pitch, intonation, and rate. The recording made at the 2
month interval, post-onset, was rated near normal, whereas
the recordings at 30 months, post-onset, was rated as
abnormal. The parameters rated most deviant were pitch and
intonation.
The above research has delineated errors in speech
production which the authors attributed directly to
adventitious profound hearing loss. Goehl and Kaufman
(1984) take exception to this view by criticizing a study by
Binnie, Daniloff, and Buckingham (1982) and argue that those
authors did not take into consideration the subject's age (5

22
years 0 months) at the time hearing was lost. They
emphasized that the onset of deafness resulted in an
interruption in the maturation of the child's phonologic
system. They speculated that this inability to continue to
learn speech, auditorily, from others would account for the
speech deterioration and would be as important as loss of
auditory feedback. They further questioned the influence of
speech training techniques used with the child (these
techniques were not described) and finally the possible
continuing residual effects from the etiology of the hearing
loss (meningitis).
These authors also raise questions regarding Zimmermann
and Rettaliata's (1981) interpretation of their data. They
noted that these authors pointed out the inability to
generalize their findings due to the sample size (N = 2) and
the considerable variability in speech production across
speakers regardless of their ability to hear or not. In
addition, they questioned whether the differences between
the hearing and deaf subjects were real differences because
of the limitations of describing the utterances being judged
as "phonemically accurate" (p. 170) by the two trained
listeners, i.e., no formal clinical assessment was made of
the subjects' speech prior to their experiment.
Due to the lack of empirical data and the general
expectations by clinicians that speech deteriorates over
time in deaf patients, Goehl and Kaufman used six ASHA

23
certified speech-language pathologists as judges to
determine if there were identifiable changes in the speech
of normal hearing and deaf subjects. The specific questions
addressed in the study were whether those expert listeners
would be able to: "(1) judge articulation as within normal
limits, and (2) identify any of the speakers as being
adventitiously deafened" (p. 60).
The subjects were divided into two groups, deaf and
hearing and were matched for sex and were similar in age
(range: 60 to 79 years old). The deaf group was selected
from a pool of twelve who were attending a speechreading
group at the time of the study. Based on their audiometric
results they were expected to develop "speech deviations"
due to their degree of hearing loss (Calvert, 1982). The
control group, based on audiometric evaluation, was
determined to have normal (for age level) hearing.
Each subject was taped reading the Grandfather Passage.
The passages were randomized and the order of presentation
was reversed for every other judge. The second question
(i.e., identification of deaf speakers) was always presented
after the first (i.e., identification of normal articula¬
tion) in order to prevent listener bias. It was also done
to give the listener unlimited trials in order to make a
decision about the subjects' responses and avoid measuring
the judges' ability to do a timed task.

24
The results indicated that all of the subjects were
judged to have normal articulation, but that deafened
speakers could be identified at better than chance level.
In addition neither the number of years since the onset of
deafness nor the degree of impairment seemed related to the
listener's labeling the speaker as deaf. The authors
reported that a review of the comments of the judges
describing the speech of those subjects identified as "deaf"
included differences in rhythm, rate, voice quality, and
"slightly inaccurate articulation" particularly in regard to
sibilants (p. 63). Goehl and Kaufman suggested that these
findings may be supported by Zimmermann and Rettaliata
(1981) ; however, they also pointed out that some of the
judges in their study misidentified some normal subjects.
They also point out the possible influence of the
expectations which the judges brought to their task once
they knew that the subjects were deaf. These expectations
were described as a willingness on the part of the judges to
tolerate mild changes in speech that are associated with an
elderly population (rate, voice, articulation) and still
conclude that speech production was within normal limits.
Goehl and Kaufman concluded that clinically significant
speech production deterioration, as a result of adventitious
deafness, was not supported by their data. In addition they
stated that the view that auditory feedback is essential to

25
maintaining speech based on a servo-mechanism theory of
speech control was also not supported in their study.
Acquired hearing loss produces variable effects on the
speech of post-lingually deafened adults. The loss of
auditory monitoring capabilities has been the attributing
cause of speech deterioration in some of this population
(Cowie et al., 1982; Plant, 1984; Zimmermann & Rettaliata,
1981). A dissenting view was reported by Goehl and Kaufman
(1984). Finally, the need for more research in this area is
apparent due to the lack of conclusive empirical studies
(Seyfried et al., 1989).
Cochlear Implants
Cochlear implants are surgically implanted devices that
directly stimulate the inner ear and produce a sensation of
sound. The Ad Hoc Committee on Cochlear Implants (Hopkins,
1986) listed eleven different types of implants which are
being manufactured in the United States or Europe; however,
Gibson (1987) wrote that there are reportedly over 40
different cochlear implant devices being investigated
worldwide.
Despite the number of implants being investigated,
their basic composition remains the same: (1) microphone;
(2) speech processor; (3) transmitter coil; (4) receiver
coil; and (5) electrode(s) (Gibson, 1987).

Differences in Cochlear Implants
The differences in cochlear implants can be described
26
by examining the following features: (1) number of
electrodes; (2) electrode position; and (3) speech
processing strategy.
The earliest and simplest cochlear implant still
employed today had a single electrode ("single channel")
(House, 1976). Some examples of multi-electrode, or "multi¬
channel" implants cited by Gibson (1987) and the Ad Hoc
Committee (Hopkins, 1986) included the Symbion (4 channels) ,
Chorimac (12 channels), and Nucleus (22 channels) devices.
The configuration of the electrodes in the multichannel
devices differ, but as all subjects in this study will be
wearing the Nucleus device, a description of its electrode
configuration will be given in more detail later in the
chapter.
The second difference in cochlear implants is the
electrode positioning. An extracochlear electrode may be
placed on the membrane of the round window; this type being
investigated by Hochmair (#M/Vienna implant) and Fraser
(Finetech/RNID) as cited by Gibson (1987). Examples of
intracochlear devices include the Symbion, the Chorimac, and
the Nucleus (Gibson, 1987).
The third difference in implants is the speech
processing strategy. Many implants use an analog signal
which is bandpass filtered, for example, the #M/House signal

27
is filtered between 340 and 2700 Hz (Boothroyd, 1989). This
filtered signal is used to vary the amplitude of a 16 KHz
sinusoidal carrier signal which is set just below
audibility. There is no other processing after the
amplitude modulation. The clinician is able to adjust the
carrier level and limit the maximum output through
manipulation of the processor controls for each patient.
Limiting of the maximum output is by peak clipping. Moore
(as cited by Kessler, 1989), referred to this type of
processing as the "modulated-carrier, analog approach,
defining it as a strategy in which the waveform itself is
used to drive the electrode and in which an attempt is made
to squeeze the entire speech signal into a single channel"
(p. 188).
Another type of speech processing, and the one used by
the Nucleus device, selectively extracts components of
speech from the acoustic signal. The directional microphone
picks up sounds and sends the information to the speech
processor. The speech processor filters the sound and
extracts formant information from the speech signal. That
information passes to a "map" which is the digital memory in
the speech processor and it is here that the appropriate
electrode, current amplitude, and stimulus rate are
assigned. The signal is coded and travels through the skin
by a radio frequency signal to the implanted receiver-
stim&lator. Lastly, the receiver-stimulator decodes the

28
signal, allowing pairs of the 22 electrodes to be stimulated
to produce speech-like sounds.
The Nucleus device extracts fundamental frequency (F0);
from the speech of the person and sends that information to
the speaker by the rate of stimulation pulse. Signal
intensity information is conveyed by the amplitude of the
pulses. First (FI) and second (F2) formant information is
provided from the position of the electrodes. Initially,
the Wearable Speech Processor (WSPII) provided only FO and
F2 information. In 1985, another coding strategy (WSPIII)
providing F0F1F2 information became available (Dowell,
Seligman, Blarney & Clark, 1987). In this coding strategy a
basal electrode was stimulated followed in rapid succession
by stimulation of a more apical electrode yielding F2 and FI
cues, respectively. The addition of FI to the processing
strategy would be expected to further enhance vowel
perception as those formants are known to be critical
(MacKay, 1987). The most recent development in coding
strategy became available in 1989 with the Mini Speech
Processor (MSP) (Skinner, Holden, Dowell, Seligman,
Brimacombe, Beiter, 1991; Clark 1991). The MSP employs a
"multi-peak" strategy which measures dominant spectral peaks
for frequency ranges containing FI (270-730 Hz) and F2 (840-
2290 Hz), as well as, the energy contained in those
frequency bands. These measurements have been designated A1
and A2 and correspond to FI and F2, respectively. In

29
addition three other frequency bands can be activated A3
(2000-2800 HZ), A4 (2800-4000 Hz), and A5 (4000-7000 Hz)
(Patrick & Clark, 1991). A1 and A2 are always activated and
activation of the higher frequency bands is dependent upon
the particular acoustic signal being sampled. In the case
of unvoiced stimuli there is a small amount of energy in the
FI frequency range so the electrode for FI is not
stimulated. In its place the fixed electrode for the A5
band is activated thereby extracting high frequency
information (Clark, 1991). The opposite is true for voiced
stimuli. Since there is only a small amount of high
frequency energy in voiced stimuli the A5 electrode (4000-
7000 Hz) is not activated. The ability of the speech
processor to provide the frequency bands A3, A4, A5 in
combination with F0F1F2 information provides more vowel and
consonant information.
In addition to extracting information important for
understanding speech. The electrode configuration is
designed to take advantage of the physiological response of
the cochlea. This is accomplished by stimulating discrete
areas of the basilar membrane. The configuration is
described as '•bipolar." Bipolar electrodes are small and
are located at equal distances from the target nerve and
stimulate discrete areas of the cochlea. In contrast,
monopolar electrodes are larger and the active electrode is
closer to the nerve than the ground electrode. Monopolar

30
electrodes stimulate large groups of nerve cells and are not
effective in providing discrete areas of stimulation
(Fravel, 1986). The design of the Nucleus implant, using
the bipolar electrode configuration, takes advantage of the
place pitch theory of hearing. For example, stimulation of
the high frequencies necessary for F2 perception can be
accomplished because of the number of electrodes and the
fact that high frequency information is coded on the basis
of place on the basilar membrane. In contrast, the low
frequency information found in F0 is used to stimulate each
electrode at a rate proportional to the voicing frequency
(Clark, 1986). This is consistent with what is known about
low frequency hearing which is coded based on the "place of
maximal, discharge and the periodicity of the discharge
pattern...." (Yost, 1985, p. 92-93).
Patient Selection Criteria
There has been a wide range in selection criteria and
large variations in patients' responses as more people have
received the devices. At the present time there are no
standardized criteria for accepting or rejecting a cochlear
implant candidate (Goldstein & Friedelwald, 1988). Maddox
and Porter (1983) have suggested that rather than asking,
"Who is a candidate for a cochlear implant?" it would be
better to ask, "Who is not a candidate for a cochlear
implant?" They further stated that, in their opinion, each
potential candidate must be evaluated "on an individual case

basis and should not be generalized to the profoundly
deafened population as a whole" (p. 250).
The criteria suggested by the National Institutes of
Health Consensus Development Conference Statement (1988)
include the following:
(1) Audiological Criteria:
(A) Bilateral, profound sensorineural hearing
loss
(B) Bilateral, aided thresholds greater than 60
dB HL
(C) 0 percent correct on open-set speech
recognition
(D) Lack of substantial increase in lipreading
with appropriate amplification
(2) Electrophvsiological Criteria:
(A) Measurement of early, middle, and late
latency evoked potentials
(B) Absence of neural responses may or may not
prove to be a contraindication
(3) Medical Surgical Criteria:
(A) Usual candidate is a postlingual onset,
healthy adult
(B) Possible complicating factors include:
(i) Anatomical problems which may preclude
insertion of the electrode(s)
(ii) Pre-existing ear problems

32
(4) Psychophysical Criteria:
(A) None of the psychophysical data available,
for example gap detection, are considered
critical to the issue of candidacy at this
time
(B) Psychophysical data have not been shown to be
good predictors of speech recognition
performance
(5) Psychological and Linguistic Criteria;
(A) Most psychological testing is done for
exclusionary purposes such as mental
retardation or psychiatric disorders
(p. 2)
Risks and Benefits of Cochlear Implants
As with any surgical procedure and use of general
anesthesia, there are inherent risks to the patient. The
risks cited by the Ad Hoc Committee Report (Hopkins, 1986)
include:
(1) The reduction or total loss on any presurgical
residual hearing
(2) Complications due to anesthesia and surgery
(3) Post-surgical risks:
(A) Bioincompatibility of the internal components
(B) Extracochlear infections
(C) Intracochlear infections secondary to otitis
media

33
(D) Facial nerve damage/paralysis
(E) New bone growth within the cochlea
(F) Intracochlear scarring and fibrous tissue
growth
(G) Degeneration of surviving nerve fibers
(H) Unknown reactions to prolonged electrical
stimulation
(I) Required replacement of failed internal
components
(4) Unrealistic expectations of cochlear implant
patients and family leading to psychological
disturbances
(5) Possible vestibular complications
(6) Possible exacerbation of tinnitus
Possible benefits cited by the committee include:
(1) Increased awareness of sound
(2) improved ability to monitor speech production
(3) Recognition of some everyday sounds
(4) Improved awareness of surprasegmental features of
speech
(5) Supplement to lipreading
(6) Perception of some segmental aspects of speech
leading to limited word recognition and
understanding of speech
(7) Reduction of tinnitus

34
(8) improved social interaction and employment
potential
(9) Significant word recognition in sentences in
sound-alone conditions
(p. 45)
Aural Rehabilitation Issues
Aural rehabilitation of the cochlear implant patient
begins with the evaluation procedures employed during the
selection process. Lansing (1988) has divided the
rehabilitation process into three areas: (1) development of
realistic expectations for the implant; (2) training in the
interpretation and use of the new auditory information with
and without visual cues; and (3) development of coping
strategies to enhance communication. Some of the
variability of responses from patients, no doubt, is due to
their individual differences; however, some may be due to
the differences in protocol among the centers. While most
centers offer counseling, ongoing adjustment of the device,
direct training and measures of performance, others only
provide counseling and adjustment to the implant (Hopkins,
1986). Others, like the House Ear Institute and the centers
implanting Nucleus devices have specified extensive
protocols for adjusting the implant and training the
patients to use the device. The question of degree of
effectiveness of the implant versus effectiveness of the
training remains an issue in need of further study.

35
Speech Perception Studies of Cochlear Implant Users
Speech perception studies with the implant, including
both single and multi-channel have been an area of wide
interest to the research community (Bilger, 1983; Eddington,
1988; Eisenberg, et al., 1983; Holmes, Kemker, & Merwin,
1987) . The perception of speech using auditory cues only
has been seen in some patients and has recently been
reported for some children. Berliner, Tonokawa, Dye, &
House (1989) evaluated 50 profoundly hearing-impaired
children over the age of 5 years. All the children were
implanted with the 3M/House single-channel device. Their
ages at the time of the study ranged from 5.2 to 15.9 years,
with average age at the onset of deafness of 2.0 years. Age
at the time of receiving the implant ranged from 2.4 to 15.3
years, with a mean of 6.2 years. Test materials were
administered using live-voice at a normal conversation
level. Portions of the Glendonald Auditory Screening
Procedure (GASP) (Erber, 1982) were administered to assess
open-set speech recognition. The authors noted that the
GASP is designed as a closed-set test (i.e., picture
pointing task; however, for this study it was administered
auditorily only. The children were tested with word and
sentence stimuli using an auditory mode only. They reported
that 52 percent of the children demonstrated some open-set
discrimination on the word identification. Sentence
comprehension scores were 41.5 percent. The duration of

36
deafness was noted to be shorter for children able to score
on the open-set discrimination task than for those who were
unable to do so. Berliner, et al. (1989) also cited a study
by Geers and Moog (in press) in which they assessed 7 of 12
high-performing children using the 3M/House device, they
also reported that of the 12 children in the study 7
achieved some open-set, auditory-only recognition of simple
sentences.
Dorman et al. (1989) investigated the ability of
patients using the Symbion multi-channel implant to identify
synthetic vowels. Eight subjects participated in the study,
all at least 18 years old. The length of deafness ranged
from 1 year to 28 years with a mean of 6.6 years. The
results of this study indicated that all eight subjects
scored above 70 percent correct on a test of spondee word
identification. Twelve synthetic vowels in the "bvt" format
comprised the stimuli. Vowels characterized by low FI and
F2 formants were well identified whereas those with high FI
and low F2 formants were not well identified. The authors
concluded that their results were consistent with the model
of FI being specified by a rate code and extreme values of
F2 specified by a rate/place code.
Waltzman and Hochberg (1990) investigated the
perception of speech pattern contrasts in patients using the
Nucleus device in either an F0/F2 coding strategy (N = 9) or
an F0/F1/F2 (N = 7) strategy. Subjects in this study ranged

37
in age from 26 to 85, with a mean age of 51 years. The
Speech Pattern Contrast (SPAC) test (Boothroyd, 1987) was
used to evaluate the perception of speech pattern contrasts
by the subjects. This test evaluates the perception of four
suprasegmental and eight segmental speech contrasts. It is
a forced-choice format using real words, phrases, and
sentences. The results of this investigation indicated that
both processing strategies provided sufficient information
about speech contrasts; especially, fundamental frequency,
temporal, and intensity cues.
Lastly, Tye-Murray and Tyler (1989) investigated
auditory consonant and word recognition skills of 22
subjects; two wore 3M/House implants, three wore 3M/Vienna
implants, seven wore Nucleus implants, and 10 wore Symbion
implants. The speech materials consisted of 14 consonants
in an /iCi/ context and the Sentence Test Without Version 1
(Tyler, Lansing, & Preece, 1984). Their conclusions were as
follows:
(1) Most subjects recognized consonants in an
audition-only condition at above chance level.
(2) Subjects perceive the envelope feature relatively
well and the place feature relatively poorly.
(3) The voicing, nasality, duration, and envelope
feature were better utilized for consonant
recognition by subjects wearing the Symbion device
than subjects wearing the Nucleus (F0/F2) device.

38
(4) Most multi-channel users achieved some open-set
word recognition in an auditron-only mode, and
there was wide range of performance. None of the
3M/House or 3M/Vienna users achieve any open-set
word recognition.
(5) Subjects who are able to utilize middle and high
frequency information are more likely to score
better on open-set sentence tests.
Speech Production in Cochlear Implant Patients
The speech production of cochlear implant patients has
not been investigated as thoroughly as speech perception.
As stated in the introduction, the device seems to offer
benefit as evidenced by the reported improvement in loudness
control and vocal quality. Those improvements have been
attributed to the re-establishment of the auditory feedback
channel (Chouard, et al., 1983; Engelmann et al., 1981;
Fourcin et al., 1983).
One study designed specifically to investigate the
effect of the single channel cochlear implant on voice
parameters was reported by Kirk and Edgerton (1983). The
subjects were two men and two women, ages 56 to 65 years.
Speech samples of the subjects reading the Rainbow Passage
with the implant off and on were obtained from the users and
normal-hearing control subjects. The results indicated that
males had a tendency to speak with lower FO when the implant
was on, and with reduced variability of vooal intensity.

39
These changes were in the direction of the normal-hearing
controls. The female subjects produced voices that were
higher in FO than when the implant was turned off. Again,
this finding was in the direction of the normal-hearing
control speakers. All of the subjects continued to
demonstrate prolongation of sentences and pauses consistent
with the speech of the deaf even when the implant turned on.
In conclusion, the authors cited the need for further study
in this area.
Speech production output of three, post-lingual,
Nucleus, 22-channel implant users was reported by Medwetsky,
Hanin, and Boothroyd (1987). Their subjects had been judged
as successful implant users based on their speech
recognition ability, with only the implant, and their
excellent sentence perception using the implant with
lipreading. Their subjects had become deaf at the ages of
5, 18, and 38 years, respectively. They had received their
implants at ages 27, 38, and 23 respectively. The purpose
of the study was to evaluate their pre- and post-implant
speech production as defined by intelligibility.
Boothroyd's Speech Perception Contrast (SPAC) test was
used to measure the intelligibility of phonetic contrasts.
While the test was originally designed to measure speech
perception the authors noted that Boothroyd has also shown
this test to be equally effective in assessing speech
production. The test material was recorded by each of the

40
three subjects twice. A pre-implant recording was initially
made and 3-4 months after implantation a second recording
was obtained. The subjects did not receive any speech
therapy during the interval between receiving the implant
and making the second recording. Twelve normal-hearing
listeners were presented the recordings of each implant user
and they gave written responses to what they heard. The
results obtained indicated that there were significant
improvements in the production of Speech Pattern Contrasts
for all three subjects. These improvements were mostly in
voicing, stress, and intonation. It was suggested that
these improvements were due to the auditory feedback
provided by the implant. Two of the subjects also
demonstrated significant improvement in phoneme and word
production.
Oster (1988) reported changes in the speech production
of ten post-lingual Swedish patients who received the
3M/Vienna extracochlear single-channel device. The research
was conducted after 18-24 months of implant use. The
patients had varying causes of hearing loss and their ages
ranged from 25-55 years old. Recordings were made of the
subjects' reading a "standard passage of 92 words" (p. 15).
The subjects read prior to receiving the implant and at one,
three, six, twelve, eighteen months post-implant. Five of
them made another recording at twenty-four months. The
results indicated that most of the subjects were within

41
normal limits for appropriate pitch prior to receiving the
implant. However, any changes noted post-implant were
reportedly towards the normal ranges. This was interpreted
as evidence that subjects are able to make use of low
frequency information received through auditory feedback in
order to control and monitor their pitch. Those subjects
whose pre-implant voices had been described as tense or
harsh were reported to exhibit improved voice quality
following implantation. Subjects and relatives responded to
a subjective questionnaire to assess the perceived benefit
of the implant. All of the subjects reported feeling more
confident in their communication following receiving their
implant. Lastly, DAF was used at durations of 200-600
milliseconds to attempt to determine the feedback provided
with the implant. Responses reported in the literature for
normal-hearing individuals (i.e., slow speech, repetitions
or words or syllables, higher intensity, and an increase in
pitch") were not found in these subjects. Two explanations
were offered for this lack of response: (1) years of total
deafness had resulted in patients learning to rely on
tactile feedback, and (2) FO and durational auditory cues
are perceived as background noise and do not influence
articulation.
Delayed Auditory Feedback
Delayed auditory feedback (DAF) is a condition in which
there is an experimentally induced time delay in a speaker

42
hearing their own voice. Normally, as people speak, they
hear their own voices within approximately one millisecond
(Yates, 1963). Lee (1950) first described a condition of
DAF which produced changes in the speech production of some
individuals. He reported that his subjects read a
"moderately difficult text at a comfortable speed...."
While under different conditions of DAF. The changes he
noted in their speech included a slower rate and stuttering
characterized by repetition syllables or fricatives. He
suggested a model of speech production to explain this
finding by describing a closed-loop system in which the
length of each loop was approximately proportional to the
time necessary for its particular function. He defined four
loops, arranged in a hierarchy, made up of: (1) an
articulatory loop (phonemes), (2) a voice loop (syllables),
(3) a word look, and (4) a thought loop. He proposed that
the auditory system was in series with the voice loop for
auditory monitoring and that the articulatory and voice
loops were most affected by DAF. Lee stressed that any loop
of the model, down to the syllable level, may be repeated if
the auditory monitor is dissatisfied with the previous
performance. Further, there was a common junction for all
of the loops which was represented by a cortical speech
center. He concluded that speech production changes under
DAF were due to a dysfunction of this closed-loop system at
the phonemic (articulatory) and/or syllable (voice) level.

43
Fairbanks (1954) proposed a more elaborate closed-loop
model, or servosystem, of speech production based on
auditory monitoring and illustrated his model with studies'-
utilizing DAF. His model included a "sensor unit" which fed
auditory, tactile, and proprioceptive information back to
the "comparator unit." This information was compared to the
output and the comparator identified any discrepancies
between the two signals. He noted that the delayed auditory
feedback condition "misinforms" the system about its success
in effecting and in ordering its intended output units, thus
impairing its basic produce" (p. 334).
In 1955, Fairbanks reported on the articulation errors
and changes in the rate of speech of his subjects under the
DAF condition. Subjects for this study were sixteen male
college students who had never experienced DAF. They read
the Rainbow Passage under five different stimulus conditions
with the speech output amplified by a constant amount and
the delay intervals varied from 0 to 800 milliseconds.
Results indicated that DAF resulted in a variety of speech
disturbances divided into two groups: "direct effects" and
"indirect effects." Direct effects included an increase in
articulatory errors and longer duration and indirect effects
included an increase in sound pressure, i.e., increased
speech intensity, and a higher fundamental frequency. A
subsequent study by Fairbanks and Guttman (1958)
investigated further the effects of DAF on articulation.

44
The data were from the subjects in the 1955 study of sixteen
male college students and the various types of errors found
in the original study were investigated. Their analysis
indicated that there was agreement with the original study,
i.e., the general effect of DAF led to a reduction in the
number of correct words read and an increase in the total
time for the reading. They also noted that the maximum DAF
effect was seen using a 200 millisecond delay. The
articulatory errors reported included substitutions,
omissions, and additions. The greatest number of errors
were in additions and about 70% of those were repetitive.
The authors noted that the repetitions were not primarily
corrective but rather a purposeless response.
The amount of delay which is most disruptive has been
shown to vary as a function of age with the delay necessary
to disrupt speech decreasing with age (MacKay, 1968; Siegel,
Fenst, Garber, & Pick, 1980). Many researchers (Black,
1951; Fairbanks, 1955; MacKay, 1968; Buxton, 1969;
Harrington, 1988) have reported that between 180 and 200
milliseconds produces the most disruption to the speech of
adults, with the exception of older adults (60 to 81 years
old) who experience maximal disruption of their speech at
400 milliseconds (Buxton, 1969).
Differences related to gender are not as clear as those
reported for age. Some researchers have found differences
with males more often affected than females (Timmons, 1971;

45
Timmons & Boudreau, 1972), however, Buxton (1969) reported
no differences.
The demonstrated DAF effect has been interpreted by
many researchers as evidence that speech acts as a
servomechanism and auditory feedback is the primary control
channel (Borden & Harris, 1984). However, Borden and Harris
(1984) also noted that this view has been challenged by
those who point out that the DAF effect can, for example, be
overridden if the speaker attends to the reading and ignores
the acoustic information being received. In addition,
measures other than DAF will interfere with speech
production, for example, amplifying the air conducted sound
will cause speakers to decrease their vocal intensity
(Siegel & Pick, 1974), attenuating the air conducted sound
will produce the opposite effect and if listeners are unable
to hear their speech at all they will increase their vocal
intensity and prolong voicing (Lane & Tranel, 1971).
Finally, Borden and Harris (1984) suggested that audition as
a feedback mechanism for monitoring ongoing fluent speech
production does not provide a complete explanation "because
for many transient sounds it provides information to the
speaker too late; he has already spoken and can only make
corrections after the fact" (p. 136). However, there was
agreement that speakers do use audition "to sharpen their
speech sound targets" and that when there is interference

46
with auditory feedback they will try to overcome it by
attempting to correct their speech output.
Harrington (1988) offered another model to explain the
DAF effect by including the influence of rhythmic structure
in the production of fluent speech. He noted that the
literature addressing the acoustic and articulatory aspects
of coarticulation suggested that consonants and vowels are
produced using "separate articulatory strategies that
overlap in time." He stated that rhythmic structure
"prespecifies the intervals between vowels of stressed
syllables" and that same structure allows the speaker to
predict when vowels of stressed syllables will be auditorily
perceived. He illustrated his model by describing the
production of two syllables, SI and S2, by a fluent speaker
under DAF. The time of production of the vowel of S2 would
be some arbitrary unit of time after the vowel of SI and the
amount of DAF was 180 milliseconds. He suggested that the
DAF effect produces a mismatch between the "actual time of
production of the vowel of S2 and the expected time of
perception" (p. 39). The speaker's attempt to correct the
mismatch results in the onset of dysfluent speech.
In an effort to study auditory reliance, Maxon,
Brackett, Riordan, and Pfeffer (1987) studied the effect of
DAF on hearing-impaired children. Data were obtained on 19
children, all of who had a mean length of utterance of at
least 3.0. All of their subjects were enrolled in

47
oral/aural educational programs. The authors reported that
their subjects displayed disturbances in their speech
production under DAF which were similar to those reported in
the literature for normal hearing individuals, i.e., an
increase in the time to read the passage or reciting note
numbers and an increase in vocal intensity. Based on their
results they interpreted the data to suggest that hearing-
impaired children can make use of minimal auditory cues
during self-monitoring.
A review of the DAF literature indicates that while
there may be various explanations to explain the effect, the
presence of an effect is not disputed. The literature also
suggests that audition influences an individual's fluent
speech production.
Summary
The importance of auditory feedback to the normal
acquisition of speech and language is unquestioned.
However, there are differing views as to its degree of
importance in maintenance of normal speech production for
the adventitiously profoundly hearing-impaired (Cowie &
Douglas-Cowie, 1983; Goehl & Kaufman, 1984; Zimmerman &
Rettaliata, 1981). Many of this population experience
significant changes in speech production. These changes
occur over time and can range from mild to severe in
affecting the person's intelligibility. Many of this same
population do not receive benefit from conventional

48
amplification. A cochlear implant is the only type of
device available which has the capability of providing
auditory feedback to them. Some studies of speech
perception in cochlear implant users have reported
improvement in loudness control and voice quality and have
attributed the improvement to the reestablished auditory
feedback (Chouard, et al., 1923; Engelmann et al., 1981;
Fourcin et al., 1983). The area of speech production in the
adventitiously deafened cochlear implant user has not been
extensively studied. It is an area needing further study to
document the effectiveness of the reestablished auditory
feedback system and to begin to evaluate its effectiveness.
Delayed auditory feedback offers a tool for making objective
measures of the cochlear implant users speech production
with and without the implant.

CHAPTER III
METHODOLOGY
The procedures in this study were designed to ascertain
whether there is a delayed auditory feedback (DAF) effect on
the speech production of post-lingual cochlear implant
users. Specifically, the parameters measured for evidence
of a DAF effect were: (a) reading rate as measured in total
time to read the Grandfather Passage, (b) speech duration as
measured in total time to count backwards from 100 to 70,
and (c3) total number of consonant and vowel errors in
reading and counting backwards. The cochlear implant users'
speech was recorded in the presence and absence of DAF with
their cochlear implant speech processor off and on. In
addition, a third experimental condition was investigated
using conventional amplification in the unimplanted ear.
Subjects
Eight subjects participated in this study—five women
and three men. All had completed the recommended number of
post-implant aural rehabilitation sessions and all were
wearing the Melbourne (Cochlear Corporation) 22 multichannel
electrode array (Nucleus) implant at the time of the study.
There was no selection based on gender and/or race. The
49

50
subjects ranged in age from 31 to 61 years with a mean of 47
years. Reported hearing loss etiologies included
meningitis, noise, Meninere's Syndrome and four with no
known etiology. One of these unknown etiologies was
suspected to be Cogan's Syndrome. Unaided pure tone
averages (500, 1000. 2000 Hz) in the better ear ranged from
75 to 115+ dB HL with a mean of 102 dB HL. The duration of
hearing loss for the subjects ranged from 7 to 41 years with
a mean of 20 years. One subject wore a hearing aid in his
unimplanted ear, six no longer wore hearing aids, and one
never worn one. The subjects reported having worn the
cochlear implant for a minimum of five and one-half months
to a maximum of five and one-half years. Estimates of daily
wearing time ranged from 8 to 18 hours a day, with a mean
wearing time of 13 hours a day. The subjects reported
having worn the cochlear implant for a minimum of five and
one-half years. Estimates of daily wearing time ranged from
8 to 18 hours a day,with a mean wearing time of 13 hours a
day. Information for the individual subjects is summarized
in Table 1.
Test Procedures
Preliminary Procedure
After the subject read and signed an informed consent
agreement, each was interviewed to establish an otological,
audiological, and amplification history. In addition, an
audiologist from the implant center was interviewed to

Table 1. Subject Information
Subject
Information
1
2
3
4
5
6
7
8
Gender
Female
Female
Female
Male
Male
Male
Female
Female
Etiology
?Cogan‘s
Syndrome
Meningitis
Unknown
Meningitis Noise
Trauma
Unknown
Meniner‘s
Syndrome
Unknown
Age at Onset of Hearing Loss (yrs)
6
34
17
33
25
30
27
49
Age When Implanted (yrs)
27
36
50,52
47
61
38
39
58
Implanted Ear
Left
Right
Left
Right
Left
Right
Right
Left
# of Programmed Electrodes
19
19
19
20
20
20
19
19
Electrodes Eliminated
20,21,22
13,21,22
1.2,3,4
21,22
21,22
21,22
20,21,22
1,21,22
Stimulation Mode
BP+2
BP+1
CG
BP+1
BP+1
BP+1
BP+2
BP+1
Encoder Strategy
F0F1F2
F0F1F2
F0F1F2
MPEAK
MPEAK
MPEAK
F0F1F2
MPEAK
Average Daily Wearing Time (hrs)
8-10
18
18
12-16
16-18
8-9
4-5
15-16
Months of Implant Experience
37
67
48
6
5.5
7
37
4

52
obtain her evaluation of each subjects' family support
system. The majority of subjects reportedly enjoyed a
"good" family support system.
To elicit an objective picture of the subject's
performance using the implant, each was given two subtests,
the 4-Choice Spondee Test and 10 sentences from the CID
Everyday Sentence Test, from The Minimal Auditory
Capabilities Battery (Owens, Kessler, Telleen, & Schubert,
1981). These materials and the test configuration were
selected based on the Cochlear Corporation test protocol for
individuals receiving their device. Scoring for both tests
was based on a percentage correct score. The percentage
correct score for the sentences was based on key word
scoring. Both tests were administered using only auditory
cues only with the speech processor worn at its usual
setting. The tests were administered in a sound-treated
audiological test suite, in sound field, with the subject
facing the output speaker at a distance of one meter. The
material was presented at an intensity of 70 dB SPL.
Results of these tests can be found in Table 2.
To obtain a subjective estimate of performance using
the implant, the subjects were asked to complete the
Performance Inventory for Profound and Severe Loss (PIPSL)
(Owens & Raggio, 1988). The PIPSL measures a person's
perception of their communicative performance and it is
especially designed for the individual with severe and/or

Table 2. Percentage correct results obtained on the 4-
Choice Spondee and the CID Everyday Sentences
Tests.
Ss
4-Choice Spondee
% Correct
CID Everyday Sentences* '
% Correct
1
90
22
2
100
53
3
100
30
4
100
75
5
60
31
6
100
67
7
70
3
8
100
1
* Ten sentences were presented

54
profound hearing loss. It consists of written responses to
58 items from six different categories:
(1) Understanding Speech with Visual Cues, which
evaluates the ability to understand connected
speech when the speaker's face is visible;
(2) Intensity. which describes the person's ability to
detect everyday sounds and their relative
loudness;
(3) Response to Auditory Failure, which addresses how
the person manages communication breakdowns;
(4) Environmental Sounds, which addresses issues of
recognizing familiar sounds auditorily only;
(5) Understanding Speech with No Visual Cues, which
evaluates speech understanding without visual
cues; and
(6) Personal. designed to elicit the patient's
feelings about their hearing loss.
Two other categories, Occupation and General are evaluated
separately. The former is evaluated in an employment
setting in three areas: (a) Understanding Speech with
Visual Cues, (b) Response to Auditory Failure, and (c)
Personal. The latter is made up of "general communication"
items that did not fit into any of the other categories,
e.g., "How often can you do something about poor lighting
that impairs your lipreading ability?" (Owens & Raggio,
1988, p. 54). The respondent is instructed to answer each

55
question based on the type amplification worn, if any, for
that particular situation. For each question there are six
possible responses that are assigned a value in the
following manner:
0 - Never
1 - Almost Never
2 - Occasionally
3 - About Half The Time
4 - Frequently
5 - Practically Always
6 - Always
If the person responds with "Does not apply", the item is
not scored. A mean score is obtained for each category with
the exception of the General and Occupation categories which
are interpreted separately. In fact, the authors state that
"all items can be treated singly in a rehabilitative
program..." (Owens & Raggio, 1988, p. 50). Owens and Raggio
(1988) also make the following recommendations.
Regarding the interpretation of an individual
profile, the use of percentage scores is not
warranted because of the small number of items
in each scale. Preferably, in discussing the
results with a client, the mean numerical scores
for the scales be treated according to the
corresponding descriptive terms, as follows:
0-0.4 (never), 0.5-1.4 (practically never),
1.5-2.4 (occasionally), 2.5-3.4 (about half the
time), 3.5-4.4 (frequently), 4.5-5.4 (practically
always), and 5.5-6.0 (always). (p. 50)
As can be seen in Fig. 1, the subjects in this study
exhibited a wide range of responses to the PIPSL categories,

e-1
2 -5K- 3 -B- 4 -X- 5 -0- 6 7 -S- 8
USV--Under3tandlnQ Speech with Vlaual Cues
INT--lntenalty
RAF--Reaponae to Auditory Failure
ES--Environmenlel Sounda
U3NV--Underatandlno Speech with No Vlaual Cuea
P Efl --Personal
Figure 1. Mean scores for Performance Inventory for Profound and Severe Loss (PIPSL)
ui
o^

57
and there was wide variability between subjects. Group
means and ranges are illustrated in Fig. 2 and four of the
areas describe the group's perception of their communication
abilities using thecochlear implant. They reported that
they frequently understood speech with visual cues, were
able to detect everyday sounds and their relative loudness,
and recognized familiar sounds using audition alone. In
addition, they were able to understand speech without visual
cues approximately half of the time.
Experimental Procedures
The experimental test procedures consisted of reading
the Grandfather Passage and counting backwards from 100 to
70 under simultaneous and delayed auditory feedback
(SAF/DAF). These tasks were performed in three different
conditions: (a) speech processor off, (b) speech processor
on, and (c) conventional amplification in the unimplanted
ear. To insure uniformity subjects were given written
instructions for the experimental tasks and an opportunity
to clarify any questions regarding the tasks.
Equipment
Equipment to conduct the test protocol for this
research consisted of the following: (a) the subject's
Nucleus 22 multichannel cochlear implant, speech processor,
and custom patch cord, (b) Phonic Mirror miniDAF PM 505, (c)
Unitron UE 12-PP L behind-the-ear hearing aid and audio

D High/Low "B~ Mean
USV--Under8tandlng Speech with Visual Cues
INT--lntenslty
HAF--Response to Auditory Failure
E3--Envlronmental Sounds
USN V--Under standi no Speech with No Visual Cues
PER--Peraonal
Figure 2. Group Mean Scores and Ranges for Performance Inventory for Profound and
Severe Loss (PIPSL)
ui
oo

59
input boot, (d) Unitron Direct Audio Input Kit, and (e) AIWA
cassette tape recorder with one-half inch microphone.
The functioning of the cochlear implant was checked
using the Nucleus 22-Channel Cochlear Implant System. This
system is composed of an IBM compatible microcomputer, the
dual processor interface (DPI), and customized software.
This system is used, initially, to create a ''map”, or
prescription, for the individual subject. The "map” is
created by attaching the speech processor to the DPI and
programming each electrode separately. The parameters for
the "map" are the patients' threshold (the softest level of
sound they reported hearing) and the maximum comfort level,
i.e., the loudest, comfortable level of sound. Each
subject's implant was checked prior to their participating
in the study. This was accomplished by attaching the speech
processor to the DPI and sweeping the electrodes, allowing a
comparison and confirmation of the speech processor "map"
and the last prescribed "map."
According to the manufacturer's product information
sheet, the Phonic Mirror miniDAF has a delay control setting
of approximately 25 milliseconds (ms) at position number 0
to a maximum delay of 220 ms at position number 10. The
effect of varying auditory feedback duration was
investigated by Black (1951). He reported that a minimal
delay of even 30 ms produced significantly longer reading
rates in his subjects. To insure that there was no

60
possibility of the 25 ms delay produced by the miniDAF unit
(0 dial selector control) influencing the subjects'
responses, all subjects were tested in the SAF condition
without their speech processor being connected to the
miniDAF. This necessitated using two separate microphones.
The recording microphone was connected to the AIWA cassette
tape recorder throughout all of the test conditions. An
additional microphone (Lapel Microphone AT 164), provided
with the miniDAF, was added during all the DAF test
procedures. It was recognized that the necessity of using
two microphones—one for recording and one for routing the
speaker's output through the DAF—was a limitation; however,
it could not be overcome with the available equipment. In
addition, there was an impedance mismatch between the
cochlear implant speech processor and the miniDAF unit. To
overcome this, a custom patch cord was provided by Phonic
Ear. It should also be noted that there was no frequency
shaping of the signal taking place as that signal was routed
through the DAF; therefore, the only change occurring was
the preset delay (R. Mendoza, personal communication, 1990).
To calibrate the miniDAF unit, a signal was generated
using Coulbourn instrument modules. This signal had a
duration of 20 milliseconds (ms) with an instantaneous
rise/fall time and a nominal frequency of 1000 Hz. The
output was delivered to a standard audiometric earphone
attached to the microphone of the miniDAF, and the

61
electrical output was fed into a Tektronix Type 533
oscilloscope. The delay time of the miniDAF was adjusted by
visually observing the output displayed on the oscilloscope.
Once a 200 ms signal rate was obtained the delay control
knob on the miniDAF was secured in a fixed position. At the
end of data collection, the delay time (200 ms) signal was
confirmed using the equipment and method described above.
Testing with conventional amplification and DAF was
accomplished using a Unitron UE PPL behind-the-ear hearing
aid and direct audio input. The use of the boot enabled the
experimenter to connect the hearing aid to the miniDAF. The
boot was set to exclude the hearing aid microphone thereby
preventing amplification of any environmental sounds. The
result of this arrangement was that only the subject's
speech was transmitted through the hearing aid and miniDAF
unit. The subjects wore a stock, regular style, earmold
during testing. The exception to this was one subject who
still wears a hearing aid in his unimplanted ear. He used
his own regular style earmold.
An electroacoustical analysis of the hearing aid (ANSI,
1976) was conducted at the beginning and the conclusion of
the study to confirm its performance based on the
manufacturer's specification data. Initially, coupling the
hearing aid to the miniDAF resulted in the output
overdriving the hearing aid. To overcome this problem it
was determined that 40 to 50 dB attentuation was needed (J.

62
Seamans, personal communication, 1990) . This was achieved
using the attentuator provided with the direct audio input
kit. The attenuator output was measured electoacoustically,
and the maximum attentuation recorded was 58 dB SPL. The
hearing aid volume control was set to midlevel (volume
setting 2) and was coupled to the attenuator. The
attentuator output was again measured as its output control
knob was rotated, and the knob was secured in a fixed
position when the attenuation provided was 18 dB of
attenuation (J. Seamans, personal communication, 1990).
Conditions
Three experimental conditions were evaluated: (a)
cochlear implant off, (b) cochlear implant on, and (c)
conventional amplification in the unimplanted ear. Two
experimental treatments were administered in each
experimental condition: (a) simultaneous auditory feedback
(SAF), and (b) delayed auditory feedback (DAF). These two
treatments were alternated in the following manner: SAF
with processor off/on, DAF with processor off/on, and SAF
with conventional amplification and DAF with conventional
amplification. SAF always preceded DAF in each condition
and was used as baseline data.
Methods and Materials
To determine the order of the presentation of the
experimental conditions (the speech processor "on" or

63
"off”), the "on” condition was designated an odd number and
the "off" condition was designated an even number. Using a
random numbers table, a number was selected for the first
subject. If that number ended in an odd number, the "on"
condition was selected as the first condition and the "off"
condition was number two. If the number selected was an
even number the "off" condition was selected as the first
condition, and in the second condition the speech processor
was "on". For subsequent subjects, the conditions were
counterbalanced based on the first subject (Hegde, 1987).
Written instructions for the reading and counting tasks
were given to each subject. They were asked to read the
Grandfather Passage silently in order to familiarize
themselves with the material. Any questions were answered
and they then read the passage aloud in the SAF condition.
Following the reading they were given the written
instructions for the counting task. They were initially
asked to count to themselves silently and then to count
aloud. The purpose of the silent counting was to allow them
to practice and not be so startled by the request that any
difficulties might be due to surprise at the request and not
to the test condition. The use of backwards counting to
obtain uniform speech sample material was selected based on
the consensus of the principal investigator and the advisory
committee. It was recognized that this task has
limitations. For example, older people may have more

64
difficulty with this type of task than younger people.
Interpretation of counting results in this study need to be
made with these limitations in mind. Pfeiffer (1975)
included backward counting in his, Short Potable Mental
Status Questionnaire (SPMSO) to test for cognitive
functioning in older adults, since this skill might be
related to cognitive decline in the elderly.
During DAF testing, the selected volume on the miniDAF
was based on the subject's reported comfort level. The
implant speech processor was connected directly to the
miniDAF unit in the previously described manner. A mouth-
to-microphone distance of 3 inches was maintained using a
head held microphone set-up and the lapel microphone (AT
164) provided with the miniDAF unit. This allowed the
subject's speech productions to be passed through the
miniDAF resulting in their hearing it with a 200 ms delay.
Following completion of the test protocol with the cochlear
implant the conditions were repeated with the subject
wearing the Unitron UE 12-PPL behind-the-ear hearing aid in
their unimplanted ears. The hearing aid internal controls
were set to provide the widest response, and the volume
setting was selected based on the subject's reported comfort
level. To determine test-retest reliability all of the
subjects were given one extra test condition that was
randomly selected and assigned prior to their participation
in the study. That condition was repeated in its entirety.

65
All of the subjects' responses were recorded on an AIWA
cassette tape recorder using a one-half inch clip
microphone. A mouth-to-microphone distance, for the
recording microphone, of 4.5 inches was maintained during
the testing.
Analysis of Data
Transcription
Consensus transcription (Shriberg, Kwiatkowski, &
Hoffmann, 1988), using the International Phonetic Alphabet
(IPA), was performed by a speech-language pathologist and
the experimenter on all of the subject's experimental speech
productions. A sound-by-sound analysis of the second and
fourth sentences of the Grandfather Passage (He dresses
himself in an old back frock coat usually several buttons
missing. A long beard clings to his chin giving those who
observe him a pronounced feeling of the utmost respect.) and
the following additional words from the passage: cracked.
upon, the. short. more. and modern was performed on the
subject's speech productions in the SAF and DAF conditions.
This sample was selected based on the frequency of
occurrence of the phonemes included in conversational
English (Mines, Hanson, & Shoup, 1978). The phonological
analysis was performed by the Programs to Examine Phonetic
and Phonologic Evaluation Records (PEPPER) Version 4.0
(Shriberg, 1986). PEPPER is a group of computer programs
designed to analyze speech data. It allows the investigator

66
to input phonetically transcribed speech samples and analyze
them for type and frequency of speech sound error. The
subject's utterances during counting were also transcribed
and analyzed in the same manner. Following transcription of
the samples, data were entered into the PEPPER program for
analysis. The program scanned consonant and vowel
productions for errors based on a standard adult model. The
model had been entered from a transcript of an adult,
female, General American speaker who read the Grandfather
Passage and counted backwards from 100 to 70. Possible
errors detected included omissions, substitutions, and
distortions that differed significantly from standards for
typical production suggested by Shriberg (1986).
Intertranscriber reliability was determined for 25% of
the samples. These were selected by assigning each taped
test condition a number between 1 and 112 and then drawing
25% of them out of a box. These samples were independently
transcribed by another speech-language pathologist.
Two commonly used techniques for calculating
interobserver reliability have been discussed by McReynolds
and Kearns (1983). The "total method" is based on
percentage agreement for the total number of observations in
a study. "Point-to-point" reliability tallies observer
agreement based on the occurrence and nonoccurrence of the
target behavior. These authors state that the first
technique is inappropriate because, although two observers

67
may agree on the total number of responses obtained,
agreement regarding the occurrence of the target behavior is
lacking. The weakness of the "point-to-point" method
"relates to the fact that the agreement level obtained is a
direct reflection of the rate of production of the target
behavior" (McReynolds & Kearns, 1983, p. 150-151). The
result is that in instances of extremely high or low rates
of observed behaviors, there is a "high probability that
agreement will be obtained based on chance alone"
(McReynolds & Kearns, p. 151). In an effort to avoid the
pitfalls mentioned above a 2X2 chi-square analysis for
independent samples was performed to determine reliability
between the transcribers (Huck, Cormier, & Bounds, 1974).
The obtained X2 = 17 3 8.41, df = 1, was significant beyond
the .001 level of confidence.
Statistical Analysis
The small sample (N = 8) in this study prohibited the
use of parametric statistics; therefore, a Friedman two-way
analysis of variance (ANOVA) was performed. In addition,
effect size (ES) was calculated for duration, consonant
errors, and vowel errors for reading and counting as well as
for the cochlear implant and hearing aid conditions. Null
hypotheses express the notion that a particular phenomenon
being studied is, in fact, not present. Cohen (1977) wrote
that the use of effect size to describe data is not intended
to suggest a cause and effect relationship but rather "it is

convenient to use the phrase 'effect size' to mean 'the
degree to which the phenomenon is present in the
population.' or 'the degree to which the null hypothesis is
false'" (p. 9-10). Regardless of the type of phenomenon
being studied, "the null hypothesis always means that the
effect size is zero" and " ...the larger this value, the
greater the degree to which the phenomenon under study is
manifested (Cohen, 1977, p. 10). This relationship also
carries over to sample size where "...the larger the ES
posited, other things (significance criterion, desired
power) being equal, the smaller the sample size necessary to
detect it" (Cohen, 1977, p. 11). Effect size can be
described in relative terms of "small", "medium, and large".
To describe these terms further, numerical values have been
defined: (a) a "small" effect size is 0.2, (b) "medium"
effect size is 0.5; and (c) "large size 0.8.
In summary, the research experiment was a factorial
design with 5 independent variables: (a) SAF, (b) DAF, (c)
conventional amplification, (d) speech processor off, and
(e) speech processor on. The dependent variables were: (a)
reading rate, (b) counting rate, and (c) occurrence of
speech errors. The experimental design can be described as
the subject's speech processor in two conditions (off, on)
by two experimental treatments (SAF, DAF). A third
condition was conventional amplification by two experimental
treatments (SAF, DAF). Due to the small sample size (N =

69
8), and the repeated measures taken on each subject, the
data were subjected to a Friedman two-way analysis of
variance (Marascuilo & McSweeney, 1977; Huck et al., 1974)'
and to calculations of effect size (Cohen, 1977). Finally,
test-retest reliability of the experimental conditions was
evaluated using the Pearson Product-Moment statistic.

CHAPTER IV
RESULTS
The purpose of this study was to investigate the effect
of delayed auditory feedback (DAF) on the speech production
of post-lingual cochlear implant users. In addition, the
subjects were also tested wearing conventional amplification
in their unimplanted ear. The specific research questions
formulated in this study were:
1. Is there a difference between the Simultaneous
Auditory Feedback (SAF) and Delayed Auditory
Feedback (DAF) conditions in the duration of
reading and counting by cochlear implant users?
2. Is there a difference between the SAF and DAF
conditions in the total number of consonant and
vowel errors made by cochlear implant users during
reading and counting tasks?
3. Is there a difference between the SAF and DAF
conditions in the duration of reading and counting
by cochlear implant users when wearing a hearing
aid alone?
4. Is there a difference between the SAF and DAF
conditions in the total number of consonant and
70

71
vowel errors by cochlear implant users when
wearing a hearing aid alone and performing reading
and counting tasks?
DAF Effect on Reading and Counting Duration
Means and Ranges
Reading and counting duration means and ranges (in
seconds) as a function of amplification type and feedback
condition are reported in Table 3 and illustrated in Figure
3 and Figure 4. Examination of reading duration means and
ranges revealed no differences between SAF and DAF in the
absence of amplification (SAF M = 50.2 s, DAF M = 49.0 s).
However, there were duration differences between the SAF and
DAF means when subjects were tested with the cochlear
implant (SAF M = 50.5 s, DAF M = 64.0 s) and the hearing aid
(SAF M = 49.1 s, DAF M = 63.0 s). Wide ranges in reading
duration were also noted when subjects wore either the
cochlear implant (44 - 102 s) or the hearing aid (43 -
107 s) .
Counting duration means remained similar under SAF/DAF
in the absence of amplification (SAF M = 32.3, DAF M =
32.7), with the cochlear implant (SAF M = 33.0, DAF M =
36.8), and with the hearing aid (SAF M = 32.0, DAF M =
35.1). However, counting duration varied among the subjects
for this experimental task.

72
Table 3. Duration means and ranges (in seconds) in three
conditions (no amplification,cochlear implant,
hearing aid) under simulataneous and delayed
auditory feedback (SAF/DAF) when reading
Grandfather Passage and counting backwards.
SAF
DAF
X
Ranges
X
Ranges
Amplification
Time/Seconds
Time/Seconds
Reading
None
50.2
43 - 57
49.0
40 - 57
*CI
50.5
44 - 57
64.0
44 - 102
**HA
49.1
44 - 58
63.0
43 - 107
Counting
None
32.3
19 - 49
32.7
20 - 50
*CI
33.0
22 - 48
36.8
23 - 59
**HA
32.0
17 - 49
35.1
18 - 49
*CI = Cochlear
Implant
**HA = Hearing Aid

COLUOOZQCO
100
80
60
40
20
0
None Cl HA None Cl HA
SAF DAF
D High/Low •& Mean
Figure 3. Reading duration means and ranges in three conditions, no amplification
(None), Cochlear Implant (Cl), and hearing aid (HA) under simultaneous
and delayed auditory feedback (SAF/DAF)

wazoomw
SAF DAF
G High/Low â– & Mean
Figure 4. Counting duration means and ranges in three conditions, no amplification
(None), cochlear implant (Cl), and hearing aid (HA) under simultaneous
and delayed auditory feedback (SAF/DAF)

75
ANOVA
A Friedman two-way analysis of variance (ANOVA) was
performed to answer each of the research questions. This
statistical method assigns ranks to each of the mean scores
in a group of data, yielding a mean rank score for each
condition. The greater the differences between the mean
rank scores, the greater the difference between the test
measures.
Duration
There were no significant differences in either the
duration of reading—X2(5, N = 8) =8.23, p. <.14—or the
duration of counting—X2(5, N = 8) = 9.96, p. <.07 — in the
SAF and DAF conditions, regardless of the absence or
presence of amplification. The mean rank scores for reading
and counting duration are summarized in Table 4 and Figure
5, and Table 5 and Figure 6, respectively.
Examination of reading mean rank scores in Table 4
revealed that in the absence of amplification the subjects'
scores were larger (3.19) in the SAF condition than in the
DAF condition (2.63) indicating that their reading duration
was longer under SAF. Opposite results were obtained with
the cochlear implant and the hearing aid. Mean rank scores
when the cochlear implant was worn were 3.50 (SAF) and 5.00
(DAF) and with the hearing aid 2.88 (SAF) and 3.81 (DAF)
suggesting that the subjects took longer to read the passage
when experiencing DAF with either type of amplification. To

76
Table 4. Mean rank scores and effect size values in three
reading conditions (no amplification, cochlear
implant, hearing aid) under simultaneous and
delayed auditory feedback (SAF/DAF).
(A)
Duration
Reading
Amplification
Device
None
Cl*
HA**
SAF
3.19
3.50
2.88
DAF
2.63
5.00
3.81
ES***
0.21
0.96
0.99
(B)
Consonant Errors
Amplification
Device
SAF
5.87
1.69
3.94
DAF
4.44
4.13
3.00
ES
0.22
0.76
0.44
(C)
Vowel Errors
Amplification
Device
SAF
3.75
2.44
3.25
DAF
5.50
3.81
2.94
ES
0.24
0.65
0.41
*CI = Cochlear Implant
**HA = Hearing Aid
***ES = Effect Size

77
Figure 5. Mean rank scores for reading duration

78
Table 5. Mean rank scores and effect size values in three
counting conditions (no amplification, cochlear
implant, hearing aid) under simultaneous and
delayed feedback (SAF/DAF).
Counting
(A)
Duration
Amplification
Device
None
Cl*
HA**
SAF
2.88
2.94
2.69
DAF
3.81
5.13
4.06
ES***
0.30
0.35
0.28
(B)
Consonant Errors
Amplification
Device
SAF
3.31
3.44
3.50
DAF
3.19
4.19
3.38
ES
0.19
0.52
0.17
(C)
Vowel Errors
Amplification
Device
SAF
4.06
2.88
3.38
DAF
3.06
4.31
3.31
ES
0.48
1.02
0.08
*CI = Cochlear Implant
**HA = Hearing Aid
***ES = Effect Size

79
Figure 6. Mean rank scores for counting duration

80
further evaluate these data, calculations of effect size
(ES) were performed (Cohen, 1977). As was stated in Chapter
3, effect size is not intended to imply a cause and effect
relationship but rather the degree to which a relationship
between two measures may exist (Cohen, 1977). A large
effect size would suggest that differences did exist between
two conditions, e.g., SAF and DAF. Effect size values for
reading duration are summarized in Table 4. A small ES
value (0.21) was seen without amplification, and very large
values were seen for both the cochlear implant (0.96) and
hearing aid (0.99) conditions.
Counting
The counting duration mean rank scores are summarized
in Table 5 and illustrated in Figure 6. These results
indicate that the subjects took longer to perform the
counting task under DAF (3.81) than under SAF (2.88). The
same pattern was observed when the cochlear implant was
worn, 5.13 (DAF) and 2.94 (SAF). This pattern continued
when the subjects wore the hearing aid under DAF (4.06) and
under SAF (2.69). As can be seen in Table 5, the counting
duration tasks results yielded the same pattern for ES
values in the absence of amplification, i.e., a small ES
value (0.30), that was noted in the reading data. Unlike
the reading data, this finding of small effect size also
held true for the cochlear implant (0.35) and hearing aid
(0.28) conditions.

81
DAF Effect on Number of Consonant and Vowel Errors
Means and Ranges
Means and ranges for consonant and vowel errors during
reading and counting are presented in Table 6 and Table 7,
and illustrated in Figures 7 through 10. All nonstandard
omissions, substitutions, and deletions of consonants and
vowels were counted as errors. Suggestions from the PEPPER
manual (1986) were used to determine if variations in
productions were standard, casual speech or errors.
Reading. Examination of Table 6 revealed small
differences in the number of reading consonant errors in the
absence of amplification (SAF M = 4.1, DAF M = 6.8), and
with the hearing aid (SAF M = 6.3, DAF M = 4.8). There were
large differences in the range of scores, however,
indicating wide variability among the subjects under SAF and
DAF. Vowel reading errors followed the same pattern, i.e.,
small differences between the SAF/DAF condition. The means
were 3.8 (SAF) and 5.5 (DAF) in the absence of amplifica¬
tion, 1.5 (SAF) and 2.6 (DAF) with the cochlear implant, and
3.1 (SAF) and 1.5 (DAF) with the hearing aid. The ranges
were smaller for vowel errors, with the exception of the no
amplification condition (SAF 1 - 17, DAF 1 - 25).
Counting. Means for consonant counting errors yielded
small differences between SAF/DAF without amplification (SAF
M = 14.1, DAF M = 12.6), with the cochlear implant (SAF M =

82
Table 6. Mean and ranges for consonant and vowel errors in
three conditions (no amplification, cochlear
implant, hearing aid) under simultaneous and
delayed auditory feedback (SAF/DAF) when reading
Grandfather Passage.
Consonant Errors
SAF
DAF
Amplification
X
#
Ranges
Errors
X
#
Ranges
Errors
None
5.8
2-15
6.8
1-18
*CI
4.1
1-11
6.8
3-15
**HA
6.3
2-15
4.8
2-9
Vowel Errors
SAF
DAF
Amplification
X
#
Ranges
Errors
X
#
Ranges
Errors
None
3.8
1-17
5.5
1-25
*CI
1.5
0-5
2.6
1-6
**HA
3.1
0-9
1.5
0-3
*CI = Cochlear Implant
**HA = Hearing Aid

83
Table 7. Means and ranges for consonant and vowel errors in
three conditions (no amplification, cochlear
implant, hearing aid) under simultaneous and
delayed auditory feedback (SAF/DAF) when counting
backwards.
Consonant Errors
Amplification
SAF
X Ranges
# Errors
DAF
X Ranges
# Errors
None
14.1
1-34
12.6
1-22
*CI
12.8
0-22
16.2
8-24
**HA
13.7
8-21
14.7
5-24
Vowel Errors
SAF
DAF
X
Ranges
X
Ranges
Amplification
#
Errors
# Errors
None
4.2
0-21
1.7
0-9
*CI
1.1
0-5
6.1
0-17
**HA
3.2
0-9
3.6
0-14
*CI = Cochlear Implant
**HA = Hearing Aid

ziid^Ecqujq: Oh. ldccccOocco
40
30
20
10
0
Figure 7. Means and ranges of consonant errors for reading in three conditions,
no amplification (None), cochlear implant (Cl), and hearing aid (HA)
under simultaneous and delayed auditory feedback (SAF/DAF)
X
None
Cl
SAF
HA
None
Cl
DAF
HA
D High/Low "& Mean

zi id IE qd LLi cc Ol^ lu cc cr O a: c/d
SAF DAF
0 High/Low â– & Mean
Figure 8. Means and ranges of vowel errors for reading in three conditions,
no amplification (None), cochlear implant (Cl), and hearing aid (HA)
under simultaneous and delayed auditory feedback (SAF/DAF)

zzd^cqluq: Oll lu cu cu O cc oo
40
30
20
10
0
Figure 9. Means and ranges of consonant errors for counting in three conditions,
no amplification (None), cochlear implant (Cl), and hearing aid (HA)
under simultaneous and delayed auditory feedback (SAF/DAF)
X
None
Cl
SAF
HA
None
Cl
DAF
HA
D High/Low -& Mean
oo
ON

ZZ) GO LUcr Ou_ LUccccO cc CO
SAF DAF
D High/Low â– & Mean
Figure 10. Means and ranges of vowel errors for counting in three conditions,
no amplification (None), cochlear implant (Cl), and hearing aid (HA)
under simultaneous and delayed auditory feedback (SAF/DAF)

88
12.8, DAF M = 16.2), and with the hearing aid (SAF M = 13.7,
DAF M = 14.7). However, the ranges for consonant counting
errors were very large in the SAF and DAF condition.
Means for vowel counting errors also yielded small
differences between SAF/DAF without amplification (SAF M =
4.2, DAF M = 1.7), with the cochlear implant (SAF M = 1.1,
DAF M = 6.1), and with the hearing aid (SAF M = 3.2, DAF M =
3.6). The pattern of a wide range of scores among the
subjects seen in the previous experimental conditions
continued for vowel counting errors.
ANOVA
Reading. The results of the Friedman two-way ANOVA
were X2(5, N = 8) = 11.64, p. <.04 and X2(5, N = 8) = 7.75,
£. <1.7, for reading consonant and vowel errors,
respectively. These findings revealed that the introduction
of DAF did not result in a significant difference in the
number of consonant or vowel errors for reading.
Mean rank scores for reading consonant errors are
summarized in Table 4 and Figure 11. They indicate a
greater number of errors under SAF (5.87) versus DAF (4.44)
in the absence of amplification. This pattern was repeated
when the subjects wore the hearing aid under SAF (3.94) and
under DAF (3.00). However, the pattern was reversed when
the subjects wore the cochlear implant. In that condition

89
Figure 11. Mean rank scores of consonant errors for reading

90
more consonant errors were produced under DAF (4.13) than
under SAF (1.69).
Examination of effect size for reading consonant errors
revealed small ES values (0.22) in the absence of amplifica¬
tion and with the hearing aid (0.44). A moderate ES value
(0.76) was noted with the cochlear implant.
Mean rank scores of vowel reading errors are summarized
in Table 4 and Figure 12. The DAF condition yielded larger
mean rank scores for reading vowel errors in the absence of
amplification (5.50) than in the SAF condition (3.75). This
was also the case when the subjects wore the cochlear
implant under DAF (3.81) versus under SAF (2.44). However,
reading vowel errors were smaller with the hearing aid under
DAF (2.94) than SAF (3.25). Small effect size values for
reading vowel errors were obtained without amplification
(0.24) and with the hearing aid (0.41). A moderate ES
value, 0.65, was obtained with the cochlear implant.
Counting. Statistical analysis of counting errors
revealed X2(5, N = 8) = 1.42, 2* <-92 for consonant errors
and X2(5, N = 8) = 3.67, p. <.59 for vowel errors. This
lack of significant differences between the SAF and DAF
conditions in the counting task followed the same pattern as
shown in the reading task.
Mean rank scores for counting consonant errors,
summarized in Table 5 and illustrated in Figure 13,
suggested that in the absence of amplification there was no

91
Figure 12. Mean rank scores of vowel errors for reading

92

93
difference between the number of errors produced under SAF
(3.31) and under DAF (3.19). The same pattern was suggested
by the hearing aid data with the mean rank scores being 3.50
(SAF) and 3.38 (DAF). Effect size values for both the
absence of amplification (0.19) and the hearing aid
condition (0.17) were very small, but were moderate (0.52)
for the cochlear implant.
Mean rank scores for vowel counting errors are
summarized in Table 5 and illustrated in Figure 14. These
scores indicated that the smallest differences between SAF
(3.38) and DAF (3.31) were obtained with the hearing aid.
This was also supported by the very small ES value (0.08).
Without amplification the mean rank scores for vowel
counting errors were 4.06 (SAF) and 3.06 (DAF) with a small
ES value (0.48). The largest number of vowel counting
errors were obtained when the subject wore the cochlear
implant in the presence of DAF. In that condition the mean
rank scores were 2.88 (SAF) and 4.31 (DAF) with an ES value
of 1.02.
Performance with Cochlear Implant Versus Hearing Aid
The subjects in this study wore cochlear implants
because they had received little or no benefit from a
hearing aid. However, a large effect size was obtained for
some of the conditions with both the cochlear implant and
the hearing aid. A comparison of the cochlear implant (Cl)

Figure 14. Mean rank scores of vowel errors for counting

95
and the hearing aid (HA) under SAF/DAF is summarized in
Table 8-9 and Figures 15-18.
Duration
A review of reading and counting duration indicated
small differences in mean rank scores for reading (Cl =
3.50, HA = 2.88) and counting (Cl = 2.94, HA = 2.69) under
SAF. The ES values, 0.31 (reading) and 0.10 (counting),
indicated that there were small differences between the two
devices for reading duration and no differences between the
devices for counting duration. The DAF reading duration
data revealed that the mean rank scores for the cochlear
implant were 5.00 and for the hearing aid 3.81 and a very
small ES value of 0.04. The DAF counting duration data also
revealed small differences in mean rank scores for the
cochlear implant (5.13) and the hearing aid (4.06) and a
small ES value (0.32).
Consonant Errors
The mean rank score for consonant errors in reading
under SAF was 1.69 with the cochlear implant and 3.94 with
the hearing aid, yielding a moderate ES value of 0.59. The
introduction of DAF resulted in opposite findings with the
cochlear implant mean rank score of 4.13 and the hearing aid
3.00. A moderate ES value of 0.61 was obtained for this
comparison. In the SAF condition, the counting consonant

96
Table 8. Mean rank scores and effect size values with two
amplification devices under simultaneous auditory
feedback (SAF).
Reading
Duration
Consonant
Vowel
Errors
Errors
*CI
3.50
1.69
2.44
**HA
2.88
3.94
3.25
***ES
0.31
0.59
0.65
Counting
Duration
Consonant
Vowel
Errors
Errors
Cl
2.94
3.44
2.88
HA
2.69
3.50
3.38
ES
0.10
0.14
0.74
*CI = Cochlear Implant
**HA = Hearing Aid
***ES = Effect Size

97
Table 9. Mean rank scores and effect size values with two
amplification devices under delayed auditory
feedback (DAF).
Reading
Duration
Consonant
Vowel
Errors
Errors
*CI
5.00
4.13
3.81
**HA
3.81
3.00
2.94
***ES
0.04
0.61
0.81
Counting
Duration
Consonant
Vowel
Errors
Errors
Cl
5.13
4.19
4.31
HA
4.06
3.38
3.31
ES
0.32
0.24
0.42
*CI = Cochlear Implant
**HA = Hearing Aid
***ES = Effect Size

98
Figure 15. Comparison of reading mean rank scores between
the cochlear implant (Cl) and the hearing aid
(HA) under simultaneous auditory feedback (SAF)

99
Duration Cons Errors Vowel Errors
â–  ha
Figure 16. Comparison of reading mean rank scores between
the cochlear implant (Cl) and the hearing aid
(HA) under delayed auditory feedback (DAF)

100
6
5
M 4
Duration Cons Errors Vowel Errors
Figure 17. Comparison of counting mean rank scores between
the cochlear implant (Cl) and the hearing aid
(HA) under simultaneous auditory feedback (SAF)

101
â–  ha
Figure 18. Comparison of counting mean rank scores between
the cochlear implant (Cl) and the hearing aid
(HA) under delayed auditory feedback (DAF)

102
task yielded no differences between the cochlear implant and
the hearing aid with similar mean rank scores for both
devices and a small ES value (0.24).
Vowel Errors
The SAF reading condition yielded mean rank scores for
vowel errors of 2.44 (Cl) and 3.25 (HA) and a moderate ES
value (0.65). The mean rank scores for vowel counting
errors under SAF were 2.88 (Cl) and 3.38 (HA); the ES value
was moderate (0.74). The DAF reading condition yielded mean
rank scores of 3.81 (Cl) and 2.94 (HA). The ES value for
this comparison was large (0.81). Counting vowel errors
under DAF indicated similar mean rank scores 4.31 (Cl) and
3.31 (HA) with a small ES value (0.42).
Summary
In summary, statistical analysis of the data did not
reveal significant differences in duration or in the
occurrence of consonant or vowel errors regardless of type
of amplification or auditory feedback. The conditions
yielding a moderate to large effect size suggested
differences between the conditions (SAF/DAF) and the devices
(cochlear implant/hearing aid); however, because of the
small sample, the stability of the effect could not be
evaluated.
Pearson Product-Moment correlations were performed to
evaluate test-retest reliability of the difference

experimental conditions. High positive correlations were
obtained for all the conditions and are reported in Table
10. All of the correlations were significant beyond the
0.01 level of confidence.

104
Table 10. Correlations of test-retest reliability of
experimental conditions
Condition
Reading
Significance
Counting
Significance
Duration
.99
0.0001*
.99
0.0001*
Consonant
Errors
.93
0.0006*
.93
0.0006*
Vowel
Errors
.83
0.0051*
.95
0.0002*
* p < .01 level of significance

CHAPTER V
DISCUSSION
Reading and Counting Duration
The subjects in this study did not exhibit an apparent
DAF effect in duration of reading or counting backwards in
the absence of any amplification (neither cochlear implant
nor hearing aid) as evidenced by the nonsignificant
statistical findings for these measures. This conclusion
was further supported by the small effect size (ES) values
obtained for reading and counting duration. The reader will
recall that ES values suggest the likelihood of a phenomenon
being present in a sample, or in this instance, the
likelihood that reading and counting duration differences
are the result of changes in auditory feedback. The
duration results confirmed the lack of auditory feedback for
self-monitoring of speech production in these profoundly
hearing-impaired subjects.
Large ES values for reading with the cochlear implant
(0.96) and the hearing aid (0.99) lend support to the
possibility of true differences between the SAF and DAF
conditions. Examination of mean rank scores demonstrated
that the direction of the difference was toward the DAF
condition with both amplification devices, i.e., subjects
105

106
took longer to read the passage under DAF versus SAF with
the cochlear implant and with the hearing aid. This finding
that subjects took longer to read when wearing the hearing
aid agreed with the findings of increased reading duration
under DAF by hearing-impaired children wearing hearing aids
reported by Maxon et al. (1987).
Small ES values for counting duration did not strongly
support the possibility of an effect due to variations in
auditory feedback, However, mean rank scores did
demonstrate that subjects took longer to count under DAF
than under SAF for all three conditions (no amplification,
cochlear implant, and hearing aid). Maxon et al. (1987) had
also reported a DAF effect when their subjects performed a
rote task of counting from 1 to 10. The ES for the counting
duration task was only 0.28 in this study and would seem to
suggest that the likelihood that there was a DAF effect was
very small. A possible reason for lack of agreement with
the Maxon et al. (1987) study is that the children in their
study were counting forward, and the adults in the present
study were counting backward. A review of the DAF
literature did not reveal any studies involving backward
counting, and, therefore, normative data were not available
for comparison. However, it is known that some people are
less susceptible to DAF than others, e.g., Borden and Harris
(1984) noted that the DAF effect can be overridden if the
speaker attends to the reading task and ignores the acoustic

107
information being received. Perhaps during the counting
task the subjects were not monitoring the sound of their
speech but were more focused on the actual task. This is
further supported by the recorded data in which one of the
subjects is obviously increasng her speaking rate during the
task. Another reason for the apparent lack of difference
between SAF/DAF is that in the reading condition the
subjects, by the nature of the task, tried to maintain more
natural prosody and intonation, and their strategy appeared
to be to slow their speaking rate.
Consonant Errors
Reading
There were no significant differences between the SAF
and DAF conditions for consonant errors during reading.
However, a review of the raw data indicated small
differences between the means for SAF and DAT in the absence
of any amplification and when the cochlear implant or the
hearing aid was worn. What was immediately apparent from
the data was the wide range in the number of consonant
errors produced by the subjects in each of the reading
conditions (no amplification, cochlear implant, and hearing
aid). A moderate ES value (0.76) suggested support for a
possible DAF effect for consonant reading errors when the
subjects wore the cochlear implant. Small ES values with
the hearing aid (0.44) and in the absence of amplification

108
(0.22) only equivocally suggested a DAF effect. Examination
of the mean rank scores revealed that more reading consonant
errors occurred under SAF than under DAF when the subjects
wore the hearing aid and when they received no
amplification. The opposite finding was noted when the
subjects wore the cochlear implant. The reason for a
possible DAF effect operating when the subjects wore the
cochlear implant is explained by a review of how the
cochlear implant transmits auditory information. The
cochlear implant bypasses the damaged or absent hair cells
in the inner ear and directly stimulates the nerve cells,
thereby transmitting the auditory information directly to
the brain for interpretation. The coding strategy of
fundamental (F0), first formant (FI), and second formant
(F2) frequency information allows the person more accurate
auditory frequency information for self-monitoring. The
hearing aid provides less discrete information due to the
nature and degree of the hearing loss and the limitations of
the device itself.
Counting
The descriptive data for consonant counting errors
indicated small differences in the mean scores for SAF and
DAF. The pattern of wide ranges between subjects in the
number of errors was similar to that noted for consonant
reading errors. Effect size values in the absence of any
amplification (0.19) or when the hearing aid was worn (0.17)

109
did not suggest the possibility of a DAF effect operating.
The presence of a moderate (0.52) ES value, with a higher
mean rank score under DAF, suggested the possibility of a
DAF effect when the subjects wore the cochlear implant. As
previously discussd this possibility would be expected based
on the type of auditory information provided by the cochlear
implant versus the hearing aid. However, this explanation
is offered with the caveat that the nature of the counting
task itself may be confounding the results.
Vowel Errors
Reading
The pattern of wide ranges in the number of errors
evident in the consonant reading data was also noted in the
vowel data. This was true for all of the reading conditions
(no amplification, cochlear implant, and hearing aid). The
subjects produced more vowel reading errors under DAF than
under SAF in the absence of amplification and with the
cochlear implant. A moderate ES value (0.76) supported the
possibility of a DAF effect when the subjects wore the
cochlear implant. The cochlear implant coding strategy of
F0F1F2 provides vital information for vowel perception,
because vowel perception is contingent upon F1F2
information. Basal (high frequency) electrodes along the
basilar membrane provide F2 information, and apical (low
frequency) electrodes provide FI information (Patrick &

110
Clark, 1991). Examination of the means and ranges with the
hearing aid revealed that the subjects produced more vowel
reading errors under the SAP condition than under DAF. The
pattern of wide variability among the subjects continued and
was noted to be larger in the SAF than in the DAF condition.
The small ES value supported the finding of no real
differences between SAF and DAF when the subjects wore a
hearing aid.
Counting
Vowel errors in counting, as in reading, revealed the
wide differences between the subjects for this task. In the
absence of amplification, the descriptive data indicated
that the subjects made more errors in the SAF condition.
There was also a wider range in the number of errors among
the subjects. The ES value (0.48) was approaching the
moderate range, and the mean rank score was also in the
direction of more errors under SAF than DAF. If this effect
size did represent real differences between the SAF/DAF
conditions, the explanation may lie in the subjects'
becoming more familiar and comfortable with the backward
counting task. The hearing aid condition indicated no
difference between the SAF/DAF conditions with a very small
ES value (0.08) being obtained. The cochlear implant
condition was the opposite of the hearing aid condition with
more vowel errors produced in the DAF counting condition
than in the SAF condition. The possibility, of a DAF effect

Ill
was strongly supported by a very large ES value (1.02). The
differences between SAF and DAF for the counting vowel
errors is thought to be due to the subjects' monitoring
their speech output more closely than previously. The
reader should recall that the subjects demonstrated a
moderate ES value for the consonant counting task (0.52),
and also that the cochlear implant speech coding strategy
provides critical information for vowel perception (F1F2).
Therefore, if a DAF effect was occurring, it would be
anticipated that it would be larger for vowels because the
delay may have caused more auditory misinformation and
confusion for the subjects, resulting in a larger number of
vowel counting errors than consonant counting errors.
Cochlear Implant Versus Hearing Aid
The subjects' performance with the cochlear implant and
with the hearing aid was evaluated under SAF and DAF. The
areas evaluated were: (a) duration, (b) consonant errors,
and (c) vowel errors.
Duration
A review of reading duration means and ranges indicated
that there was no difference between the cochlear implant
and the hearing aid under SAF/DAF. However, mean rank
scores indicated that the subjects took longer to read the
passage and to count in both the SAF and DAF conditions with
the cochlear implant than with the hearing aid. Each of the

112
eight subjects in this study was able to describe the delay
when wearing the cochlear implant. Their descriptions of
the delay included: (a) "Sounds like a terrible echo," (b)
"Sounded terrible," (c) "My voice sounded lower, the echo
sounded high pitch," and (d) "Seems like the voice is coming
after me." One of the subjects inquired, "How much delay on
it... it's too much, it's confusing." None of the subjects
were able to describe the DAF when wearing the hearing aid.
They reported only that it was a loud sound or that they did
not hear anything. The subjective descriptions of the DAF
condition when the cochlear implant was worn and the
increase in reading time support the likelihood that the
subjects were monitoring their speech output based on
auditory cues. The suggestion of a DAF effect on reading
duration when the hearing aid was worn may have been the
result of the noise alone being so annoying and distracting
that the subjects were unable to ignore it. The result was
that it took them longer to read the passage under DAF.
Consonant Errors
The data for consonant errors for reading and counting
indicated errors in the SAF condition when they wore the
cochlear implant than when they wore the hearing aid. The
reverse was true in the DAF condition, i.e., more errors
were made under DAF with the cochlear implant than with the
hearing aid. This could have been expected because, as was
previously discussed in this chapter, the coding strategy of

113
the cochlear implant provided the subjects with more
accurate auditory information then they received with the
hearing aid. Therefore, under SAF they were monitoring
their speech and able to maintain speech production targets.
This was more evident for the reading data than for the
counting data again, suggesting the influence of the task.
In other words, under counting the subjects were performing
a rote task and not paying as much attention to their
speech.
Vowel Errors
A comparison of vowel reading and counting errors with
the cochlear implant and with the hearing aid indicated a
pattern similar to that found for the consonant errors. The
subjects produced fewer errors under SAF, reflecting the
quality and quantity of auditory information provided by the
cochlear implant. The introduction of DAF yielded more
errors. In fact, the ES value (1.02) supported the argument
for the presence of a DAF effect.
Types of Speech Errors
One of the research questions in this study addressed
the total number of consonant and vowel errors made by the
subjects. The PEPPER program allowed the type of errors to
be identified, as well as the number of errors. The types
of errors made by the subjects included deletions,
substitutions, and distortions. These are the same types of

114
errors reported by Fairbanks and Guttman (1958) for their
normal-hearing subjects.
Cochlear Implant
Consonants. A review of Table 11 indicated that the
subjects produced more consonant errors under DAF versus SAF
during both the reading and the counting tasks. The
majority of errors for both SAF/DAF and reading/counting
were identified as deletions.
Vowels. Vowel errors with the cochlear implant are
presented in Table 12. The pattern of more errors being
produced under DAF is repeated, as it was for consonants,
with the exception of more substitution errors being made
under SAF for reading.
Hearing Aid. The subjects produced more consonant and
vowel errors under SAF than DAF in reading when they wore
the hearing aid. These data are summarized in Tables 13 and
14.
Consonants. When the subjects wore the hearing aid
during the reading task, the total number of errors produced
was greater in the SAF condition. Reviewing Table 13
indicated that more deletion and distortion errors occurred
under SAF than under DAF whereas more substitution errors
occurred under DAF.
During the counting tasks, subjects produced more
errors under DAF than under SAF. The breakdown of

115
Table 11. Comparison of frequency and type of reading and
counting consonant errors for 8 subjects under
simultaneous and delayed auditory feedback
(SAF/DAF) and wearing a cochlear implant (Cl)
Type and Frequency
of
Condition
Task
Consonant Errors
Deletions Substitutions
Distortions
Total
CI/SAF
Reading
22
10
2
34
CI/DAF
Reading
32*
14*
7*
53
CI/SAF
Counting
99
2
2
103
CI/DAF
Counting
115*
12*
3*
130
* Larger number of SAF/DAF pair

116
Table 12. Comparison of frequency and type of reading and
counting vowel errors for 8 subjects under
simultaneous and delayed auditory feedback
(SAF/DAF)
and wearing a cochlear
implant (Cl)
Condition
Task
Type and Frequency
of
Vowel Errors
Deletions Substitutions
Distortions
Total
CI/SAF
Reading
1
9*
2
12
CI/DAF
Reading
2*
6*
12*
20
CI/SAF
Counting
7
1
1
9
CI/DAF
Counting
9*
6*
34*
49
* Larger number of SAF/DAF pair

117
Table 13. Comparison of frequency and type of reading and
counting consonant errors for 8 subjects under
simultaneous and delayed auditory feedback
(SAF/DAF) and wearing a hearing aid (HA)
Type and Frequency
of
Consonant Errors
Condition Task Deletions Substitutions Distortions Total
HA/SAF
Reading
36*
8
9*
53
HA/DAF
Reading
24
10*
4
38
HA/SAF
Counting
104
2
4
110
HA/DAF
Counting
111*
6*
5
118
* Larger number of SAF/DAF pair

118
Table 14. Comparison of frequency and type of reading and
counting vowel errors for 8 subjects under
simultaneous and delayed auditory feedback
(SAF/DAF) and wearing a hearing aid (HA)
Type and Frequency
of
Vowel Errors
Condition Task Deletions Substitutions Distortions Total
HA/SAF
Reading
5*
12*
12*
29*
HA/DAF
Reading
1
6
4
11
HA/SAF
Counting
10
0
7
17
HA/DAF
Counting
13*
1*
16*
30
* Larger number of SAF/DAF pair

119
types of errors indicated that the greatest number of errors
were deletions.
Vowels. A review of Table 14 revealed a repetition of
the pattern seen in the consonant hearing aid data, i.e.,
subjects produced more reading errors under SAF and more
counting errors under DAF. The greatest number of
individual errors for reading were found to be equal between
substitutions and distortions. during the counting task the
greatest number of errors occurring were distortions.
Cochlear Implant Versus Hearing Aid
A comparison of the subjects' performance with the
cochlear implant versus the hearing aid is presented in
Table 15 for consonant errors and Table 16 for vowel errors.
Consonant Reading Errors SAF/DAF
The subjects produced more total consonant errors when
they wore the hearing aid under the SAF condition than when
they wore the cochlear implant. Deletions represented the
largest number of error for both the cochlear implant and
the hearing aid conditions.
In the DAF condition, the subjects produced more total
consonant errors when they wore the cochlear implant than
when they wore the hearing aid. The majority of errors were
of the deletion type.

120
Table 15. Comparison of frequency and type of reading and
counting consonant errors for 8 subjects wearing
a cochlear implant (Cl) or a hearing aid (HA).
Type and Frequency
of
Consonant Errors
Condition
Task Deletions
Substitutions
Distortions
Total
CI/SAF
Reading
22
10*
2
34
HA/SAF
Reading
36
8
9*
53
CI/DAF
Reading
32*
14*
7*
53
HA/DAF
Reading
24
10
4
38
CI/SAF
Counting
99
2
2
103
HA/SAF
Counting
104*
2
4*
110
CI/DAF
Counting
115*
12*
3*
130
HA/DAF
Counting
111
5
2
118
* Larger number of CI/HA pair

121
Table 16. Comparison of frequency and type of reading and
counting vowel errors for 8 subjects wearing a
cochlear implant (Cl) or a hearing aid (HA).
Type and Frequency
of
Consonant Errors
Condition Task Deletions Substitutions Distortions Total
CI/SAF
Reading
1
9
2
12
HA/SAF
Reading
5*
12*
12*
29
CI/DAF
Reading
2*
6
12
20
HA/DAF
Reading
1
6
4
11
CI/SAF
Counting
7
1*
1*
9
HA/SAF
Counting
10
0
7*
17
CI/DAF
Counting
9
6*
34*
49
HA/DAF
Counting
13
1
16
30
* Larger number of CI/HA pair

122
Consonant Counting Errors SAF/DAF
The total number of consonant counting errors was
greater with the hearing aid than with the cochlear implant
under SAF. The majority of errors produced continued to be
deletions.
Under the DAF condition the pattern of errors reversed
with more consonant errors being produced when the subjects
wore a the cochlear implant than when they wore the hearing
aid. Deletions continued to represent the greatest number
of errors.
In summary, reviewing the type and occurrence of
consonant errors revealed that subjects made more errors
with the hearing aid than with the cochlear implant during
the reading and counting tasks performed under SAF. When
the reading and counting tasks were repeated more errors
were made under DAF when the cochlear implant was worn.
These findings reflect the difference in the types of
auditory feedback the subjects received with these devices.
The cochlear implant provided discrete information by
directly stimulating the nerve cells and by passing damaged
or absent hair cells in the cochlea. Therefore, the
auditory information the subjects received during SAF was
more accurate and complete compared to the auditory
information provided by the hearing aid. The result was
that subjects made more errors whjen they wore the hearing
aid and performed the experimental tasks under SAF. The

123
reverse finding of an increased in errors when they wore the
cochlear implant under DAF gave support to the position that
these subjects were self-monitoring their speech productions
and that they were experiencing a DAF effect as their error
types were similar to those for normal-hearing subjects
under DAF reported by Fairbanks and Guttman (1958).
Vowel Reading Errors SAF/DAF
The subjects produced more total vowel errors when
wearing the hearing aid than when wearing the cochlear
implant under SAF. The largest number of errors was divided
equally between substitutions and distortions. When they
performed the reading task under DAF, they made more errors
when they wore cochlear implant. In the DAF condition, the
largest number of errors were distortions.
Vowel Counting Errors SAF/DAF
The same pattern of more errors produced when the
subjects wore the hearing aid under SAF than when they wore
the cochlear implant continued for vowel counting errors.
Deletions made up the majority of errors, a change from the
reading task.
The DAF condition yielded a greater number of errors
when the subjects wore the cochlear implant than when they
wore the hearing aid. Distortion again was the largest type
of errors as it had been for the reading task.

124
In summary, the vowel reading and counting data reflect
the same pattern that was demonstrated in the consonant
data, i.e., the subjects made fewer errors when they wore
the cochlear implant than when they wore the hearing aid in
the SAF condition. This pattern was reversed with the
introduction of the DAF. As was discussed previously, the
type and amount of auditory feedback available to the
subjects with the two devices helped to explain the
direction of the error patterns. The subjects' performance
also gave support to the position that they were
experiencing some degree of DAF effect.
Summary
The purpose of this study was to investigate the effect
of delayed auditory feedback (DAF) on the speech production
of adult post-lingually deafened cochlear implant users.
The following was found:
1. Duration—SAF/DAF. The subjects took longer to
read the Grandfather Passage under DAF than under
SAF with the cochlear implant and the hearing aid.
There was no apparent difference in counting
duration between SAF and DAF.
2. Total Number of Errors—SAF/DAF. The subjects
produced more consonant reading errors under DAF
than SAF with the cochlear implant and the hearing
aid. More vowel reading errors were produced
under DAF than SAF with the cochlear implant, but

125
fewer errors under DAF with the hearing aid. More
consonant counting errors were produced under DAF
than SAF when the subjects were wearing either the
cochlear implant or the hearing aid. The subjects
produced more vowel counting errors with the
cochlear implant under DAF than SAF. They
produced more vowel errors in the SAF than DAF
when they wore the hearing aid.
3. Duration—Cochlear Implant/Hearino Aid. There was
no difference between the duration of reading and
counting with the cochlear implant versus the
hearing aid. The subjects took longer to read the
passage and count backward under DAF than SAF with
both the cochlear implant and with the hearing
aid.
4. Total Number of Errors—Cochlear Implant/Hearina
Aid. The subjects made more consonant and vowel
reading errors under DAF with the cochlear implant
than the hearing aid. There were no differences
between the cochlear implant and the hearing aid
in the occurrence of consonant and vowel errors.
More vowel counting errors were produced under DAF
than SAF when the subjects wore the cochlear
implant and when they wore the hearing aid.

126
Conclusions
Although the findings in this study were not
statistically significant, compelling evidence was available
in terms of moderate to large effect size values for some
experimental conditions (e.g., reading duration), indicating
the existence of a DAF effect. However, the stability of
the effect size could not be demonstrated due to the small
sample size and the inability to perform further statistical
analysis on the data. Examination of mean rank scores also
supported the possibility that a DAF effect was occurring.
Additional indications of support for the presence of a DAF
effect on the speech production of these subjects included:
1. The subjects' descriptions of their auditory
feedback under DAF,
2. The transcribers' observations of differences in
the subjects' speech during DAF,
3. The high correlations demonstrated for the test-
retest conditions, and
4. The excellent intertranscriber reliability.
Further research is warranted to explore the effect of
DAF on the speech production of cochlear implant users in
order to better understand the artifically reinstated
auditory feedback provided to this population by the
cochlear implant. Areas of study might include a study of a
larger group of subjects to allow statistical evaluation of
the effect of DAF on the speech of cochlear implant users or

127
a listener comparison study to evaluate changes in the
speech productions of the cochlear implant users under
SAF/DAF.
Further study of the DAF effect in hearing aid users is
also warranted. Custom earmolds would have provided a
better coupling device than the stock earmolds. This would
have been expected to reduce, if not eliminate, feedback
problems which occurred as the volume control was increased
on the hearing aid. Additional studies might include a
comparison of the effect of DAF on hearing aid users with
moderate, severe, and profound hearing loss. The
documentation of a DAF effect with hearing aid users would
lend support for the use of DAF in evaluation of potential
cochlear implant candidates. In addition, a study of normal
hearing subjects under distorted DAF would be of interest.
If the DAF signal were distorted by frequency shaping to
result in an unintelligible version of the subject's
auditory feedback, would the effect on reading duration be
similar to that found for these cochlear implant users in
the hearing aid DAF condition?

APPENDIX 1
TOTAL NUMBER OF CONSONANT ERRORS DURING READING
Subject
Cochlear
On
Implant
Off
Hearing Aid
On
SAF
DAF
SAF
DAF
SAF
DAF
1
11
15
15
18
15
9
2
3
11
5
5
9
4
3
2
5
5
7
2
4
4
4
4
5
5
8
6
5
2
6
3
5
3
2
6
5
7
7
7
. 7
7
7
5
3
5
7
5
5
8
1
4
2
1
2
2
Total
33
55
47
55
51
39
128

APPENDIX 2
TOTAL NUMBER OF VOWEL ERRORS DURING READING
Subject
Cochlear
On
Implant
Off
Hearing Aid
On
SAF
DAF
SAF
DAF
SAF
DAF
l
5
6
4
7
3
2
2
1
5
1
2
7
0
3
1
1
17
25
9
2
4
2
2
2
3
4
3
5
0
2
1
2
0
1
6
2
1
2
2
2
2
7
1
2
3
2
0
1
8
0
2
1
1
0
1
Total
12
21
31
44
25
12
129

APPENDIX 3
TOTAL NUMBER OF CONSONANT ERRORS DURING COUNTING
Subject
Cochlear
On
Implant
Off
Hearing Aid
On
SAF
DAF
SAF
DAF
SAF
DAF
1
21
22
12
15
11
15
2
10
14
15
11
15
10
3
15
24
34
22
18
19
4
9
9
8
9
8
9
5
0
17
3
4
9
24
6
22
20
19
18
21
21
7
17
16
23
21
19
15
8
9
8
1
1
9
5
Total
103
130
115
101
110
118
130

APPENDIX 4
TOTAL NUMBER OF VOWEL ERRORS DURING COUNTING
Subject
Cochlear
On
Implant
Off
Hearing Aid
On
SAF
DAF
SAF
DAF
SAF
DAF
1
1
8
0
0
0
5
2
0
17
5
1
6
0
3
3
16
21
9
8
7
4
0
0
1
0
0
0
5
0
5
0
0
0
14
6
0
1
0
0
0
0
7
5
2
7
4
3
3
8
0
0
0
0
0
0
Total
9
49
34
14
17
29
131

APPENDIX 5
DURATION, IN SECONDS, DURING READING
Cochlear Implant Hearing Aid
On Off On
Subject
SAF
DAF
SAF
DAF
SAF
DAF
1
55
101
55
55
53
107
2
45
55
48
45
47
46
3
56
55
52
47
49
47
4
52
102
57
55
58
103
5
50
49
47
50
45
48
6
44
44
43
43
• 44
57
7
52
47
45
40
46
43
8
50
59
55
57
51
53
Total
404
512
402
392
393
504
132

APPENDIX 6
DURATION, IN SECONDS, DURING COUNTING
Cochlear Implant Hearing Aid
On Off On
Subject
SAF
DAF
SAF
DAF
SAF
DAF
1
23
30
24
26
24
39
2
33
42
34
34
35
36
3
25
23
19
20
17
18
4
48
59
49
50
49
49
5
46
46
44
42
43
48
6
38
36
35
38
36
40
7
22
24
21
20
22
20
8
29
35
33
32
30
31
Total
264
295
259
262
256
301
133

REFERENCES
American National Standards Institute (1976). Methods of
measurement of electoacoustical characteristics of
hearing aids. (ANSI S3.2 1976). New York: Author.
Ballantyne, J. (1985). The results from various
viewpoints. In R. F. Gray (Ed.), Cochlear Implants
(pp. 180-193). San Diego: College-Hill Press.
Berliner, K. I., Tonokawa, L. L., Dye, L. M., & House, W. F.
(1989). Open-set speech recognition in children with a
single-channel cochlear implant. Ear and Hearing. 10,
237-242.
Bilger, R. C. (1983). Auditory results with single-channel
implants. Annals of the New York Academy of Sciences.
405. 337-342.
Binnie, C. A., Daniloff, R. G., & Buckingham, H. W. Jr.
(1982). Phonetic disintegration in a five-year-old
following sudden hearing loss. Journal of Speech and
Hearing Disorders. 47. 181-189.
Black, J. W. (1951). The effect of delayed side-tone upon
vocal rate and intensity. Journal of Speech and
Hearing Disorders. 16, 56-60.
Boothroyd, A. C. (1987). Perception of speech pattern
contrasts using a multichannel cochlear implant. Ann.
Otol. Rhinnnol. Larvngol.. 96 (Suppl. 128), 58-62.
Boothroyd, A. C. (1988, May). Assessment of speech
production in cochlear implants. In R. I. Kohut
(Chair), Cochlear Implants. NIH Consensus Development
Conference. Washington, D.C.
Borden, G. J., & Harris, K. S. (1984). Speech science
primer: Physiology, acoustics, and perception of
speech (2nd ed.) Baltimore: Williams and Wilkins.
Buxton, L. F. (1969). An investigation of sex and age
differences in speech behavior under delayed auditory
134

135
feedback (Doctoral dissertation, Ohio State University,
1969). Dissertation Abstracts International. 30.
(4-B), 1939.
Calvert, D. R. (1982). Articulation and hearing
impairment. In N. J. Lass, L. V. McReynolds, J. L.
Nothern, & D. E. Yoder (Eds.), Speech, language, and
hearing: Pathologies of speech and language (Vol. II)
(pp. 638-651). Philadelphia: W. S. Saunders.
Calvert, D. R., & Silverman, S. R. (1983). Speech and
deafness: A text for learning and teaching.
Washington, D.C.: Alexander Graham Bell Association
for the Deaf.
Chouard, C. H., Fugain, B. M., & Lacombe, H. (1983). Long¬
term results of the multichannel cochlear implant.
Annals New York Academy of Sciences. 405, 387-411.
Clark, G. M. (1986). The University of Melbourne/Cochlear
Corporation (Nucleus) Program. In T. J. Balkany (Ed.)
The otolaryngologic clinics of North America. 19(2),
329-354.
Cohen, J. (1977). Statistical power analysis for the
behavioral sciences (rev. ed.) (pp. 9-12, 19-42). New
York: Academic Press, Inc.
Cowie, R. I. D., Douglas-Cowie, E., & Kerr, A. G. (1982).
A study of speech deterioration in post-lingually
deafened adults. The Journal of Laryngology and
Otology. 96/ 101-112.
Cowie, R. I. D., & Douglas-Cowie, E. (1983). Speech
production in profound postlingual deafness. In M. E.
Lutman & M. P. Haggard (Eds.), Hearing Science and
Hearing Disorders (pp. 183-230). New York: Academic
Press.
Daniloff, R. G., & Moll, K. L. (1968). Coarticulation of
lip rounding. Journal of Speech and Hearing Research,
11, 707-721.
Dew, D., & Jensen, P. J. (1977). Phonetic processing: The
dynamics of speech. Columbus, Ohio: Charles E.
Merrill.
Dew, D., & Jensen, P. J. (1979). Phonetic transcription:
An audito-tutorial program. 2nd Ed. Columbus, Ohio:
Charles E. Merrill.

136
Dorman, M. F., Dankowsik, K., McCandless, G. , & Smith, L.
(1989). Identification of synthetic vowels by patients
using the Symbion cochlear implant. Ear and Hearing.
10, 288-291.
Dowell, R. C., Seligman, B. E., Blarney, P. J., & Clark, G.
M. (1987). Speech perception using a two-formant 22-
electrode cochlear prosthesis in quiet and noise. Acta
Otolaryngol. 104. 439-446.
Eddington, D. K. (1988, May). Comparison of single-channel
and multiple-channel implants. In R. I Kohut (Chair),
Cochlear Implants. NIH Consensus Development
Conference. Washington, D.C.
Eguchi, S., & Hirsh, I. J. (1969). Development of speech
sounds in children. Acta Otolaryngol.. (Suppl. 257),
1-51.
Eisenberg, L. S., Berliner, K. I., House, W. F., & Edgerton,
B. J. (1983). Status of the adults' and children's
cochlear implant programs at the House Ear Institute.
Annals of the New York Academy of Sciences. 405. 323-
331.
Engelmann, L. R., Waterfall, M. K., & Hough, J. V. D.
(1981). Results following cochlear implantation and
rehabilitation. The Laryngoscope. 91, 1821-1833.
Evans, E. F. (1983). Pathophysiology of the peripheral
hearing mechanism. In M. E. Lutman & M. P. Haggard
(Eds.), Hearing Science and Hearing Disorders (pp. 61-
80). New York: Academic Press.
Fairbanks, G. (1954). Systematic research in experimental
phonetics: 1. A theory of the speech mechanism as a
servosystem. Journal of Speech and Hearing Disorders.
19, 133-139.
Fairbanks, G. (1955). Selective vocal effects of delayed
auditory feedback. Journal of Speech and Hearing
Disorders. 20, 333-346.
Fairbanks, F., & Guttman, N. (1958). Effects of delayed
auditory feedback upon articulation. Journal of Speech
and Hearing Research. 1, 12-22.
Fourcin, A. J., Douek, E. E., Moore, B. C. J., Rosen, S.,
Walliker, J. R., Howard, D. M., Abberton, E., &
Frampton, S. (1983). Speech perception with
promontory stimulation. Annals of the New York Academy
of Sciences. 405. 280-294.

137
Fravel, R. P. (1986). Cochlear implant electronics made
simple. The Otolaryngologic Clinics of North America.
Ü, (2), 11-22.
Gay, T. (1970). A perceptual study of American English
diphthongs. Language and Speech. 13. 65-88.
Gibson, W. P. R. (1987). Cochlear implants. In A. E. Keer
and J. Groves (Eds.), Scott-Brown's otolaryngology (5th
ed.) (pp. 602-617). Boston: Butterworths.
Goehl, H., & Kaufman, D. K. (1984). Do the effects of
adventitious deafness include disordered speech?
Journal of Speech and Hearing Disorders. 49., 58-64.
Gold, T. (1980). Speech production in hearing-impaired
children. Journal of Communication Disorders. 13. 397-
418.
Goldstein, M. O., & Friedelwald, W. T. (1988). Cochlear
implants. National Institutes of Health Consensus
Development Conference Statement, 7, (2), 1-9.
Harrington, J. (1988). Stuttering, delayed auditory
feedback, and linguistic rhythm. Journal of Speech and
Hearing Research. 31. 36-47.
Healey, W. C., Ackerman, B. L., Chappell, C. R., Perrin, K.
L., & Stormer, J. (1981). The prevalence of
communicative disorders: A review of the literature.
(Final Report) Rockville, Maryland: American Speech-
Language-Hearing Association.
Hegde, M. (1987). Clinical research in communicative
disorders: Principles and strategies (pp. 196-197).
Boston: College-Hill Press.
Holmes, A. E., Kemker, F. J., & Merwin, G. E. (1987). The
effects of varying the number of cochlear implant
electrodes on speech perception. American Journal of
Otology. 8, 240-246.
Hopkins, N. T. (Chair). Report of thead hoc committee on
cochlear implants. ASHA. 2.8 (4) , 29-52.
House, W. F. (1976). Cochlear implants. Annals of
Otolaryngology. Rhinologv and Laryngology. 85 (Suppl.
27), 1-93.
Huck, S. W., Cormier, W.H., & Bounds, W.G., Jr. (1974).
Reading Statistics and Research (pp. 196-221). New
York: Harper & Row.

138
Hudgins, C. V., & Numbers, F. C. (1942). An investigation
of intelligibility of speech of the deaf. Genetic
Psychology Monographs. 25. 289-392.
Humes, L. E., & Bess, F. H. (1981). Tutorial on the
potential deterioration in hearing due to hearing aid
usage. Journal of Speech and Hearing Research. 24.(1) ,
3-15.
Kessler, D. K. (1989). Present status of cochlear implants
in children. In E. Owens & D. K. Kessler (Eds.),
Cochlear Implants in Young Children (pp. 183-225).
Boston: A College-Hill Publication, Little, Brown and
Company.
Kirk, K. I., & Edgerton, B. J. (1983). The effects of
cochlear implant use on voice parameters. In I. K.
Arenberg (Ed.), The Otolaryngologic Clinics of North
America. 16, (1), 293-391.
Kuehn, D. P., & Moll, K. L. (1972). Perceptual effects of
forward coarticulation. Journal of Speech and Hearing
Research. 15. 654-664.
Lansing, C. R. (1988, May). Issues in aural
rehabilitation. In R. I. Kohut (Chair), Cochlear
Implants. NIH Consensus Development Conference.
Leder, S. B., Spitzer, J. B., Kirchner, J. C., Flevaris-
Phillips, C., Milner, P., & Richardson, F. (1986).
Speaking rate of adventitiously deaf male cochlear
implant candidates. Journal of the Acoustical Society
of America. 82 (3), 843-846.
Lee, B. S. (1950). Effects of delayed speech feedback.
The Journal of the Acoustical Society of America. 22.
824-826.
Levitt, H., McGarr, N. S., & Geffner, D. (1987). Language
and communication skills of young children. ASHA
Monographs. 26. Washington, D.C.: American Speech-
Language-Hearing Association.
Levitt, H., & Stromberg, H. (1983). Segmental
characteristics of the speech of hearing-impaired
children: Factors affecting intelligibility. In I.
Hochberg, H. Levitt, & M. J. Osberger (Eds.), Speech of
the Hearing-Impaired: Research. Training and Personal
Preparation, (pp. 53-73). Baltimore: University Park
Press.

139
Ling, D. & Ling, A. H. (1978). Aural hábilitation: The
foundations of verbal learning in hearing-impaired
children (pp. 54-76). Washington, D.C.: The Alexander
Graham Bell Association for the Deaf.
Lisker, L. & Abramson, A. D. (1964). A cross-language
study of voicing in initial stops: Acoustical
measurements. Word. 20, 384-422.
MacKay, D. G. (1968). Metamorphosis of a critical
internal: Age-linked changes in the delay in auditory
feedback that produces maximal disruption of speech.
The Acoustical Society of America. 43, 811-821.
MacKay, I. R. A. (1987). Phonetics: The science of speech
production. (2nd ed.), (pp. 61-152). Boston: A
College-Hill Publication, Little, Brown and Company.
Marascuilo, L. A., & McSweeney, M. (1977). Nonparametric
and distribution-free methods for the social sciences
(pp. 354-392). Monterey, California: Brooks/Cole
Publishing Co.
Martin, F. N. (1986). Introduction to audiology (3rd ed.),
Englewood Cliffs, NJ: Prentice-Hall.
Maxon, A. B., Brackett, D., Riordan, A., & Pfeffer, E. B.
(1987, November). Maximizing residual hearing;
Assessing and managing hearing-impaired children.
Paper presented at the meeting of the American Speech-
Language-Hearing Association, New Orleans, LA.
McGarr, N. S., & Harris, K. S. (1983). Articulatory
control in a deaf speaker. In I. Hochberg, H. Levitt,
M. J. Osberger (Eds.), Speech of the Hearing-Impaired
(pp. 75-95). Baltimore: University Park Press.
Medwetsky, L., Hanin, L., & Boothroyd, A. C. (1987).
Objective changes in the speech of cochlear implantees.
Paper presented at the annual convention of American
Speech-Language-Hearing Association. New Orleans, LA.
Miller, G. A., & Niceley, P. E. (1955). An analysis of
perceptual confusions among some English consonants.
Journal of the American Acoustical Society. 27. 338-
352.
Mimes, M. A., Hanson, B. F., & Shoup, J. E. (1978).
Frequency of occurrence of phonemes in conversational
English. Language and Speech. 21, 221-235.

140
Monsen, R. B. (1978). Toward measuring how well hearing-
impaired children speak. Journal of Speech and Hearing
Research. 21, 197-219.
Monsen, R. B. (1983). General effects of deafness on
phonation and articulation. In I. Hichberg, H. Levitt
& M. J. Oisberger (Eds.), Speech of the Hearing-
Impaired (pp. 23-34). Baltimore: University Park
Press.
National Center for Health Statistics. (1982).
[Unpublished data from the 1980 National Health
Interview Survey].
Nicolosi, L., Harryman, E., & Kresheck, J. (1989).
Terminology of communication disorders: Speech-
lanauaqe-hearing (3rd ed.) (p. 154). Baltimore:
Williams and Wilkins.
O'Connor, J. D., Gerstman, L. J., Liberman, A. M., Delattre,
P. C., & Cooper, F. S. (1957). Acoustic cues for the
perception of initial /w,j,r/ in English. Word. 13,
22-43.
Oster, A. (1988). Changes in speech with use of an
implant. Quarterly Progress and Status Reports. 4,
Stockholm: Speech Transmission Laboratory, Royal
Institute of Technology.
Owens, E., Kessler, D. , Telleen, C., & Schubert, F. (1981) .
The Minimal Auditory Capabilities Battery. St. Louis:
Auditec.
Patrick, J. F., & Clark, G. M. (1991). The nucleus 22-
channel cochlear implant system. Ear and Hearing. 12
(4), 3S-9S.
Perkins, W. H., & Kent, R. D. (1986). Functional anatomy
of speech, language, and hearing: A primer (pp. 18-
33). San Diego, CA: College-Hill Press.
Plant, G. (1984). The effect of an acquired profound
hearing loss on speech production: A case study.
British Journal of Audiology. 18, 39-48.
Punch, J. (1983) . The prevalence of hearing impairment.
ASHA. 25(4),27.
Seyfried, D. N., Hutchinson, J. M., & Smith, L. L. (1989).
Language and speech of the hearing impaired. In R. L.

141
Schow & M. A. Nerbonne (Eds.)» Introduction to Aural
Rehabilitation (2nd ed.), (pp. 181-239). Austin, TX:
Pro-Ed.
Schriberg, L. D. (1986). Programs to examine phonetic and
phonologic evaluation records (PEPPER). Version 4.0
[Computer program]. Madison, Wisconsin: Software
Development and Distribution Center, University of
Wisconsin-Madison.
Schriberg, L. D., Kwiatkowski, J., & Hoffmann, K. (1984).
A procedure for phonetic transcription by consensus.
JSHR. 27, 456-465.
Simmons, F. B. (1966). Electrical stimulation of the
auditory nerve in man. Archives of Otolaryngology. 84.»
24-76.
Skinner, M. W. (1978). The hearing of speech during
language acquisition. The Otolaryngologic Clinics of
North America. 11(3), 631-650.
Skinner, M. W., Holden, L. K., Holden, T. A., Dowell, R. C.,
Seligman, P. M., Brimacombe, J. A., & Beiter, A. L.
(1991). Performance of post lingually deaf adults with
wearable speech processor (WSPIII) and mini speech
processor (MSP) of the Nucleus multi-electrode cochlear
implant. Ear and Hearing. 12.(1), 3-22.
Smith, C. R. (1975). Residual hearing and speech
production in deaf children. Journal of Speech and
Hearing Research. 18., 795-811.
Strange, W., Jenkins, J. J., & Johnson, T. L. (1983).
Dynamic specifications of coarticulated vowels.
Journal of the Acoustical Society of America. 74, 695-
705.
Studdert-Kennedy, M. (1974). Speech perception. Haskins
status report. SR-39/40, 1-52.
Tye-Murray, N., Lowder. M., & Tyler, R. S. (1990). Com¬
parison of the FOF2 and F0F1F2 processing strategies
for the Cochlear Corporation cochlear implant. Ear and
Hearing. 11 (3), 195-200.
Tye-Murray, N., & Tyler, R. S. (1989). Auditory consonant
and word recognition skills of cochlear implant users.
Ear and Hearing. 10. 292-298.

142
Waltzman, S., & Hochberg, I. (1990). Perception of speech
pattern contrasts using a multichannel cochlear input.
Ear and Hearing, 11, 50-55.
Yates, A. J. (1963). Delayed auditory feedback. Psycho¬
logical Bulletin. 60(3), 213-232.
Yost, W. A., & Nielsen, D. W. (1985). Fundamentals of
hearing: An introduction (pp. 92-93). New York:
Holt, Rinehart and Winston.
Zimmerman, G. , & Rettaliata, P. (1981). Articulatory
patterns of an adventitiously deaf speaker:
Implications for the role of auditory information in
speech production. Journal of Speech and Hearing
Research. 24. 169-178.

BIOGRAPHICAL SKETCH
Polly Shipp Grey was born January 25, 1941 in Austin,
Texas. She graduated from McLeod Infirmary School of
Nursing, Florence, South Carolina, in 1963. She was
employed as a nurse in this country and in Pakistan from
1963 to 1970. In the fall of 1970, she was accepted into
the College of Nursing at Loma Linda University, Loma Linda,
California. She received her Bachelor of Science degree in
nursing in June, 1973. Continuing her nursing career, she
worked as a public health nurse and pediatric nurse
practitioner from 1973 to 1979. She began her graduate
studies at the University of Florida in the fall of 1981 and
received a Master of Arts degree from the Department of
Speech in 1984. She was employed as an audiologist by the
The Florida School for the Deaf and the Blind in St.
Augustine, Florida during the academic year 1984-1985. In
the fall of 1985, she returned to the University of Florida
to pursue her doctoral studies. Upon completion of the
requirements for the Doctor of Philosophy degree, she
intends to continue her career in clinical audiology.
143

I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
L*L A—s
5atncia B. Kricds, Chaii
Patricia B. Kricds, Chairman
Professor of Communication Processes
and Disorders
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
Alice T. Dyson, C<^Chairman
Assistant Professbr of Communication
Processes and Disorders
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
iseplí Kemicer
Professor of Communication Processes
and Disorders
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
Alice E. Holmes
Associate Professor of Communication
Processes and Disorders

I certify that I have read thi s study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
This dissertation was submitted to the Graduate Faculty
of the Department of Communication Processes and Disorders
in the College of Liberal Arts and Sciences and to the
Graduate School and was accepted as partial fulfillment of
the requirements for the degree Doctor of Philosophy.
May 1992
Dean, Graduate School

UNIVERSITY OF FLORIDA
3 1262 08554 2008



xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID EY0X4R9HI_O8YC77 INGEST_TIME 2017-07-11T21:54:40Z PACKAGE AA00002088_00001
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES