The role of the temporomandibular joint in mediating perception of mandibular position

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The role of the temporomandibular joint in mediating perception of mandibular position
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xi, 157 leaves : ill. ; 28 cm.
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Riski, John Edward, 1948-
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Mandible   ( lcsh )
Temporomandibular joint   ( lcsh )
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Thesis--University of Florida.
Bibliography:
Includes bibliographical references (leaves 150-156).
Statement of Responsibility:
by John Edward Riski.
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Typescript.
General Note:
Vita.

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THE ROLE OF THE

TEMPOROMANDIBULAR JOINT

IN MEDIATING PERCEPTION

OF MANDIBULAR POSITION



by



JOHN EDWARD RISKI


A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF

THE UNIVERSITY OF FLORIDA

IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE

DEGREE OF DOCTOR OF PHILOSOPHY



UNIVERSITY OF FLORIDA

1976














ACKNOWLEDGEMENTS


The author wishes to extend his sincerest gratitude

to his committee members, Drs. Ed Hutchinson, Bill Williams,

Chick LaPointe, and Parker Mahan. Throughout the project

they provided continued encouragement and assistance.

Acknowledgement is extended also to Dr. Joe Meier and

Mr. Harry Canter of Millersville State College, Millersville,

Pennsylvania and to Dr. Paul Ross, Franklin and Marshall

College, Lancaster, Pennsylvania. These gentlemen were

instrumental in completing the statistical analysis of the

data.

Finally, the author wishes to acknowledge the assist-

ance of Linda McCullers, who aided in all stages of the

study. It is to Linda that this study is dedicated.















TABLE OF CONTENTS

PAGE

ACKNOWLEDGEMENTS..........................................ii

LIST OF TABLES.............................................. v

LIST OF FIGURES........................................... viii

ABSTRACT................................................... ix


CHAPTER

ONE INTRODUCTION....................................1

Anatomy and Physiology...........................2

Review of Literature........................... 19


TWO STATEMENT OF PROBLEM........................... 38

Statement of Purpose........................... 39

Specific Objectives............................. 39


THREE METHODS AND PROCEDURES.........................41

Subject Selection.............................. 41

Experimental Tasks ............................. 41

Experimental Procedures.........................51

Filming Procedures..............................54

Procedures for Data Collection .................55


FOUR RESULTS.........................................65

Analysis of Perceptual Tasks and Connected
Speech .........................................65

Analysis of Speech Tasks and Nonspeech
Oral Movements.................................86

iii









TABLE OF CONTENTS continued

CHAPTER PAGE

FIVE DISCUSSION....................................106

Anesthetization of the Auriculotemporal
Nerve .................................... 107

Effect of Pressure............................. 114

Conclusions ...................................120


APPENDIX.................................................123

BIBLIOGRAPHY .............................................150

BIOGRAPHICAL SKETCH...................................... 157














LIST OF TABLES

Table Page

1 Individual Performance Scores and Group Means,
Ranges, and S.D.'s for Duplication of Interdental
Space Task: Range of Jaw Position for Ten Trials...66

2 Individual Performance Scores and Group Means,
Ranges, and S.D.'s for Duplication of Interdental
Space Task: Mean Difference of Jaw Position from
the Standard..................................... 68

3 Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Interdental
Thickness Discrimination ........................... 70

4 Mean Percent of Correct Subject Responses per
Stimulus Pair on a Measure of Interdental
Thickness Discrimination .......................... 71

5 Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Lateral Jaw
Position Discrimination to the Left................73

6 Mean Percent of Correct Subject Responses per
Stimulus Pair on a Measure of Discrimination
of Lateral Jaw Position Discrimination to the
Left ............................................. 74

7 Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Lateral Jaw
Position Discrimination to the Right.............. 75

8 Mean Percent of Correct Subject Responses per
Stimulus Pair on a Measure of Discrimination
of Lateral Jaw Position Discrimination to the
Right ............................................. 76

9 Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Anterior-Posterior
Jaw Position Discrimination ........................78

10 Mean Percent of Correct Subject Responses per
Stimulus Pair on a Measure of Discrimination of
Anterior-Posterior Jaw Positions....................79

11 Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Interdental
Weight Discrimination..............................80
v








LIST OF TABLES CONTINUED

Table Page

12 Results of Newman Keuls Analysis: Condition
Pairs for Measures of Tongue Tip Elevation.........88

13 Results of Newman Keuls Analysis: Condition
Pairs for Measures of Tongue Dorsum Elevation......91

14 Results of Newman Keuls Analysis: Condition
Pairs for Measures of Diphthong Production:
/o I/ .............................................. 93
15 Results of Newman Keuls Analysis: Condition
Pairs for Measures of Diphthong Production:
/eI/ ................ ............................ 94

16 Results of Newman Keuls Analysis: Condition
Pairs for Measures of Diphthong Production:
/aU/.............................................. 96

17 Results of Newman Keuls Analysis: Condition
Pairs for Measures of Diphthong Production:
/ I/ ...............................................97
18 Results of Newman Keuls Analysis: Condition
Pairs for Vowel-Consonant-Vowel Production:
/isi/ ............................................. 99

19 Results of Newman Keuls Analysis: Condition
Pairs for Vowel-Consonant-Vowel Production:
/asa,/ .......... .................................. 101

20 Results of Newman Keuls Analysis: Condition
Pairs for Vowel-Consonant-Vowel Production:
/iki/ .............................................103
21 Results of Newman Keuls Analysis: Condition
Pairs for Vowel-Consonant-Vowel Production:
/ -ka/ ........................ ................... 104

22 The Amount of Jaw Opening (in mm) for the
Initiation of Each of Ten Tasks Under the
Normal and Pressure Conditions................... 118
23 Elevate Tongue Tip............................... 124

24 Elevate Tongue Dorsum.................. .......... 127

25 Diphthong /aI/.................................... 130

26 Diphthong /eI/.................................... 132

27 Diphthong /aU/.................................. 134








LIST OF TABLES CONTINUED


Table Page

28 Diphthong /DI/..................................... 136

29 Vowel-Consonant-Vowel /isi/........................138

30 Vowel-Consonant-Vowel /a-soc /...................... 141

31 Vowel-Consonant-Vowel /iki/ ........................144

32 Vowel-Consonant-Vowel /a~k./ ....................... 147














LIST OF FIGURES
FIGURE PAGE

I Mandible: Left Lateral Aspect ................... ..5

2 Mandible: Left Medial Aspect......................7

3 Muscular Control of Mandibular Movement........... 10

4 Temporomandibular Articulation: Sagittal View....13

5 Temporomandibular Articulation: Frontal View.....14

6 Temporomandibular Ligament: Lateral View..........17

7 Sphenomandibular and Stylomandibular Ligaments:
Medial View................................... 18

8 Acrylic Blocks for Assessing Interdental
Thickness Discrimination......................... 44

9 Devices for Assessing Anterior-Posterior and
Lateral Mandibular Placement Discrimination......45

10 Weighted Acrylic Capsules for Assessing
Interdental Weight Discrimination ...............48

11 Cephalostat and Pressure Device.................53

12 Defined Measurements and Their Associated
Positive and Negative Values.....................57

13 Means, Ranges, and S.D.'s of Vertical Jaw
Positions Under Three Conditions for 17
Sounds Selected From a Connected Speech
Sample (N = 4)................................. 83

14 Means, Ranges, and S.D.'s of Horizontal Jaw
Positions Under Three Conditions for 17
Sounds Selected From a Connected Speech
Sample (N = 4)...................................85














Abstract of Dissertation Presented to the Graduate Council of
the University of Florida
in Partial Fulfillment of the Requirements for the Degree of
Doctor of Philosophy




THE ROLE OF THE
TEMPOROMANDIBULAR JOINT
IN MEDIATING PERCEPTION
OF MANDIBULAR POSITION

by

John Edward Riski

August, 1976



Chairman: Edward C. Hutchinson

Cochairman: William N. Williams

Major Department: Speech


Measures of mandibular positioning and movement are

described for a series of selected speech and nonspeech tasks

under normal and experimental conditions. The purpose of the

study was to evaluate the role of the sensory mechanism of the

temporomandibular joint in mediating perception of mandibular

position by 1) measurement of the positioning of the mandible

during selected speech and nonspeech tasks following unilateral

auriculotemporal nerve block and 2) measurement of the position-

ing of the mandible during selected speech and nonspeech tasks

during the application of a light pressure to the contralateral

temporomandibular joint capsule.

ix








Four young adult males, with normal occlusion and no

history of temporomandibular joint dysfunction, served as sub-

jects. Each subject completed all of the tasks under a nor-

mal condition, anesthetization of the right auriculotemporal

nerve, and anesthesia with a light pressure (one to two

pounds per square inch) applied to the left temporomandibular

joint capsule.

Each subject completed tasks designed to test his abil-

ity to perceive the position of his mandible in the superior-

inferior, lateral-medial, and anterior-posterior dimensions and

discriminate differences in weights of capsules held between

the teeth. In addition, each performed a series of tasks re-

quiring speech sound production and tongue elevation. The

anesthetization procedure utilized in this study did not appear

to disrupt subjects' perception of mandibular position for

any of the tasks in or significantly alter the positioning

of the mandible for the speech sample used. However, the

application of pressure disrupted subjects' ability to dis-

criminate between pairs of jaw positions to the right of

midline. Further, the application of pressure significantly

reduced the amount of jaw opening when the jaw opening was

observed to be greater than ten millimeters for the normal

condition.

The results of this study were interpreted to suggest

that the sensory mechanism of the temporomandibular joint, at

least the auriculotemporal nerve, has a minimal role in re-

gulating the positioning and movement of the mandible.









Further, these data suggested that pressure to the TMJ, on

the order of one to two pounds per square inch, inhibits the

translator motion of the condyle process.













CHAPTER ONE
INTRODUCTION


The oral structures primarily responsible for normal

speech articulation include the lips, tongue, velum, teeth,

and mandible. Considerable information is available rela-

tive to the normal placement and posture of these structures

for the production of normal speech elements. In addition,

several studies have demonstrated that there are identifiable

alterations in the speech signal following experimental

anesthetization of the oral structures (McCroskey, 1958;

McCroskey et al., 1959; Ringel and Steer, 1963; Schliesser

and Coleman, 1968; Gammon et al., 1971; and Scott and Ringel,

1971a).

Further, a growing body of literature exists which deals

with the assessment of mandibular function. Specific varia-

tions in mandibular placement have been observed for the pro-

duction of certain speech sound elements (Kent and Moll, 1972

and Owens, 1973). The independent, yet complimentary, actions

of the tongue and the mandible and the lower lip and the man-

dible have been recently described (Kent, 1972 and Sussman

et al., 1973). Other studies have demonstrated that subjects'

ability to perceive mandibular position for nonspeech tasks

is disrupted by anesthetization of the temporomandibular joint

(TMJ) capsule (Thilander, 1961). It has been reported also

that disruption in the perception of mandibular position,








caused by unilateral anesthetization of the TMJ capsule, can

be normalized by applying a painless pressure to the contra-

lateral capsule (Larsson and Thilander, 1964). A review of the

literature has failed to reveal any further information rela-

tive to the influence of anesthetization of the TMJ on the

control of mandibular position during speech function.

Therefore, the purpose of this study is basically

twofold: 1) to determine the effect of unilateral anestheti-

zation of the TMJ on normal subjects' ability to position the

mandible during selected speech and nonspeech tasks and

2) to determine the effect of a painless pressure administered

to the TMJ contralateral to the one anesthetized on subjects'

ability to position the mandible during the same selected

speech and nonspeech tasks.


Anatomy and Physiology


The mandible, or lower jaw, is comprised of a horizontal

portion, the body, and two vertical portions, the rami. The

rami unite inferiorly with the ends of the body. Superiorly,

the rami articulate with the temporal bone by way of the TMJ.

The complex movements of the mandible are made possible by

two groups of muscles, the muscles of mastication and the

suprahyoid muscles, and by the intricate function of the TMJ'S.

The purpose of this discussion is to describe the anatomy and

the physiology of the mandibular complex including the mandible,

the muscles that influence its movement and mandibular articu-

lation with the skull. The following account relies primarily

on the description of Enlow (1971), Gray (1959), Mahan (1967),









Sicher and DuBrul (1970), and Zemlin (1968).


Mandible: Origin and Growth

The body of the mandible is horseshoe shaped and ex-

tends upward and backward on both sides into the mandibular

ramus. The ramus extends upwards from the mandibular angle

and ends in two processes, the anterior, muscular coronoid

process and the posterior, articular condylar process. The

mandible is formed embryologically from the first branchial

arch, which is known also as the mandibular arch. The first

arch ultimately gives rise to the lower lip, the muscles of

mastication, the mandible, the anterior portion of the tongue,

and some of the middle ear structures. The mandibular arch

is joined with the maxillary processes at the extreme lateral

and rostral margins. The progressive anterior fusion between

these two processes reduces the width of the primative oral

fissure and forms the cheeks. At birth, the mandible is di-

vided into halves. It contains the alveoli for the deciduous

dentition. The angle of the ramus with the mandibular plane

is obtuse, about 170 Shortly after birth, the two halves

of the mandible become fused at the symphysis, beginning from

below. Fusion is usually complete by the first year. With

growth, the angle of the mandible becomes less and less obtuse.

At four years of age, it is about 140 and in the adult man-

dible, the angle is about 110* -120 .

The growing mandible enlarges in a forward and downward

manner with respect to the cranial base. However, the actual

course of growth proceeds in a complex process of bone








deposition and resorption predominantly in the posterior

and superior direction. The overall growth of the mandible

is associated with regional growth areas, which include

virtually all of the inner and outer surfaces of the mandi-

ble. These areas of growth include the neck of the condyle,

the coronoid process, the lingual tuberosity, the trihedral

eminence, and the chin. The regional growth movements are

concerned with a continuous process of relocation in which

the various local parts become shifted progressively in order

to maintain constant positions relative to the remainder of

the growing enlarging mandible as a whole.

Adult Mandible

As noted earlier, the mandible consists of a horseshoe

shaped body, which continues upward and backward into the

mandibular ramus. The ramus ends in two processes, the con-

dylar and the coronoid. Figures 1 and 2 illustrate the lat-

eral and medial aspects respectively of the adult mandible.

The mental symphysis joins the left and right mandibu-

lar bodies. Externally, it appears as a faint ridge. The

ridge divides inferiorly and encloses a triangular eminence,

the mental protuberance, which is depressed in the center,

but is raised on either side to form the mental tubercles.

The incisive fossa are the depressions lateral to the sym-

physis and just below the incisor teeth. The incisive fossa

are the origin of the mentalis and a small portion of the

orbicularis oris muscles. The mental foramen is found below

the second premolar tooth, midway between the inferior and


























,-'





. .. ; ... .,,<,


Body

Mental Protuberance

Mental Foramen

Oblique Line

9. Mandibular


5. Alveolar Process

6. Ramus

7. Condylar Process

8. Coronoid Process
Notch


Figure 1
Mandible: Left Lateral Aspect








superior borders of the body. The mental vessels and nerve

exit at the foramen. The oblique line is the faint ridge,

which proceeds posteriorly and superiorly from the mental

foramen becoming continuous with the anterior border of the

ramus. It provides attachments for the quadratus labii

inferior and triangularis; the platysma attaches just infer-

ior to the oblique line. The superior surface of the man-

dibular body is the tooth-bearing alveolar process. It is

hollowed into numerous cavities alveolii) for the reception

of teeth. The alveolar process resorbs with tooth loss re-

sulting in a reduced vertical dimension of the mandible.

The ramus of the mandible is directed superiorly from

the posterior portion of the body of the mandible. The ramus

divides superiorly into the condylar and the coronoid pro-

cesses. These processes are separated by the mandibular or

the semilunar notch. The anterior, coronoid process serves

as the point of attachment for the temporalis muscle. The

condyloid process frames the mandibular head, which articu-

lates with the mandibular fossa of the temporal bone by way

of the TMJ. The lateral surface of the ramus gives attach-

ment to the masseter muscle throughout nearly its whole ex-

tent.

The medial aspect of the mandible is illustrated in

Figure 2. Two small posteriorly directed spines are pro-

jected near the symphysis. These ridges or mental spines

are placed one above the other and serve as the origin for

the genioglossus muscle. The geniohyoid muscle originates

just inferior to the mental spines. Inferior and lateral to

the mental spines are the attachments for the anterior belly













































1. Mental Spines 3. Mandibular Foramen

2. Mylohyoid Line 4. Mylohyoid Groove

5. Angle of Mandible


Figure 2
Mandible: Left Medial Aspect








of the digastricus. The mylohyoid line extends posteriorly

and superiorly from the interior part of the symphysis. The

mylohyoid originates along this line. The superior pharyn-

geal constrictor originates, in part, from the posterior por-

tion of the line near the alveolar margin.

The medial surface of the ramus is marked near its

center by the mandibular foramen for the entrance of the in-

ferior alveolar vessels and nerve. The mylohyoid groove

runs obliquely inferiorly and anteriorly from the foramen

and houses the mylohyoid vessels and nerve. The angle of

the mandible provides attachments for the masseter laterally

and the internal pterygoid on its medial aspect. The internal

aspect of the ramus also provides attachments for several

ligaments. The attachments and ligaments will be discussed

later as a group.

Mandibular Musculature

The mandible is influenced in its movements and posi-

tioning by all of the muscles that attach to it. Further-

more, all mandibular muscles are active in all movements of

the mandible as their roles shift from movers to balancers

to holders (Sarnat, 1964). Two groups of muscles are of

prime concern. They are the muscles of mastication and the

suprahyoid muscles. Two other group of muscles are of se-

condary importance. They are the infrahyoid muscles, which

serve to stabilize the hyoid bone and the cervical column

and the post vertebral muscles, which serve to stabilize the

cranium, (Sicher and DuBrul, 1970 and Perry, 1973). The









focus of this discussion will be the two primary muscle

groups. The mandibular musculature can be divided by func-

tion or by muscles groups. For the purpose of this discus-

sion the musculature will be considered in muscle groups.

The direction of mandibular movement by each of the muscles

is illustrated in Figure 3.


Muscles of Mastication

Masseter. This muscle originates along the zygomatic

arch and zygomatic process and inserts along the ramus, the

coronoid process and the angle of the mandible. It is in-

nervated by the mandibular branch of the Trigeminal nerve and

serves to elevate the mandible.

Temporalis. This muscle has its origin on the floor of

the temporal fossa and the temporal facia. It inserts along

the anterior border of the coronoid process and the anterior

border of the ramus of the mandible. It is also innervated

by the mandibular branch of the Trigeminal nerve. It func-

tions to elevate and retract the mandible.

External Pterygoid (Lateral). This muscle originates

from the greater wing of the sphenoid and the lateral sur-

face of the lateral pterygoid plate. It inserts on the

anterior portion of the neck of the condylar process and the

meniscus of the mandibular joint. It is innervated by the

mandibular branch of Trigeminal nerve and serves to protrude

the mandible and pull the articular disc anteriorly. It

also assists in the rotary movement of the mandible for

chewing.











































Muscles of Mastication

M: Masseter

Te: Temporalis

EPy: External Pterygoid

IPy: Internal Pterygoid


Suprahyoid Muscles

Mh: Mylohyoid

Gh: Geniohyoid

Dab: Anterior Belly
of Digastric


Figure 3
Muscular Control of Mandibular Movement
After Cole (1971)








Internal Pterygoid (Medial). The origin of this muscle

is along the lateral pterygoid plate and the perpendicular

plate of the palatine bone. Insertion into the mandible is

along the posterior medial surface of the ramus and the

angle of the mandible, and innervation is from the mandibu-

lar branch of the Trigeminal nerve. It serves to protrude

and to elevate the mandible and also assists in the rotary

movement for chewing.


Suprahyoid Muscles

Mylohyoid. This muscle originates along the mylohyoid

line of the mandible and inserts along the median raphe from

the chin to the hyoid bone. It is innervated by the mylo-

hyoid branch of the Trigeminal. It elevates the hyoid bone

and the base of the tongue, but also assists in depressing

the mandible.

Geniohyoid. The mental spine of the mandible is the

origin of this muscle. It inserts on the body of the hyoid

bone and is innervated by the first and second cervical

nerves through the Hypoglossal nerve. It functions to ele-

vate the hyoid bone and move it anteriorly as well as to de-

press the mandible.

Digastricus (anterior belly). The anterior belly of

the Digastricus originates from the inner surface of the

mandible near the symphysis. It inserts into the inter-

mediate tendon of the hyoid bone. It is innervated by the

mylohyoid branch of the Trigeminal nerve. It also serves

to elevate the hyoid bone and to depress the mandible.








Temporomandibular Articulation

The TMJ is unique among all the joints of the human

body. It is a gynglmoarthrodial (sliding hinge) joint.

Unlike most articulating surfaces, the TMJ is not covered

by hyaline cartilage, but rather, is covered by an avascu-

lar, fibrous protein, collagen. Also unique to the TMJ

articulation is the fact that the two articulating complexes

house teeth, whose shape and position guide the joint when

teeth come to occlusion. Finally, the bilateral articula-

tion with the skull restricts certain mandibular motions,

such as lateral movement. The sliding and hinge movement

of the TMJ is possible because of an articular disc or

meniscus interposed between the temporal bone and the con-

dylar process of the mandible, thus dividing the articular

space into an upper and a lower compartment. Figure 4

illustrates a sagittal section of the TMJ articulation. The

hinge or rotational movement occurs between the condyle and

articular disc while the sliding or translational movement

occurs between the temporal bone and the meniscus.

The articular disc is a thin oval plate with tight

lateral and medial attachments to the condyle, an elastic

posterior attachment to the tympanic plate of the temporal

bone and an anterior attachment to the articular capsule

and to the lateral pterygoid muscle. The shape of the disc

is such that it accommodates itself with the surface of the

condylar process below and temporal bone above.

The TMJ is surrounded by a thin articular capsule,

which is illustrated in Figure 5. The capsule is loosely





















44 .-., /'.._ .-






















1. Mandibular Condyle 4. Upper Synovial Cavity

2. Articular Disc (Meniscus)5. Lower Synovial Cavity

3. Temporal Bone 6. Mandibular Fossa

7. Articular Eminence


Figure 4
Temporomandibular Articulation: Sagittal View
























*Li Le


1. Articular Capsule

2. Mandibular Fossa

3. Condylar Process


Articular Disc (Meniscus)

Upper Synovial Cavity
Lower Synovial Cavity


Figure 5
Temporomandibular Articulation: Frontal View








attached to the articulatory surfaces of the mandibular

fossa and to the neck of the condylar process laterally,

medially, and anteriorly. The capsule thickens laterally

into the temporomandibular ligament which will be included

in the following discussion. Except for the thickening, the

capsule is loosely organized in its lateral aspect and the

lateral aspect of the anterior wall. The medial aspect of

the anterior wall has attachments to the articular disc and

to the lateral pterygoid muscle. The medial and posterior

walls of the capsule are present but also loosely organized.

In translational movements, the condyle is pulled anteriorly

onto the articular eminence. As the meniscus is tightly

attached to the condyle while having only an elastic attach-

ment posteriorly to the tympanic plate of the temporal bone,

the meniscus translates anteriorly with the condyle. How-

ever, the attachment of the meniscus to the condyle is not

rigid enough to prevent movement of the condyle against the

meniscus in a horizontal plane during hinge as rotary move-

ment of the mandible.

The first stage of mandibular depression is a simple

hinge action, and only the lower compartment is used as the

head of the condyle rotates along the inferior surface of

the articular disc. As the mandible is further depressed,

translation begins between the disc and the articular emi-

nence resulting in forward displacement of the condyle.

There are three ligaments which participate in TMJ

articulation. These ligaments are now believed to function

in limiting jaw movement at maximum open jaw positions and








to provide proprioceptive input to the central nervous

system via their Golgi tendon organs. These ligaments are

illustrated in Figures 6 and 7.

The temporomandibular ligament is comprised of two short

bundles, one anterior to the other. As noted earlier, this

ligament is a thickened portion of the articular capsule. The

ligament is attached superiorly to the zygomatic arch and

inferiorly to the lateral, posterior surface of the condylar

process.

The sphenomandibular ligament is a remnant of Mechel's

cartilage. The ligament arises from the angular spine of the

sphenoid bone and spreads fanlike downward and outward

finally attaching to the mandible ar the lingula of the man-

dibular foramen.

Lastly, the stylomandibular ligament extends from near

the apex of the styloid process of the temporal bone to the

angle and posterior border of the ramus of the mandible.

Sensory innervation to the TMJ capsule is supplied

primarily by the auriculotemporal nerve of the mandibular

branch of the Trigeminal nerve. Small slips of the masseteric

and posterior deep temporal nerve also supply the capsule

anteriorly.

Histological studies have provided further information

regarding the sensory innervation of the capsule. Thilander

(1961) demonstrated that the posterior and lateral aspects

of the capsule are the most richly innervated, while the

anterior and medial aspects are sparsely innervated and the

articular disc lacks any sensory innervation. Thilander found



















V '


1. Temporomandibular Ligament
2. Capsular Ligament
(Articular Capsule)



Figure 6
Temporomandibular Ligament:


Zygomatic Arch
Condylar Process


Lateral View













































1. Sphenomandibular Ligament

2. Angular Spine of Sphenoid

3. Mandibular Foramen


4. Stylomandibular Ligament

5. Styloid Process

6. Angle of Mandible


Figure 7
Sphenomandibular and Stylomandibular Ligaments:
Medial View








four types of nerve endings in the capsule. Free nerve

endings were the most abundant. Organized endings such as

Ruffini endings, Golgi tendon organs, and the Vater-Pacini

corpuscles are represented, but only sparsely.

Investigations of the role of joint receptors in

perception of position sense and kinesthesis by Mountcastle

and Powell (1959) provide further information of the sensory

capabilities of the TMJ joint receptors. They identified

two types of slowly adapting nerve endings. These endings

discharged at a steady rate that was influenced only by the

angle of the joint. Individual receptors responded to arcs

of 15 to 20 degrees. Thus, they functioned as absolute

detectors of joint angle. The two groups of endings were

the spray type Ruffini endings and the Golgi tendon organs,

both of which are present in the TMJ.

The blood supply to the TMJ capsule is through the

superficial temporal and maxillary arteries posteriorly and

from the twigs of the masseteric artery anteriorly. The

articular disc, which is avascular in its center, has an

unusually rich plexus of veins on the periphery. The plexus

serves to equalize pressure in the tissues by filling and

emptying as the condyle rocks rythmically forward and back-

ward in chewing.



Review of Literature

The purpose of this review is to present the current

understanding of oral sensation and perception with specific

reference to mandibular kinesthesia. In addition, mandibular








function will be discussed in reference to the physiological

processes of mastication, deglutition, and speech.


Sensory Interruption

Fairbanks (1954) proposed a feedback loop theory of

speech production in which he hypothesized that tactile and

kinesthetic feedback, in addition to auditory feedback, are

necessary for normal speech production. The importance of

auditory feedback for speech production is supported by the

results of investigations which have demonstrated that de-

laying the air borne auditory signal (delayed auditory feed-

back) of normal speakers typically results in an aberrant

speech pattern characterized by dysfluency, general articu-

lation inaccuracy and modification of speech sound duration,

the fundamental frequency and the sound pressure level (Lee,

1950; Black, 1951; and Fairbanks, 1955). The need for tactile-

kinesthetic information has been supported by researchers who

have demonstrated that there is a relationship between oral-

sensory integrity and articulation proficiency (McCroskey,

1958; McCroskey et al., 1959; Ringel and Steer, 1963: Schliesser

and Coleman, 1968; Thompson, 1969; Gammon et al., 1971; Scott

and Ringel, 1971a; Scott and Ringel, 1971b; Horii et al., 1972;

and Borden, 1973).

The task of oral stereognosis, which involves the iden-

tification of plastic shapes presented intra-orally has evolved

recently as a possible indicator of oral sensory integrity.

Research has indicated that the subjects' performance








on this task, which has been suggested to involve intra-oral

movements similar to those in speech production, is severely

disrupted by mandibular block anesthesia (Schliesser and

Coleman, 1968 and Thompson, 1969).

A positive relationship between speech skills and oral

stereognosis has been established also (Moser et al., 1967;

Ringel et al., 1968; Weinberg 1970; Fucci and Robertson,

1971; and McNutt, 1973). These studies have demonstrated that

articulatory defective individuals without any known structural

or organic pathologies perform poorer on tasks of oral stere-

ognosis than do their normal speaking counterparts. Further

evidence of a positive relationship between speech skills and

oral stereognosis is offered by Bishop et al. (1973). These

researchers compared the performance of manually educated

deaf individuals and to normal hearing speakers on a task of

oral stereognosis. The experimental group made more errors

on this task as well as making different types of errors as

compared to the other two groups. The authors suggested that

orosensorimotor functions develop, in part, through the prac-

tice of speech skills.

A discussion of sensory disruption is necessarily

followed by a discussion of feedback systems. The researchers

who initially investigated articulation under nerve block

anesthesia assigned monitoring abilities for any uneffected

articulatory events to other channels, presumably undisturbed

by the anesthesia. This reflects the view that all articula-

tory activities are monitored by some sensory channel. This








view of a closed-loop feedback system was reported by

MacNeilage (1970) and Abbs and Netsell (1973).

Hixon and Hardy (1964), on the other hand, proposed

that speech movements were programmed. This view was

supported by Kent (1973) who found time intervals between

articulatory events were too short to accommodate the use of

feedback. Kent (1973) proposed that speech is more likely

operating under open-loop control or that speech is pre-

programmed centrally. He postulated that feedback might be

employed in a reset capacity to allow for occasional

adjustment of the motor program.

Although much of the discussion regarding feedback

control is theoretical, interpretation of current evidence

suggests that both closed-loop and open loop control systems

are actively involved in motor control of speech (Putnam

and Ringel, 1972 and Abbs, 1973). Thus, after a speech

sequence is triggered initially as a unit, peripheral sensory

mechanisms make fine adjustments. Such a theory may help

explain why only minor distortions of the speech signal are

observed when bilateral mandibular blocks are performed.


Mandibular Position Movement

The limited amount of research on mandibular positioning

can be attributed to the absence of convenient and accurate

transduction techniques. Geissler (1971) outlined three

requirements for instrumentation. It should be able to record

a large number of patients, should not interfere with normal

mandibular movements, and should allow continuous recording

during mandibular movement.








Within the past several years, a number of techniques

have been developed to record mandibular movement during a

variety of functions. The techniques include cinefluoro-

graphy (Jankelson et al., 1953), the Case Gnathic Replicator

(Gibbs et al., 1966), the Perspex screen (Atkinson and

Shepherd, 1955), Photoelectric Mandibulography (Gillings

and Graham, 1964), and strain gauge devices (Sussman and

Smith, 1970). There are advantages and disadvantages to each

method. Some provide information of only two planes of

movement (Photoelectric Mandibulography, cinefluorography,

and the perspex screen). Others are expensive to operate

(Case Gnathic Replicator) or appear to interfere with normal

mandibular movement (strain gauges). Nonetheless, with this

variety of instrumentation, an understanding of mandibular

movement is developing.

Several measurement strategies have been developed

recently to study mandibular kinesthesia. These techniques

include duplicating an interdental space (Thilander, 1961)

and several methods of assessing interdental space discrim-

ination (Ringel et al., 1967; Williams and LaPointe, 1972;

and Williams et al., 1974). As a result of available

instrumentation and test methodology, there is a growing

body of literature on assessment of mandibular function.

Researchers have begun to define quantitatively mandibular

kinesthesia and mandibular function for the biophysiological

processes of the mastication, deglutitipn, and speech. Initial

attempts also have been made to define the sensory mechanism

responsible for









neuromuscular control of mandibular movement and positioning

for these processes. The following literature review presents

the current understanding of mandibular kinesthesia and man-

dibular and TMJ function for the processes of deglutition,

mastication, and speech.


Mandibular kinesthesia

Oral kinesthesia has been defined by Ringel et al.

(1967) as the sense by which muscular motion, weight, and po-

sition of an oral structure is perceived. Rose and Mountcas-

tle (1959) previously established that intact joint receptors

and central nervous system relay networks are required for

kinesthesia. Mountcastle and Powell (1959) confirmed that

specific joint endings with cortical projections respond to

absolute degrees of arc or joint angles. Thus, defining

mandibular kinesthesia as the sense of perceiving the posi-

tion, motion, and weight of the mandibular structure appears

completely acceptable. Research indicates, however, that

Subjects' performance on tasks of interdental thickness dis-

crimination mandibularr position) is unrelated to their per-

formance on tasks of interdental weight discrimination and

that different receptors may be responsible for the percep-

tion of mandibular position and the interdental perception

of weight (Williams and LaPointe, 1972).

The study of mandibular kinesthesia in normal human

individuals has concentrated primarily on subjects' ability

to discriminate differences in mandibular positions. Although

instrumentation has varied, the results reported by various








investigators have been remarkably similar. Thilander (1961)

described a task which required subjects to choose a random

jaw position between the rest position and maximum jaw open

position and then to replicate that position ten times. Under

normal conditions, the subjects came within plus or minus

1.6 mm of duplicating this position over 20 trials. Ringel

et al. (1967) used a modified vernier-type caliper placed

between the biting surfaces of the upper and lower central

incisors. Their results indicated that absolute difference

limen values are relatively independent of the degree of

mouth opening. They reported an average difference limen of

2.04 mm. Williams and LaPointe (1972) and Williams et al.

(1974) used pairs of plastic blocks and pairs of plastic

wedges to attain difference limens. With the use of pairs

of plastic blocks, they reported an average difference limen

of 1.91 mm. They concluded also that interdental thickness

discrimination was independent of mouth opening. Williams

et al. (1974) used pairs of plastic wedges (the wedges

required quided mandibular motion to a given position), to

establish difference limens and reported an average difference

limen of 1.37 mm. They suggested that the lower difference

limen, using the wedges, reflected the mandibular movement

required by the instrumentation and provided subsequent

activation of additional sensory receptors in the TMJ.

Further understanding of the sensory mechanism of

mandibular kinesthesia has been gained from other studies

of interdental thickness discrimination. Originally, the








receptors responsible for mediating the sense of mandibular

position were thought to be housed in the TMJ capsule, muscles

of mastication, or possibly the periodontal ligament

(Thilander, 1961). Studies of interdental thickness discrim-

ination comparing the performance of dentulous and edentulous

subjects suggest that the periodontal ligament is not respon-

sible for perception of mandibular position (Manly et al., 1952;

Kawamura and Watanabe, 1960; Woodford, 1964; and Siirila and

Laine, 1963). Again, although instrumentation and methodology

differed slightly, several groups of researchers have reported

that the ability to detect thicknesses or difference in thick-

nesses does not differ appreciably between dentulous and

edentulous subjects. Discrimination of thickness appears

equally good between natural incisors and natural molars

(Kawamura and Watanabe, 1960 and Siirila and Laine, 1963).

Neither is there any significant difference in perception

threshold when both upper and lower antagonistic teeth are

anesthetized (Siirila and Laine, 1963), nor when the alveolar

mucosa is topically anesthetized (Manly et al., 1952).

Woodford (1964) found that edentulous subjects performed

equally as well on a task of thickness discrimination with or

without their dentures.

The TMJ's sensory mechanism has been implicated as

performing an active role in mandibular kinesthesia in re-

search by Thilander and her colleagues. Thilander (1961)

hypothesized that disrupting the sensory mechanism would impair

perception of mandibular position. She developed a task for








assessing mandibular kinesthesia which required subjects to

choose an arbitrary jaw position between mandibular rest

position and maximum opened jaw position and then attempt

to replicate that position ten times in close succession.

From the results of a series of experiments, including uni-

lateral and bilateral anesthetization of the TMJ capsules

and anesthetization of the inferior nerve, she concluded

that the TMJ capsule is responsible at least in part, for

mediating perception of mandibular position. More speci-

fically, subject performance varied from normal only under

conditions of unilateral and bilateral anesthetization of the

TMJ capsule. Subject performance was disrupted equally under

unilateral and bilateral anesthetization.

The findings of Larsson and Thilander (1964) prove

quite provocative. These researchers evaluated the effects

of certain "distracting" stimuli including stroboscopic light

flicker, sound stimulis (clicks), stimulation of the right

median nerve, painful pressure applied on the joint, and pain-

ful pressure applied anterior to the joint on subjects' abi-

lity to replicate arbitrary jaw position (Thilander, 1961).

The subjects performed significantly poorer than normal un-

der all conditions of "distracting" stimuli except when

painful pressure was applied to the joint. Performance under

this condition did not vary from normal. Further investiga-

tion of this phenomena revealed that a more moderate, pain-

less pressure could normalize the disruptive effects of any

of the "distracting" stimuli and even more remarkably, a








painless pressure could normalize the disruptive effects

of unilateral anesthetization of the TMJ capsule when the

pressure was administered to the contralateral joint capsule.

The authors theorized that the normalizing effect was the re-

sult of activation of nervous elements in the richly inner-

vated lateral aspect of the capsule. They also explained

that there may be alteration in the tension of the capsule

requiring less movement than normal to discharge receptors.

Thus, positional changes could be perceived more readily.

Ransjo and Thilander (1963) demonstrated that the func-

tion of the TMJ receptors is impaired in TMJ disorders

ascribed to malocclusion, but not dysfunctions of myogenic

origin. Storey (1968) interpreted these results as indi-

cating that the masticatory muscles are not involved in per-

ception of mandibular position. Ransjo and Thilander (1963)

reported also that in cases of unilateral TMJ dysfunction

again a painless pressure applied to either the intact joint

or both joints would normalize the perception of mandibular

position. The impaired perception of mandibular position in

the malocclusion group could also be normalized by adjusting

and correcting the malocclusion.

Finally, Posselt and Thilander (1965) studied the role

of the TMJ receptors in controlling border movements (extreme

positions) of the mandible. They reported significant in-

creases in maximum vertical jaw opening under conditions of

unilateral and bilateral anesthestization of the TMJ capsules.

They concluded that the TMJ ligaments participate not only in








mediating the perception of position, but also appear to act

as a protective mechanism during extreme open positions of

the mandible.

The evidence to date suggests that a subject's ability

to perceive and/or to discriminate between different mandi-

bular positions, as measured by tasks of interdental thickness

discrimination, is independent of the presence of natural

or artificial dentition. In addition, this ability also

appears to be independent of the sensory integrity of the an-

tagonistic teeth. However, there is strong evidence that the

nerve endings in the TMJ are responsible, at least in part,

for mediating perception of mandibular position.

More recently, Siirila and Laine (1972) presented the

results of a study designed to study the effect of anesthesia

of the TMJ capsule on subjects' ability to judge between dif-

ferences in mouth opening. These researchers used a modi-

fied caliper to establish the difference necessary to descrim-

inate mouth openings from a series of standard openings.

Subjects' performance under bilateral intracapsular TMJ

anesthesia was equivalent to their performance for the normal

condition. They concluded that different sensory mechanisms

might be involved in replicating a mouth opening (Thilander,

1961) and their task of size discrimination. However,

Siirila and Laine's (1972) test protocol allowed subjects

to tap their teeth against the test instrument. Tapping

very likely activated sensory endings in the periodontal

ligament and receptors in the TMJ that respond to movement.








Williams and LaPointe (1974), reported earlier, suggested that

smaller values of mouth opening may be discriminated when TMJ

movement is allowed.

Deglutition mastication

The process of deglutition and mastication have been

described narratively by Fletcher (1970 and 1971). Fletcher

(1970) described the role of the mandible in a mature

swallow as providing a stable base from which the oral

structures function as they collect a bolus and force it

posteriorly. A graphic description of mandibular movement

during mastication has been provided recently by Gibbs et al.

(1971) and Gibbs and Messerman (1972). Using the Case Gnathic

Replicator (Gibbs et al., 1966), they were able to record

graphically mandibular motion in three planes of movement.

Many of their comparisons of the mandibular masticatory

process were relative to mandibular movement for speech

function. For example, they found that the maximum vertical

opening for chewing was typically two to four times more than

the vertical opening for speech. The amount of vertical

opening during speech was relatively equal between subjects

while it varied considerably for chewing. Speech function

involved little lateral motion of the mandible whereas there

was a great deal of lateral movement during chewing. Hori-

zontal or anterior-posterior movement of the mandible appeared

equal for both processes, however, it was proportionately

greater in relationship to vertical movement for speech. There

was asymetrical motion of the condyles during mastication.








The working condyle, on the side with the food, reached the

maximum opening first. The mandible stopped movement during

chewing for a brief time at its closed stage. Condylar move-

ment was prominent in masticatory function, but not for speech.

Finally, the average maximum velocities for chewing were

considerably greater than for speech (6.05 in./sec. and 1.65

in./sec. respectively). Gibbs and Messerman (1972) concluded

that much important information concerning mandibular movement

for speech could be obtained from measuring the vertical and

horizontal motion exclusively.

Interest in mandibular movement for deglutition and the

masticatory process necessarily implies interest in the systems

neurocontrol mechanism. Ingervall et al. (1971) examined the

occlusal positions of the mandible and the movements of the

hyoid bone with and without anesthesia of the TMJ capsules.

These researchers reported that dental contact was common

during swallowing and could find no differences in positions

between swallowing prior to or during anesthetization. The

hyoid bone movement patterns were also independent of the

anesthesia condition.

Ingervall et al. (1972) utilized the films collected

earlier (Ingervall et al., 1971) and evaluated the influence

of the receptors in the TMJ capsules on the duration of

swallowing and movements of the hyoid bone. They reported

that bilateral anesthetization of the TMJ capsule had no effect

on the duration of the movement of the hyoid bone. This is not








too surprising since the swallow patterns include dental

occlusion and thus provided added feedback from the perio-

dontal ligament. In addition, there is no reason to suspect

that the temporomandibular articular receptors provide any

feedback which would influence the oral structures involved

in swallowing as they appear to be more active in conscious

positioning of the mandible and the mandible is already po-

sitioned at the iniation of the swallow sequence.

Several other researchers have explored the nature of

the control of the mandible for dynamic masticatory function

either directly or indirectly. Shepherd (1960) reported that

the total movement of the mandible decreased with age, use

of dentures, and introvert personality type. Denture wearers

demonstrated similar masticatory patterns with and without

their dentures, however, as might be expected, the amount of

vertical movement was much greater without dentures. The

masticatory pattern was also unchanged prior to and after

complete teeth extraction. However, abnormal masticatory

patterns were evident in individuals who demonstrated exces-

sive occlusal wear and who had pain, clicking, or other symp-

toms of TMJ dysfunction. The author reported that in no case

where the TMJ was showing abnormal symptoms was the associated

masticatory cycle considered to be normal. In many cases,

marked irregularities occurred in the patterns with a lack of

smoothness in individual cycles and sometimes there was a

complete lack of rythm from cycle to cycle.

These findings were supported by Atkinson and Shepherd

(1961). In one patient whose TMJ dysfunction was diagnosed








as resulting from malocclusion, the malocclusion was adjusted

with an appliance. The resulting masticatory movement was

found to be much smoother.

In a study reported by Schaerer et al. (1966), anesthesia

of the TMJ capsules and periodontal ligament did not effect

mandibular movements, muscle activity, or contact between teeth

during chewing. Thus, it appears that mandibular movement and

positioning during the processes of deglutition and mastication

in normal individuals is not disrupted by anesthetizing the

TMJ. However, abnormal masticatory patterns have been observed

in individuals who have demonstrated excessive occlusal wear

and have had pain, clicking, or other symptoms of TMJ dysfunc-

tion. This might suggest that long standing disruption of

TMJ function is necessary before there is observable altera-

tion in the masticatory stroke.


Speech function

The initial interest in mandibular movement and position

during speech appears to have been generated by researchers in

the field of prosthetic dentistry. Simple phonetic tests, such

as counting from one to ten or repeating /s/ loaded words,

hve been used to establish "closest speaking space" or closest

interdental space in the construction of clinically accepted

dentures (Geissler, 1971 and Gillings, 1973).

Recently, speech researchers have begun to measure

mandibular position for speech function while systematically

varying phonetic context. The results of the research from








these two areas is in close agreement and can be summarized

and discussed together. Another current investigation of

speech and masticatory function (Gibbs and Messerman, 1972)

has been discussed earlier and will not be included here.

There seems to be a general agreement among researchers

that jaw position is lower for vowel sounds (/a/,/2/), diph-

thongs (/al/), and back consonant (/k/,/g/) production and is

more elevated for high vowels (/i/,/u/) and front consonant

(/p/,/s/) production. The mandible has been observed to dis-

place posteriorly as it displaces inferiorly. Kent and Moll

(1972) and Owens (1973) have explained that this is due to

the hinge-type movements of the condyle for the mandible's

speech movements. It is also recognized that adjacent pho-

nemes may cause mandibular position to vary slightly for any

one phoneme. Geissler (1971) has demonstrated further that

mandibular movement may vary with speaking rate, becoming

less as speaking rate increases. Geissler (1971) and Gillings

(1973) have observed also that while mandibular position for

closed sounds tends to be fairly consistent from individual

to individual, the position of the mandible varies from in-

dividual to individual for open sounds. Although there is

obviously room for continued research in this area, it is

apparent that specific mandibular positions are responsible

for specific phonetic productions.

Other areas of mandibular dynamics are also currently
under investigation. New research is providing information

that is beginning to explain the complex interplay between

the dynamic mandible and other articulators including the lips








and the tongue. It is now obvious that the tongue does not

move in complete harmony with the mandible (Kent, 1972).

Kent (1972), who studied the relationship of tongue body and

mandibular movement during speech, concluded that the overall

displacements of the tongue body and jaw vary with phonetic

context. He also identified a "trading relationship" between

the tongue and the mandible; the smaller the amount of jaw

movement, the greater must be the extent of tongue motion.

Sussman et al. (1973) reported that although the jaw

and the lower lip are mechanically linked and constrained by

each other, they also act as independent articulators, each

reflecting their own specific movement characteristics. He

also reported that the less the jaw contributes to the forma-

tion of a bilabial stop, the higher the elevation of the lower

lip.

This independence in movement between jaw and tongue

and jaw and lip might be interpreted as evidence for separate,

yet interconnecting feedback systems where one system is

responsible for monitoring the other and compensating for it.

Further research of mandibular and tongue body dynamics

reveals similarities in the relationship of movement velocity

to displacement. That is, the greater the displacement of the

structure during speech, the greater the velocity of movement

(Abbs et al., 1972; Sussman et al., 1973; and Kent and Moll,

1972).

There is research in the literature that assists in

understanding the complex interplay between the mandible and








the other oral structures during speech. Hansen (1952)

studied speech intelligibility using single words under

varying conditions of jaw restriction from full restriction

to no restriction. He found no differences in intelligi-

bility among any of the conditions. This researcher noted,

however, that a speech sample simulating connected speech

might yield different results. These findings are in agree-

ment with those of Kent (1972), who reported the indepen-

dence of tongue and jaw dynamics and the apparent compensa-

tory action between the two.

Weiss (1969a) disrupted lingual and palatal action

in eleven year olds and reported that this disruption does

not significantly effect the acoustic parameters of articu-

lation. Weiss (1969b) evaluated the lingual-palatal and

mandibular placement of the subjects of his earlier study.

He discovered that the tongue tip placement for some phonetic

productions were disrupted, although there was no signifi-

cant overall disruption. However, he did report that there

was greater mandibular displacement after anesthesia for the

phonemes /1/ and /I/, two phonemes that seem to involve less

tactile feedback than most. Following anesthetization, there

was also greater variation in the physiologic rest position

of the mandible. Weiss (1969b) questioned whether disrupted

action of one structure in the articulatory system affects

the function of another in the same system.

Sussman and Smith (1971) monitored and recorded jaw

movements under varying degrees of DAF. They reported no








overall disruptive effects of DAF on jaw positioning nor on

the duration of the velocity of jaw movement. However, they

did find isolated instances of disruption. Although not

statistically significant, there seemed to be a trend for the

jaw to overshoot its position for some vowels under the 0.3

second delay condition. They also reported a significant in-

crease in the length of jaw activity for the 0.1 second delay

condition. These results offer some evidence that auditory

feedback may be important in controlling mandibular position.

Research on mandibular function for speech processes

has demonstrated the vertical and horizontal positioning is

dependent on the phonemic makeup of the speech sample.

Current research has provided information of the independent,

yet complimentary actions of the mandible and the tongue

during articulation. Investigators who have disrupted lingual

tactile and auditory feedback during speech have reported only

minimal and inconsistent alterations of mandibular position.














CHAPTER TWO
STATEMENT OF PROBLEM


The literature reviewed in CHAPTER ONE suggests that

experimental anesthetization of the oral structures results

in quantifiable alterations in subjects' performance on

oral-sensory-perceptual tasks as well as alteration of cer-

tain characteristics of speech production. The literature

reviewed has revealed also that mandibular position is spe-

cific for certain phonetic productions. In addition, these

studies reveal that the sensory mechanism within the TMJ

apparently controls, to some degree, the movement and posi-

tioning of the mandible. Moreover, it would appear that

measurement strategies, such as duplicating an interdental

space (Thilander, 1961) or interdental thickness discrimin-

ation (Williams and LaPointe, 1972 and Williams et al.,

1974) might be used in determining as index of sensory in-

tegrity of the TMJ. The literature reviewed has demonstrated

further that the effect of anesthetizing one TMJ can be nor-

malized by a painless pressure applied to the contralateral

capsule (Larsson and Thilander, 1964).

If anesthetization of the TMJ causes impairment in the

regulation and control of mandibular position, and if fine

sensory motor coordination of jaw placement and movement is,

in fact, critical for the production of normal speech sounds,








it seems reasonable to suggest that disruption of the TMJ

sensory system would have a demonstrable effect on the overall

articulatory pattern of the mandible for speech production.

It might be suggested also then that the application of

pressure to the unanesthetized TMJ might be expected to have

a normalizing effect on mandibular patterns of movement and

positions for speech. However, a review of literature has

failed to identify any investigation directly concerned with

the role of the TMJ sensory mechanism as related to the

regulation and control of mandibular movement and positioning

for speech sound production.


Statement of Purpose


Therefore, the purpose of this study is basically two-

fold: 1) to determine what effects occur with unilateral

anesthetization of the TMJ relative to the positioning and

movement patterns of the mandible during selected perceptual

tasks, nonspeech oral movements, and a selected speech sample

and 2) to determine what effects occur with a subsequent

administration of a painless pressure to the TMJ capsule

opposite the one anesthetized on the positioning and movement

patterns of the mandible during selected perceptual tasks,

nonspeech oral movements, and a selected speech sample.


Specific Objectives

A series of tasks was devised in an attempt to measure

the effect of the anesthesia and pressure on the positioning








of the mandible. All of the tasks were performed under the

two experimental conditions and under a normal, control

condition with no anesthesia and no pressure. The three

categories of tasks included: 1) four perceptual measures

of mandibular position discrimination and one perceptual

measure of interdental weight discrimination, 2) two tasks

requiring nonspeech oral movements, and 3) nine tasks

requiring speech sound production. Thus, there was a total

of sixteen separate tasks.

The specific objectives of the study were:

1) to compare subjects' performance on each of the

five perceptual tasks under the two experimental conditions

and the one control condition,

2) to compare subjects' performance on each of the

two tasks requiring nonspeech oral movements under the two

experimental conditions and one control condition, and

3) to compare subjects' performance on each of the

three tasks requiring speech sound production under the two

experimental condition and one control condition.














CHAPTER THREE
METHODS AND PROCEDURES



Subject Selection

Four young adult males served as subjects. Their ages

range from 22 years, 4 months to 29 years, 4 months with a

mean age of 25 years, 11 months. The individuals who served

as subjects possessed all of their natural central incisors,

had an Angle Class ONE occlusion with a normal bite. None of

the subjects complained of any current or past history of TMJ

dysfunction. All subjects were monolingual speakers of the

General American Dialect and had no articulation or voice

disorders.


Experimental Tasks


Perceptual Measures

The perceptual measures utilized in this study were de-

signed to assess subjects' abilities to discriminate between

differences in mandibular positions and to discriminate be-

tween differences in weights placed between the maxillary and

mandibular incisors. The first perceptual measure required

each subject to duplicate an arbitrary interdental space.

This task was included as an attempt to replicate and verify

Thilander's initial research in the area of TMJ anesthetiza-

tion.








Three of the perceptual tasks were designed to assess

subjects' ability to discriminate between pairs of mandibular

positions in the three planes of space. These tasks include

discrimination of pairs of positions in the vertical dimension

(interdental thickness discrimination), in the lateral dimen-

sion (discrimination of lateral mandibular positions), and in

the anterior-posterior dimension (discrimination of anterior-

posterior mandibular positions).

The fifth and final perceptual task required subjects

to make judgements between pairs of weighted capsules placed

between the maxillary and mandibular incisors. This task was

included in an attempt to either implicate or rule out the

sensory mechanism of the TMJ as having a role in interdental

weight discrimination. Tasks were presented in a random order.


Duplication of an interdental space

This task required each subject to reproduce an arbi-

trarily determined, comfortable open mouth position somewhere

between the closed or physiologic rest position and a maximum

open mouth position (Thilander, 1961). The amount of mouth

opening was determined by measuring the distance between the

upper and lower central incisors with a plastic ruler.

Measurements were taken to the nearest millimeter. The ruler

was shaped so that one end would fit over the incisal edge of

the lower incisors to insure standard measurement conditions.

Each subject was instructed to remember the initial mouth

or jaw open position and then to attempt to replicate this

same position ten times in close








succession. The distance between the upper and lower central

incisors was measured and recorded by the examiner for each

of the ten subsequent trials. The subject was not informed

as to the accuracy of his responses.


Interdental thickness discrimination

This task required each subject to make judgements

concerning the thickness of blocks placed in pairs, one at

a time, between the maxillary and mandibular central incisors.

The instrumentation used in this task, which was developed

by Williams and LaPointe (1972), is illustrated in Figure

8 and consists of 21 acrylic blocks, each 4.5 cm long by

1.5 cm wide. The thickness of the blocks varies in 1 mm

increments and ranges from 10 to 25 mm. In performing this

task, each subject was asked to judge whether the second

block of each pair was "the same," "thicker," or "thinner"

than the first block of the pair. The first block in

each pair presentation was considered the "standard" and was

always 10 mm thick. The second block presented in each pair

was a different thickness. A modified "method of limits"

procedure, with two ascending runs, was used to arrive at

each subject's difference limen. A "run" was defined as

the presentation to the subject of as many different pairs

of blocks as necessary until two consecutive correct judge-

ments were made.


Discrimination of lateral mandibular positioning

Each subject's ability to discriminate differences in







































Figure 8
Acrylic Blocks for Assessing
Interdental Thickness Discrimination







































Figure 9
Devices for Assessing Anterior-Posterior and
Lateral Mandibular Placement Discrimination








mandibular position lateral to a midline position was

assessed using an instrument designed and developed by

Williams and LaPointe (1973). This instrument is illustrated

in Figure 9. The device consists of two interlocked, sliding

plates that are adjustable in one-half millimeter increments

by means of a thumb screw which allows for controlling the

position of one plate in relation to the other. The v-shaped

wedge on the upper plate was positioned in the space between

the two maxillary incisors. The subject then moved his jaw

about until the lower plate seated between the space of the

two mandibular incisors. This task required the subject to

make judgements concerning the lateral position of his lower

jaw as determined by the positions of the lower wedge, which

were presented to him, in pairs, one at a time. Each subject

was asked to judge whether the second position was "the same,"

"to the left," or "to the right" of the first position. The

first position, considered the "standard," was always that

position where upper and lower wedges were in a vertical line.

The second position in each pair was a different position

either to the left or to the right of midline. Again, a

modified "method of limits" procedure, with two ascending runs,

was used to arrive at each subject's difference limen in a left

or right direction. As in the interdental thickness task, a
"run" was defined as the presentation of as many different

pairs of wedge settings as necessary until two consecutive

judgements were made.








Discrimination of anterior-posterior mandibular positions

Each subject's ability to discriminate between mandibular

positions anterior to a position in which the maxillary and the

mandibular incisors are in a vertical line was assessed

utilizing the same instrument which was used in assessing

lateral discrimination ability. For the anterior-posterior

task, however, the inverted v-shaped wedge on the upper plate

(shown at left of instrument in Figure 9) was placed over

the maxillary incisors seated in the wedge on the lower plate.

This task required the subject to make judgements concerning

the anterior position of his jaw as determined by the positions

of the lower wedge which were presented to him in pairs, one at

a time. Each subject was asked to judge whether the second

position of each pair was "the same," "forward," or "backward"

compared to the first position. The first position, again

considered the "standard," was always that position where the

upper and lower wedges were in a vertical line. The second

position of each pair was a different position anterior to the

first. The same modified "method of limits" procedure, with

ascending runs, was used to determine each suject's threshold

of detecting differences in jaw positions in the anterior

direction. A "run" was defined as it had been for the pre-

ceding tasks.


Interdental weight discrimination

This task was used to assess each subject's ability to

discriminate between pairs of weighted capsules. The task

utilized the instrumentation shown in Figure 10. The







































Figure 10
Weighted Acrylic Capsules for Assessing
Interdental Weight Discrimination








instrumentation was developed by Williams and LaPointe (1972)

and uses 21 capsules ranging in weight from 5 to 25 grams.

This task required each subject to make judgements between

pairs of weighted capsules which were presented, one at a time,

between the maxillary and the mandibular central incisors.

Each subject was asked to judge whether the second of each

pair of capsules was "the same," "heavier," or "lighter" than

the first capsule. The first capsule was always the "standard"

weight of 5 grams. The second capsule of each pair was always

heavier than the first. A modified "method of limits," with

two ascending runs, was used to arrive at each subject's

difference limen. A "run" was defined as for the previous

perceptual tasks.


Nonspeech Oral Movements

Tasks of nonspeech oral movement were included in the

study since evidence suggests that the neurological process

governing speech and nonspeech oral movements are dissimilar.

Hixon and Hardy (1964) suggested that speech movements may be

the result of automatic, programmed motor patterns, while less

practiced nonspeech oral movements, such as repetitive raising

the tongue to and dropping it from the alveolar ridge, would

require voluntary, concentrated motor movements.

Two nonspeech oral movements were used on this study to

examine the role of the sensory mechanism of the TMJ for

regulating mandibular movement and positioning for nonspeech

activities. These tasks required each subject to: 1) elevate

the tongue tip up against the alveolar ridge and to drop it








from this contact and 2) elevate the dorsum of the tongue up

against the roof of the mouth and drop it from this contact.

Each of these two tasks were performed three times by each

subject.


Speech Sample

A primary purpose of the study was assessment of the

effects of the experimental conditions on mandibular posi-

tion during speech production. A speech sample was devel-

oped which provided varied amounts of lingual-palatal con-

tact, required a wide range of mandibular positioning, and

contained a wide range of speech sounds. The speech sample

required each subject to produce a series of diphthongs, a

series of vowel-consonant-vowel (VCV) combinations, as well

as a sample of connected speech.


Vowel-consonant-vowels: /isi/, o/s-./, /iki/, and /lkka/

The VCV combinations were formed using consonants and
vowels that have been reported to require a wide range of

mandibular placements. Kent and Moll (1972) and Owens (1973)

have shown that front consonants, such as the /s/, and high

vowels, such as /i/, are produced with a more elevated man-

dibular placement than are the back consonants, such as /k/

and the low vowels, such as /a/. Therefore, the following

VCV combinations were developed: /isi/, /asoa, /iki/, and

/akLk/. Each of the VCV combinations were spoken three times

by each subject for three of the conditions. Subjects were

instructed to put the same stress on the second vowel as

they did on the first one.








Diphthongs: /al/, /eI/, /aU/, /oI/

A diphthong has been defined by Wise (1957) as two

vowels pronounced in a quick, unbroken succession within a

syllable, and connected by a gliding series of unrelated

sounds. Four diphthongs were included in the speech sample

because of their unique arrangement consisting of a low or

mid vowel and a high vowel. Production of these diphthongs

requires considerable mandibular and lingual movement with

minimal lingual-palatal contact. The diphthongs used in this

study were: /al/, as in the word "high," /el/, as in the word

"hay," /3I/, as in the word "hoist," and /aU/, as in the word

"how." As for production of the VCV combinations, each of the

diphthongs were spoken three times by each subject for each of

the three conditions.


Connected speech

The sentence "In the evening Connie watches TV with me."

was selected as a representative sample of ongoing speech. It

contains a distribution of front and back consonants, such as

/t/ and /k/, as well as vowels which represent the extremes of

the vowel triangle, such as /i/ and /-/. Each subject was

instructed to repeat the sentence in their usual speaking

manner relative to such factors as intensity, duration, and

inflectional patterns.


Experimental Procedures
Two experimental conditions were developed for this

study. The experimental conditions were: 1) unilateral anes-
thetization of the right auriculotemporal nerve (innervating

the right TMJ)








and 2) anesthetization of the right auriculotemporal nerve

with a painless pressure administered to the contralateral

TMJ capsule. All of the experimental tasks outlined were

performed by each subject under each of the experimental

conditions and under a normal condition where the subject

received neither anesthesia nor pressure stimulus.


Anesthetization

Anesthetization of the auriculotemporal nerve was

performed and observed by Parker E. Mahan, D.D.S., College

of Dentistry, University of Florida. A 2% xylocaine solution,

with a vaso-constrictor, was injected into the nerve as it

ascends near the posterior border of the mandible. Approx-

imately 0.8 cc of xylocaine was used for each anesthetization.

The anesthetized state was maintained for approximately

three to four hours as evidenced by subject report. All

subjects received the anesthesia on their right side.


Pressure

The second experimental condition involved applying

pressure to the left TMJ capsule while the right TMJ was

anesthetized. The pressure device, illustrated in Figure 11,

incorporates a calibrated, spring-loaded disc 2.5 cm in

diameter. The design allows for monitoring the amount of

force that the disc exerts against the TMJ capsule. The

amount of pressure, acknowledged as less than painful

by each subject, varied from 1.0 to 2.0 pounds. The mean








































Figure 11
Cephalostat and Pressure Device








amount of pressure used was 1.8 pounds.

The pressure device was attached to a cephalostat,

which is also illustrated in Figure 11. The cephalostat

was designed to fit around the subject's head, in a halo

fashion, with four points of contact for stabilization, two

anteriorly and two posteriorly. This design prevented any

interference with the movement of the muscles of mastica-

tion. Both the cephalostat and the pressure device were

designed by the author and were constructed in the Bioinstru-

ment Shop at Shands Teaching Hospital, University of Florida.



Filming Procedures

The nonspeech oral movements and speech tasks were re-

corded cinefluoroscopically. A 16 mm Auricon Cine II Voice

camera mounted on a Picker fluoroscope, with a five inch

image intensifier, was used to obtain the cinefluorographic

films of the speech structures during the production of the

nonspeech oral movements and during production of the speech

sample. Eastman Kodak Double X film (type 7222) with a mag-

netic sound strip was used. The filming speed was 24 frames

per second. The film was processed in a Smith-Picker auto-

matic processor. The radiographic and the film processing

equipment are located in Shands Teaching Hospital, University

of Florida.

Each subject was filmed in a upright sitting position

with his head positioned and stabilized in the cephalostat.

A radiopaque, stainless steel ruler, with holes drilled into








it at centimeter intervals, was inserted in the subject's

mouth at the initiation of filming. It was, therefore, pos-

sible to project the filmed image at some known magnification

relative to life size.


Procedures For Film Data Collection


Measuring Apparatus

A Lafayette Analyzer 16 mm Projector was used to analyze

the cinefluorographic films. The Lafayette Projector is cap-

able of frame by frame oroiection or continuous projection at

variable speeds. The image of the subject and the ruler was

projected one and one half times larger than life size by ad-

justing the position of the perpendicularly mounted tracing

board relative to the projector. It was necessary to project

the image to this size because of the limitation of the pro-

jector to focus the image any smaller. All of the measure-

ments were corrected to life size following compilation of

the data.


Construction of Template

Prior to measurement, a template was constructed from

the projected image of the initial frame depicting the mid-

line structures. The midline structures included the hard

palate from the anterior nasal spine to the posterior nasal

spine, the upper central incisors, and the alveolar ridge.

These structures were used for constucting lines of reference

as well as for adjusting the template to the frame to be mea-

sured in order to insure accuracy of measurement.








Planes of Reference

Three lines of reference were constructed on the template

for measurement of the vertical and horizontal positions of

the mandible. Figure 12 illustrates these lines of reference.

Line PP. This line defines the palatal plane which is a

standard reference line in cephalometric studies. This line

is defined as a line which passes through the midpoint of the

anterior nasal spine and the midpoint of the posterior nasal

spine. This line was chosen because it approximates the

horizontal plane and provides a reference line for measuring

the vertical position of the mandible.

Line AB. This line represents a plane which is parallel

to the palatal plane and is tangent to the most inferior point

of the central maxillary incisor. This line also approximates

a horizontal plane and allows for easier measuring of vertical

jaw positions than would making measurements from the central

mandibular incisor to the palatal plane. The vertical posi-

tion of the mandible was recorded relative to this line.

Line CD. This line represents a plane which is perpen-

dicular to the palatal plane. This line passes through the

most inferior midpoint of the upper central incisor. This line

approximates a vertical plane and serves as the reference for

measuring the horizontal positioning of the mandible.


Definition of Measurements

The vertical and horizontal positions of the mandible

were measured relative to the planes of reference defined











































Measurement of vertical mandibular displacement noted
in a downward or positive (+) direction.

Measurement of vertical mandibular displacement noted
in an upward or negative (-) direction.

Measurement of horizontal mandibular displacement noted
in a backward or positive (+) direction.

Measurement of horizontal mandibular displacement noted
in a forward or negative (-) direction.

Figure 12
Defined Measurements of Mandibular Displacement
and Associated Positive and Negative Values








above and illustrated in Figure 12. The following discussion

defines the vertical and horizontal measurements of mandibular

displacement.

Measurement of vertical mandibular position. Measurement

of the vertical position of the mandible was defined as the

perpendicular distance between the superior tip of the mandi-

bular central incisor and line AB. A positive value was

assigned when the tip of the lower central incisor was below

AB and a negative value was recorded when the tip of the

incisor was above line AB.

Measurement of horizontal mandibular position. The

horizontal position of the mandible was defined as the perpen-

dicular distance between the tip of the mandibular incisor

and line CD. Positive values were assigned when the position

of the tip of incisor was posterior to the line CD. Negative

values were assigned when the tip of the incisor was observed

to be in front of line CD.


Identification of Frames Measured for the Speech and Nonspeech
Tasks

The initial and the final frames of each of the nonspeech

and the speech tasks were located and marked. The segment of

film portraying the production of each of the tasks was then

numbered consecutively, frame by frame, for ease of identifi-

cation.


Nonspeech tasks

Tongue tip to alveolar ridge. The frame identified as the

initiation of this nonspeech task of elevating the tongue tip








to the alveolar ridge was defined as that frame showing the

tongue first making contact with the alveolar ridge. The

final frame for that task sequence was identified as that frame

showing the tongue in its lowest position just prior to its

elevation for the beginning of the next trial. In addition,

a third frame was identified in which the tongue was observed

to be releasing contact from the alveolar ridge. It was,

therefore, possible to define the position of the mandible at

the beginning and at the end of the three trials for this

task, as well as the range of mandibular movement throughout

each trial. The length of time (in number of frames) for the

completion of each trial and the length of time of lingual

palatal contact was defined also.

Tongue dorsum to palate. The frame identified as the ini-

tiation of this nonspeech act was defined as that frame showing

the tongue contacting the palate approximately at the posterior

nasal spine. The frame showing the tongue in its lowest posi-

tion just prior to elevation for the beginning of the following

trial was defined as the final frame in each trial. A third

frame showing the tongue releasing contact from the palate

was also identified. Again, it was possible to define the

position of the mandible at the initiation and completion of

each trial for this task and the range of mandibular movement

through each trial. The length of time for the completion of

each trial and the amount of time during which the tongue

was in contact with the palate was recorded also.








Vowel-consonant-vowels: /isi/, /asa/, /iki/, and /aka/

Those frames identified as the beginning and the end of

each VCV sequence were defined in terms of optimal lingual

placement for the production of the two vowels /i/ and /a/.

The frame showing the vowel /i/ as it occurred in the

initial position of the VCV sequence was defined as that frame

picturing the tongue in its highest position prior to its

movement for the production of the following consonant. The

frame showing the vowel /a/ as it occurred in the initial

position was defined as that frame showing the lowest tongue

position prior to its movement for the production of the

following consonant.

The frame showing the vowel /i/ as it occurred in the

final position of the VCV sequence, was defined as that frame

showing the tongue in its highest position prior to its move-

ment to a rest position. The frame showing the vowel /a/, as

it occurred in the final position of the VCV sequence, was

defined as that frame showing the tongue in its lowest position

prior to its movement to a rest position.

In addition to the initial and the final frames of each

trial, those frames depicting the lingual palatal contact

required for consonant production were identified. Thus, it

was possible to define the vertical and the horizontal position

of the mandible at start and finish of each trial as well as

during consonant production. These measurements also provided

the range of mandibular motion throughout each trial. The

length of time for the completion of each trial and the amount

of time required for the production of the consonants and the

vowels were recorded also.








Diphthongs: /al/, /el/, /aU/, and /,I/

The initial and the final frames representing the pro-

duction of each of the diphthongs were identified as those

frames showing optimal tongue or lip placement for the produc-

tion of the respective vowels.

The frames identified as the production of the vowels

/a/, /e/, and /3/ as they occur in the initial positions of
the diphthongs /al/, /el/, and /)I/ respectively were defined

as those frames showing the tongue in its lowest position

prior to elevation for the production of the second vowel in

the diphthong. The frame identified as the production of the

vowel /a/ in the initial position of the diphthong /aU/ was

defined as that frame showing the lip in its lowest position

prior to its elevation for rounding in the production of the

second vowel in the diphthong.

The frames identified as the production of the vowel

/I/ as it occurs in the final position of the diphthongs /aI/,

/el/, and /.I/ were defined as those frames showing the
tongue in its highest position prior to its lowering for the

initiation of the next trial. The frame identified as show-

ing the production of the vowel /U/ as it occurs in the final

position of the diphthong /aU/ was defined as the frame show-

ing the lower lip in its highest position prior to its lowering

for the beginning of the next trial.

It was possible, therefore, to define the vertical and
horizontal position of the mandible at the beginning and at

the end of the production of each trial as well as the range








of mandibular motion through each trial. The length of time

required to complete each trial was recorded also.

Sentence

Seventeen frames depicting the production of seventeen

speech phonemes were selected from the sentence, "In the

evening Connie watches TV with me." The selected phonemes are

represented by the underlined graphemes in the sentence below.

IN TH E E V E N I N G C 0 N NIE W A T C H E S TEE
1 2 3 4 5 6 7 8 10 11 T2

V E E W I T H M E.
T3 14 15 1 6 17

The definitions for identifying these phonemes within the

sentence from cinefluorographic recordings have been described

in detail by Owens (1973) and have been duplicated here for

convenience.

1. The /5/ of "the" was defined as the lingual-dental contact

immediately following the lingual-alveolar contact required

for the production of the phoneme /n/ of "in".

2. The /i/ of "evening" was defined as the highest point of

lingual elevation preceding the labial-dental contact re-

quired for the production of the phoneme /v/ of "evening".
3. The /v/ of "evening" was defined as the labial-dental

contact necessary for its production.

4. The /1/ of "evening" was defined as the part of lingual-

velar contact between the back of the tongue and the velum

while the velum was down.

5. The /k/ of "Connie" was defined by the lingual-velar contact

required for its production while the velum was








closing off the velopharyngeal port.

6. The /,/ of "Connie" was defined as the lowest and most

posterior point of lingual movement preceding the lingual-

alveolar contact required for the production of the phoneme

/n/ of "Connie".

7. The /n/ of "Connie" was defined as the lingual-alveolar

contact required for its production.

8. The /w/ of "watches" was defined by the maximum forward

movement of the lips required for its production,

9. The /a/ of "watches" was defined as the lowest and most

posterior point of lingual movement preceding the lingual

alveolar contact required for the production of the /V /

of the word "watches".

10. The /y/ of "watches" was defined as the lingual-alveolar

(sometimes lingual-palatal) contact required for its pro-

duction while the teeth were closed and the lips pro-

truded slightly.

11. The /t/ of "TV" was defined as the lingual-alveolar con-

tact required for its production.

12. The first /i/ of "Tee Vee" was defined as the highest point

of ligual movement preceding the labial-dental contact re-

quired for the production of the phoneme /v/ of "TV".
13. The /v/ of "TV" was defined as the labial-dental contact

required for its production.

14. The second /i/ of "Tee Vee" was defined as the highest

point of lingual elevation preceding the forward move-

ment of the lips required for the production of the

phoneme /w/ of "with".








15. The /8/ of "with" was defined as the lingual-dental

contact required for its production.

16. The /m/ of "me" was defined as the bilabial contact re-

quired for its production.

17. The /i/ of "me" was defined as the highest point of

lingual elevation following the bilabial contact required

for the production of the phoneme /m/ of "me".

Reliability

Since the author made all measurements, only inter-

measurer reliability was assessed. The vertical and horizontal

measurements were remeasured for forty-five frames. The cor-

relation between the initial and the second measurements was

calculated. A correlation coefficient of .99 was obtained for

the forty-five vertical measurements and a coefficient of .97

was obtained for the forty-five horizontal measurements. These

correlation coefficients are considered to be within acceptable

limits.













CHAPTER FOUR
RESULTS


The results of this study will be presented relative to

1) descriptive analysis of the data and 2) statistical analysis

of differences between the experimental and control conditions.

Descriptive analysis was completed for the five perceptual mea-

sures and the connected speech passage. Measurements of cen-

tral tendency and the dispersion of performance on each of the

test measures accompanies a narrative description of the re-

sults. Statistical analysis was completed for ten test mea-

sures including the two nonspeech tasks, the four tasks of

diphthong production, and the four tasks of vowel-consonant-

vowel production. The statistical analysis included an ana-

lysis of repeated measures and the Newman-Keuls analysis. A

more detailed description of the statistical procedures fol-

lows the presentation of the results for the perceptual mea-

sures and sentence production.


Analysis of Perceptual Tasks and Connected Speech

Perceptual Measures

Duplication of interdental space

This task was included in an attempt to replicate a

portion of Thilander's (1961) study. Table 1 displays subject














Table 1
Individual Performance Scores and Group Means,
Ranges, and S.D.'s for Duplication of Interdental
Space Task: Range of Jaw Position for Ten Trials



Condition

Subject Normal Anesthetized Anesthetized and Pressure


3.0 mm

8.0

2.0

11.0


5.0 mm

4.0

6.0

7.0


Means 6.00 mm 5.50 mm

Standard
Deviation 4.24 1.29


3.0 mm

2.0

7.0

4.0


4.00 mm


2.16








performance during attempts to duplicate the standard position

ten times under the three conditions. Included in Table 1 are

means and standard deviations for the group of four subjects.

Anesthesia appeared not to make it more difficult for the

subjects to find the standard jaw opening; the mean for the

normal condition is 6.00 mm, while the mean for the anesthesia

condition is 5.50 mm. However, three subjects (A, B, and D)

of the four found it easier to duplicate the standard position

when a light pressure was applied to the left TMJ. This is

also reflected in a reduced mean performance score for the

pressure condition; X = 4.0 mm.

The mean difference in jaw position from the standard

position, as well as standard deviation, is presented in Table

2. The means obtained for each of the three conditions sug-

gest that neither the anesthesia nor the anesthesia and pres-

sure had an affect on the ability of the subjects to dupli-

cate the standard. The means vary from a 3.25 mm for the

anesthesia and pressure condition to a 3.65 mm for the normal

condition.

Analysis of individual subject means presents somewhat

conflicting results. The ability of subjects A and C to du-

plicate the standard was impaired somewhat by the anesthesia

condition. However, performance was improved by pressure to

the opposite TMJ only for subject A. Subject D's performance

also was improved by pressure, however, his performance under

anesthesia was better than under the control condition. More-

over, the performance of subjects A and C was impaired by














Table 2
Individual Performance Scores and Group Means,
Ranges, and S.D.'s for Duplication of Interdental
Space Task: Mean Difference of Jaw Position from
the Standard



Condition


Normal Anesthetized ed and Pressure


2.4 mm


Means

Standard
Deviation


4.4 mm


3.65 mm 3.52 mm


0.8 mm


3.25 mm


2.83


Subject


Subject_ __ __ _


~


0.96








anesthesia compared to normal and the performance of A and D

was improved by pressure compared to anesthesia. Only subject

A fit the profile of performance presented by Thilander of

impaired performance under anesthesia condition and improved

under the pressure condition.

Interdental thickness discrimination

Individual subject performance scores for each of the

two runs are presented for the task of interdental thickness

discrimination in Table 3. The mean amount of thickness re-

quired for two consecutive correct descriminations is greater

for anesthesia condition (1.75 mm) than for the normal con-

dition (1.38 mm). Subjects required an average of 1.50 mm

difference under the pressure condition. This suggests that

some mild disruption occurred due to the anesthesia and some

recovery of discriminative abilities occurred with the ap-

plication of pressure. Further analysis (Table 4) revealed

that 100% correct discrimination occurred under the normal

condition and pressure condition when the difference in

block size was 2 mm. However, 4 mm were required under the

anesthesia condition in order to obtain 100 % discrimination.


Discrimination of lateral mandibular position

Each subject's ability to discriminate between pairs of

lateral positions of the mandible was assessed to the left of

and to the right of midline, No difference in subjects' per-

formance was observed between the control and anesthesia con-

dition when ability on this task was tested to the left of














Table 3
Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Interdental
Thickness Discrimination



Condition
Subject Trial Normal Anesthetized Anesthetized and Pressure


A 1)

2)

B 1)

2)

C 1)

2)

D 1)

2)






Means

Standard
Deviation


1.0 mm

1.0

1.0

2.0

2.0

1.0

1.0

2.0


2.0 mm

1.0

1.0

1.0

1.0

2.0

2.0

4.0


1.38 mm 1.75 mm


1.0 mm

1.0

1.0

1.0

2.0

2.0

2.0

2.0


1.50 mm


0.52 1 .04 0.53


0.52


1.04


0.53





71






Table 4
Mean Percent of Correct Subject Responses per
Stimulus Pair on a Measure of Interdental
Thickness Discrimination


Condition
Stimulus Pairs Normal Anesthetized Anesthetized and Pressure

10 mm 11 mm 62.5% 57% 50%

10 mm 12 mm 100 87.5 100

10 mm 13 mm 100 87.5 100

10 mm 14 mm 100 100 100








midline. (Table 5: X = 1.69 mm and X = 1.62 mm, respectively)

Subjects, as a group, found it easier to discriminate between

positions to the left of midline under the pressure condition

(X = 1.25 mm).

The mean percent of correct subject responses per

stimulus pairs for jaw positions to the left of midline are

presented in Table 6. These data illustrate that subject

performance reached 100% for the normal and anesthesia con-

ditions when the difference between the pair of positions

reached 2.5 mm. Only 2.0 mm difference was necessary for

100% performance under the pressure condition. Moreover, the

group means presented in Table 5 and the mean percent of cor-

rect subject responses presented in Table 6 for discrimina-

tion of jaw positions to the left of midline suggest that

anesthesia had no effect on the subject's discriminative

abilities while pressure to the TMJ, contralateral to the

anesthesia, enhanced performance somewhat. It should be

noted that pressure was always applied to left TMJ capsule,

or, for this task, to the side of jaw movement.

Subject performance scores, group means, and S.D.'s

are presented in Table 7 for the task of discrimination be-

tween pairs of lateral jaw positions to the right of midline.

The group means presented in Table 7 suggest that this group

of subjects performed most accurately under the normal

condition (X = 1.12 mm) and performed least accurately under

the pressure condition (X = 2.06 mm). The group mean for the

anesthesia condition (X = 1.45 mm) fell between the two other














Table 5
Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Lateral Jaw
Position Discrimination for the Left


Condition

Subject Trial Normal Anesthetized Anesthetized and Pressure

A 1) 3.0 mm 1.0 mm 1.0 mm

2) 2.0 1.5 1.5

B 1) 0.5 1.0 0.5

2) 1.5 1.0 2.0

C 1) 1.0 1.5 0.5

2) 1.0 1.0 0.5

D 1) 2.0 2.5 1.5

2) 2.5 3.5 2.5






Means 1.69 mm 1.62 mm 1.25 mm

Standard
Deviation 0.84 0.92 0.76













Table 6
Mean Percent of Correct Subject Responses per
Stimulus Pair on a Measure of Discrimination of
Lateral Jaw Position Discrimination to the Left


Condition

stimulus Pairs Normal Anesthetized Anesthetized and Pressure

mm 0.5 mm 37.5% 87.5% 37.5%

mm 1.0 mm 50 62.5 75

mm 1.5 mm 50 75 75


0 mm 2.0 mm

0 mm 2.5 mm

0 mm 3.0 mm

0 mm 3.5 mm

0 mm 4.0 mm

0 mm 4.5 mm

0 mm 5.0 mm


75

87.5

100

100

100

100

100


100

87.5

100

100

100

100

100


87.5

100

100

100

100

100

100


St

0

0

0














Table 7
Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Lateral Jaw
Position Discrimination to the Right


Condition

Subject Trial Normal Anesthetized Anesthetized and Pressure


A 1)

2)

B 1)

2)

C 1)

2)

D 1)

2)


Means


1.5 mm

1.0

2.0

1.0

1.0

0.5

0.5

1.5


2.5 mm

1.0

1.0

1.5

0.5

0.5

1.5

3.0


1.12 mm 1.45 mm


2.5 mm

1.0

2.0

2.0

1.0

0.5

4.5

3.0


2.06 mm


Standard
Deviation 0.52


0.23


0.74













Table 8
Mean Percent of Correct Subject Responses per
Stimulus Pair on a Measure of Discrimination of
Lateral Mandibular Position Discrimination to
the Right


Stimulus Pairs


mm 0.5 mm

mm 1.0 mm

mm 1.5 mm

mm 2.0 mm

mm 2.5 mm

mm 3.0 mm

mm 3.5 mm

mm 4.0 mm

mm 4.5 mm

mm 5.0 mm


Condition

Normal Anesthetized Anesthetized and Pressure


37.5%

75

87.5

100

100

100

100

100

100

100


25%

50

87.5

87.5

87.5

100

100

100

100

100


25%

50

50

75

75

87.5

100

87.5

100

100








condition means.

Table 8 presents the mean percent of correct subject

responses per stimulus pair for the task of lateral jaw posi-

tion discrimination to the right of midline. These data

demonstrate also that subjects' ability to perceive differ-

ences in positions to the right of midline was hampered by

the application of pressure to the left TMJ capsule.


Anterior-posterior jaw position discrimination

Table 9 presents the individual and group performance

scores for anterior-posterior jaw position discrimination.

The group means illustrate that the subjects'; performance

was equal for the anesthesia and the pressure conditions.

Table 10 presents the mean percent of correct subject re-

sponses per stimulus pair for this task. Subjects per-

formed less accurately in discrimination between pairs of

anterior-posterior jaw positions under the normal control

condition than under the experimental conditions. 100%

performance was attained when the difference between pairs

was 1.0 mm for the anesthesia and the pressure conditions.

For the normal condition, 100% performance was not reached

until the difference between pairs of jaw positions was

2.5 mm.


Discrimination of interdental weights

Individual and group performance scores for the task

of interdental weight discrimination can be found in Table

11. The anesthesia condition had little effect on subjects'













Table 9
Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Anterior-Posterior
Jaw Position Discrimination


Condition

Subject Trial Normal Anesthetized Anesthetized and Pressure

A 1) 1.5 mm 0.5 mm 0.5 mm

2) 2.5 0.5 0.5

B 1) 0.5 0.5 0.5

2) 0.5 0.5 1.0

C 1) 0.5 0.5 0.5

2) 0.5 1.0 1.0

D 1) 0.5 1.0 1.0

2) 2.0 0.5 0.5






Means 1.06 mm 0.62 mm 0.68 mm

Standard
Deviation 0.82 0.94 0.23













Table 10
Mean Percent of Correct Subject Responses per
Stimulus Pair on a Measure of Discrimination
of Anterior-Posterior Jaw Positions


Condition
Stimulus Pairs Normal Anesthetized Anesthetized and Pressure

0 mm 0.5 mm 87.5% 75% 75%

0 mm 1.0 mm 100 100 100

0 mm 1.5 mm 75 100 100

0 mm 2.0 mm 87.5 100 100

0 mm 2.5 mm 100 100 100

0 mm 3.0 mm 100 100 100














Table 11
Individual Performance Scores and Group Means,
Ranges, and S.D.'s for a Task of Interdental
Weight Discrimination


Condition

Subject Trial Normal Anesthetized Anesthetized and Pressure

A 1) 5.0 gms 14.0 gms 5.0 gms

2) 6.0 6.0 5.0

B 1) 13.0 4.0 11.0

2) 11.0 4.0 12.0

C 1) 7.0 5.0 2.0

2) 8.0 6.0 6.0

D 1) 4.0 6.0 12.0

2) 7.0 12.0 16.0






Means 7.62 gms 7.12 gms 8.62 gms

Standard
Deviation 3.01 3.75 4.47








ability to discriminate between paired weights. Group means

are 7.62 gms for the normal condition and 7.12 gms for the

anesthesia condition. Pressure appeared to make discrimina-

tion between interdental weights more difficult. The mean

difference required was 8.62 gms for this condition.


Summary: perceptual measures

Anesthesia to the right auriculotemporal nerve appeared

to have a mild disruptive influence on this group of subjects'

abilities to discriminate between the thickness of pairs of

blocks placed interdentally. Pressure to the contralateral

(left) TMJ capsule restored discriminative ability somewhat

(Tables 3 and 4).

Pressure to the left TMJ appeared to enhance subject

performance of tasks where anesthesia had no disruptive

effects. These tasks include Thilander's task of replicating

a standard interdental space ten times (Table 1), discrimi-

nation between pairs of lateral jaw positions to the left of

midline (Table 5), and discrimination between pairs of

anterior-posterior jaw positions (Table 9). On the other

hand, pressure to the left TMJ capsule appeared to be dis-

ruptive of subjects' ability to discriminate between pairs

of lateral jaw positions to the right of midline (Tables 7

and 8). Pressure appeared to have a disruptive effect on

subjects' ability to discriminate between the weights of

capsule pairs placed between the incisors (Table 11). Neither

of the experimental conditions appeared to influence the

subjects' performance on Thilander's task of duplicating a

standard jaw position when that task ia analyzed by the mean








difference of jaw positions from the standard position.


Sentence

Figure 13 combines a tabular and graphic representation

of the vertical jaw displacement (N = 4) for the seventeen

phonemes under each of the three conditions. The mean, range,

and standard deviation are entered below each phoneme. Figure

14 presents the complimentary data for horizontal mandibular

displacement. Since measures from the film were made at one

and one-half life size (Chapter Two), all measurement values

were reduced by one-third to achieve absolute values. Statis-

tical significance could not be assessed due to the small

number of observations.

Figure 13 demonstrates that similar vertical patterns of

jaw movement are maintained under each of the test conditions.

The most closed jaw postures are observed for the /tJ / in

"watches" and the /t/ in "TV." The greatest amount of mandi-

bular displacement is observed for the /a/ in "Connie" and the

/a/ in "watches." These observations are compatible with

previous research findings (Kent and Moll, 1972 and Owens,

1973).

In general, vertical jaw displacement was greatest for

the anesthesia condition and least for the pressure condition.

Under anesthesia, jaw displacement was equal to normal for the

initial speech sounds in the sentence. As the amount of re-

quired displacement increased for the open sounds in "Connie"

and "watches," the jaw opened more for the anesthesia condi-

tion than for the normal condition. As the



























Phoneme A 1 v
IN T HE E V
Normal -
Mean 3.35 5.19 3.35
Range 4.69 5.36 5.36
Std.Dev. 2.12 2.34 2.44

Anesthetized
Mean 3.52 5.02 3.52
Range 6.03 4.69 3.35
Std.Dev. 2.59 2.08 1.76
Anesthetized and Pressure
Mean 2.85 4.36 2.85
Range 5.36 5.36 4.69
Std.Dev. 2.34 2.47 2.28


3.52
6.03
2.75


Co n w f t I v 1 8 m i
C 0 N N I E W ATC E S TEE V E EW I T H M E
7.37 5.53 5.70 7.70 0.84 -.34 2.18 1.67 3.02 3.52 3.35 3.5
9.38 8.04 8.71 8.04 2.68 3.35 4.02 3.35 4.69 5.36 4.69 6.7
4.17 3.92 4.11 3.52 1.38 1.39 1.84 1.59 1.93 2.64 2.12 2.S


4.52 4.36 8.21 6.70 5.19 6.36 0.34 -.34 3.68 2.85 3.68 4.52
6.70 5.36 8.04 4.02 7.37 8.71 3.35 4.02 3.35 3.35 4.69 4.02
2.81 2.28 3.64 2.12 3.34 3.89 1.59 1.77 1.59 1.58 1.93 2.14


2.8513.68
4.02 4.69
1.84 1.93


6.03 4.52 3.68 4.69 -.84 -.00 1.68 1.34 1.84
4.02 2.60 4.02 5.36 3.35 4.69 4.02 2.68 4.69
1.97 1.38 1.77 2.25 1.58 2.08 2.01 1.54 2.27


4.19
3.35
1.76


2.85 2.34
3.35 4.02
1.70 2.01


Figure 13
Means, Ranges and S.D.'s of Vertical Jaw Positions Under Three
Conditions for 17 Sounds Selectea From a Connected Apeech Sample (N-4)








amount of required jaw displacement decreased for the conso-

nants at the end of "watches" and in "Tee Vee", the jaw began

to close sooner for anesthesia. Jaw displacement for the

/tf/ in "watches" and /t/ in "Tee Vee" appeared equivalent

for the two conditions. As the amount of required jaw dis-

placement increased for the open sounds at the end of the

passage, the jaw opened more for the normal condition. This

is interpreted as over-shooting of the target position for

the production of open speech sounds.

On the other hand, pressure appeared to reduce vertical

displacement. It appeared to do so consistently over all the

speech elements in the speech sample, both open and closed,

The pattern of jaw posturing in the horizontal dimen-

sion is similar also for the three conditions, Figure 14.

The most anterior jaw postures are observed for the /tf/ in

"watches" and the /t/ in "Tee Vee". The most retruded pos-

tures are observed for the /a/ and /n/ in "Connie" and the

/a/ in "watches". These observations, again, are compatible

with previous research findings (Kent and Moll, 1972 and

Owens, 1973). The findings also support observations of the

hinge action of the mandible. That is, the greater the

vertical displacement of the mandible, the more retruded the

structure will be.

The effects of anesthesia and pressure observed in the

vertical dimensions are not readily apparent in the horizontal

plane. The path of jaw movement for any one condition inter-

sects the others.













6
E E
WE
E 5-
CC
C-- 4



S2-
o:
4.-
0
0 0

Phoneme
I
Normal -
Mean
Range
Std.Dev.


Pressure
.69 4.0
3.35 2.68
1.85 1.22


5.02 4.69 3.52 4.19 2.18 2.01
3.35 4.02 4.02 4.02 4.02 4.02
1.59 1.81 1.76 1.76 1.77 1.73


SE E V E I H M E
S TE E V EE EW I T H M E


1.84 2.68 3.02
2.01 2.68 2.68
1.00 1.22 1.59


2.34 2.84 3.02
2.68 3.35 4.02
1.16 1.48 1.77


3.68 4.36
2.68 2.01
1.28 1.16


4.36 4.36 4.86
2.01 2.68 2.35
1.16 1.28 1.48


4.02 4.02 3.86 4.86
4.02 2.68 3.35 2.68
1.73 1.09 1.38 1.14


Figure 14
Means, Ranges and S.D.'s of Horizontal Jaw Positions Under Three
Conditions for 17 Sounds Selected From a Connected Speech Sample (N-4)


a i 6 L n W L j
N T HE E V E N IN G C 0 N NI E W AT C H E

4.52 4.52 3.35 4.36 4.02 4.02 4.02 4.19 4.36 3.02
3.35 3.35 3.35 2.68 2.68 4.69 4.02 2.01 4.02 4.69
1.76 1.76 1.64 1.28 1.22 1.97 1.81 0.84 1.73 2.08

ed --
4.19 3.68 3.18 4.19 4.36 5.19 5.02 4.19 4.69 3.02
3.35 2.68 2.68 2.01 2.01 3.35 3.35 2.68 3.35 4.02
1.48 1.16 1.38 0.84 0.86 1.38 1.39 1.14 1.64 1.59


Anesthetized
Mean
Range
Std.Dev.

Anesthetized
Mean
Range
Std.Dev.


ed an,
4.86
3.35
1.48








Analysis of Speech Tasks and Nonspeech Oral Movements


The measurements of jaw position obtained from the pro-

jected cinefluorographic frames (as outlined in Chapter Two)

have been summarized relative to five parameters of mandibu-

lar activity for the ten tasks. These parameters are: verti-

cal jaw displacement, horizontal jaw displacement, range of

vertical jaw movement, range of horizontal jaw movement, and

duration or length of production. For each of these five

parameters, measurements were recorded to represent mandibu-

lar activity throughout each task. These data were then sub-

jected to descriptive analysis, that is, mean and standard

deviation and to a test of statistical significance based

upon the analysis of a repeated measures design. The results

of the descriptive analysis and a summary of the analysis of

repeated measures with the mean square, sum of squares, de-

grees of freedom, and F statistic are presented in the ap-

pendix. An F value was considered significant when p4.05.

In the repeated measures design, each subject is ob-

served under each of the test conditions. This study repre-

sents a single factor repeated measures design where there

are three levels to the factor. Those levels are three test

conditions, that is, control, anesthesia, and anesthesia-

pressure.

The analysis of repeated measures provides an analysis

of variance in that the mean score for each condition is

compared with every other mean score. The analysis provides








a test of the statistical hypothesis (null hyphthesis),

Ho: all test condition means are equal. The alternate

hypothesis, H1 states that at least one pair of condi-

tion means differ significantly.

In order to determine between which pair of means

statistical significance exists, the Newman-Keuls Procedure

(Keppel, 1973) was utilized as a second step in the statis-

tical analysis. This procedure allows for multiple com-

parisons of the test condition means and indicates between

which pairs a statistical significance exists. A summary

of the Newman Keuls analysis, that is, the paired condi-

tion values, are presented for each of the ten tasks ana-

lyzed statistically, Tables 12 through 21.

The values for vertical and horizontal displacement

and the values for the range of motion are presented in

millimeters. The values for duration of production are

presented in number of frames. At a filming rate of 24

frames per second, the time between each frame is 40 milli-

seconds.


Nonspeech Oral Movements


Elevation of tongue tip

The amount of vertical mandibular displacement was

measured at three points during the movement, requiring

each subject to elevate his tongue tip. As listed in

Table 12, these measurements of vertical jaw displacement

were taken when the tongue contacted the alveolar ridge,










Table
Results of Newman
Condition Pairs
of Tongue Tip


12
Keuls Analysis:
for Measures
Elevation


Measures


Condition Pairs


Vertical Displacement
Tongue Contact
Tongue Release
Lowest Tongue

Horizontal Displacement
Tongue Contact
Tongue Release
Lowest Tongue

Range of Vertical Movement
Tongue Contact to Lowest
Tongue
Tongue Contact to Tongue
Release
Tongue Release to Lowest
Tongue


Range of Horizontal Movement
Tongue Contact to Lowest
Tongue
Tongue Contact to Tongue
Release
Tongue Release to Lowest
Tongue

Duration of Production
Tongue Contact to Lowest
Tongue
Tongue Contact to Tongue
Release
Tongue Release to Lowest
Tongue

p<.05


Normal/
Anesthesia
10.45/10.72
10.92/10.38
12.80/13.00


6.28/6.62
6.36/6.36
6.77/6.97


Normal/
Anesthesia-
Pressure
10.45/7.97*
10.92/7.24*
12.80/9.31*


6.28/6.12
6.36/5.86
6.77/6.28


2.51/2.26 2.51/2.34

1.17/1.51 1.17/1.43

2.43/2.68 2.43/2.60



0.34/0.67 0.34/0.84

0.59/0.76 0.59/0.84

0.67/1.09 0.67/0.92


Anesthesia/
Anesthesia-
Pressure
10.72/7.97
10.38/7.24*
13.00/9.31*


6.62/6.12
6.36/5.86
6.97/6.28



2.26/2.34

1.51/1.43

2.68/2.60



0.67/0.84

0.76/0.84

1.09/0.92


20.50/25.50 20.50/24.63 25.50/24.63

10.00/14.63*10.00/12.75 14.63/12.75

10.50/10.88 10.50/11.88 10.88/11.88


~








when the tongue just released contact with the alveolar

ridge, and when the tongue was in its lowest posture prior

to elevation for the following trial. Analysis of these

three vertical measures revealed that no significant dif-

ferences existed between the control and the anesthesia

condition, Table 12. However, further analysis revealed

that the vertical displacement of the jaw was reduced

significantly (p<.05) by the application of a light pres-

sure. The amount of horizontal displacement, measured at

these same three points, was not significantly altered under

either of the experimental conditions.

The range of mandibular movement in the vertical and

horizontal planes was calculated between tongue contact with

the alveolar ridge and at the point when the tongue was in

its lowest posture, between the time the tongue contacted the

alveolar ridge and released contact, and between the time the

tongue released contact and assumed its lowest posture. Sta-

tistical analysis of these data revealed no significant dif-

ferences between any of the three pairs of conditions.

Therefore, the range of jaw movement was not altered by anes-

thesia of the right auriculotemporal nerve, nor was the range

of movement altered by a subsequent application of pressure

to the left TMJ capsule.

The amount of time between these same three points was

calculated also. Although the duration of production appeared

increased by the experimental procedures, only the time re-

quired to complete the move from tongue contact to tongue re-

lease was significantly increased by the application of




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