Title: Esophageal and physiological effects of stress and relaxation
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Title: Esophageal and physiological effects of stress and relaxation
Physical Description: xii, 151 leaves : ill. ; 28 cm.
Language: English
Creator: Abrams, Kathleen Shea, 1941-
Publication Date: 1980
Copyright Date: 1980
 Subjects
Subject: Esophagus -- Motility   ( lcsh )
Stress (Physiology)   ( lcsh )
Clinical Psychology thesis Ph. D   ( lcsh )
Dissertations, Academic -- Clinical Psychology -- UF   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Thesis: Thesis--University of Florida.
Bibliography: Bibliography: leaves 145-148.
General Note: Typescript.
General Note: Vita.
Statement of Responsibility: by Kathleen Shea Abrams.
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Bibliographic ID: UF00099512
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000099094
oclc - 06927993
notis - AAL4544

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ESOPHAGEAL AND PHYSIOLOGICAL EFFECTS OF STRESS AND RELAXATION


BY

KATHLEEN SHEA ABRAMS




















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


1980

































Copyright 1980

by

Kathleen Shea Abrams






























This dissertation is dedicated, with love, to my husband

and to the memory of my father.















ACKNOWLEDGMENTS


The assistance and guidance of my supervisory

committee is gratefully acknowledged: Mark K. Goldstein,

Ph.D., chairman; Cynthia Belar, Ph.D.; Yvonne Brackbill,

Ph.D.; Edwin Cohen, Ph.D.; John Muthard, Ph.D.; Warren Rice,

Ph.D.; and Gerald Stein, M.D. Also gratefully acknowledged

is the assistance of Randy Carter, Ph.D., of the University

of Florida's Department of Statistics, and Steven Herman,

Ph.D., Donna Presley, and Arvey Rogers, M.D., of the Miami,

Florida Veterans Administration Medical Center.

















TABLE OF CONTENTS


Page

iv

vii


ACKNOWLEDGMENTS . . . . . . .

LIST OF TABLES . . . . . .


LIST OF FIGURES ...... . .. . . * * vii

ABSTRACT . . . . . . . .............. lx

INTRODUCTION . . . . ............ .. 1
Studies of the Esophagus ... . . . . 1
Representative Studies of Relaxation and Biofeedback
Affecting Biological Functioning . . . ... 7
Anxiety Measurement . . . . . * * * 9
Selection of a Stressful Stimulus Situation ... . 12
Selection of a Relaxing Stimulus Situation ... . 13

PURPOSE OF THE STUDY . . . . . . . .. 14

METHOD . . . . . . . . ... . . . 17
Subjects . . . . . . . ... . . 17
Experimental Design . . . . . . . ... 22
The Stress Situation . . . . . . ... 26
The Relaxation Situation . . . . . ... 27
The State-Trait Anxiety Inventory (STAI) . . .. 28
Physiological Variables . . . . . ... 29
Esophageal Variables . . . . . . ... 34
Procedures . . . . . . . . ... .. . 40
Data Compilation and Analysis . . . . . . 49


RESULTS . . . . . . . . .
Esophageal Variables . . . . .
Physiological Variables . . . .
Correlational Data . . . . . .

DISCUSSION . . . . . . . .
Esophageal Variables . . . . .
Physiological Variables . . . . .
Correlational Data . . . .
Comparison of Present Study with Previous
Conclusions . . . . . . . .


. . . 54
. . . 54
. . . 61
. . . 68

. . . 72
. . . 72
. . . 90
. . 95
Studies 97
. . . 104


I












APPENDIX A.

APPENDIX B.


LETTER TO SUBJECTS . . . . . .

TRANSCRIPT OF INTELLECTUAL ACHIEVEMENT
TEST . . . . . . . . .


APPENDIX C. ESOPHAGEAL TRACINGS: CHANNELS 1-4

APPENDIX D. ESOPHAGEAL TRACINGS: CHANNELS 5-7

APPENDIX E. INFORMED CONSENT FORM . . . .

APPENDIX F. SCORED ESOPHAGEAL TRACINGS . . .

APPENDIX G. TABLES 12 AND 13 . . . . .

NOTE . . . . . . . . . . .

REFERENCES . . . . . . . . . .

BIOGRAPHICAL SKETCH . . . . . . .


Page

110


S 112

S 116

. 118

S 119

S 123

. 125

S 144

S 145

. 149















LIST OF TABLES


Table Page

1. Measurement of Dependent Variables . . .. 24

2. Main Effects Tested for in ANOVA for Esophageal
Variables . . . . . . . . ... 52

3. Summary of Analyses of Variance for Esophageal
Variables: Mean Squares . . . . .. 55

4. Summary of Duncan's Tests for Esophageal
Variables: Means . . . . . . ... .57

5. Main Effects Tested for in ANOVA for Physiologi-
cal Variables . . . . . . . ... 62

6. Summary of Analyses of Variance for Physiologi-
cal Variables: Mean Squares . . . ... 63

7. Summary of Duncan's Tests for Physiological
Variables: Means . . . . . . ... 64

8. Significant Esophageal-Physiological Correla-
tions for Group by Order Combinations ... 69

9. Comparison of Esophageal Variables During Stress
and During Relaxation . . . . . ... 75

10. Comparisons of Esophageal Variables Between the
HA and LA Groups . . . . . . ... 80

11. Comparisons of Esophageal Variables Between the
Early Relaxation and Early Stress Orders . 84

12. Esophageal Variable Means and Standard Deviations
by Treatment Situation, Site, and Group by
Order Combinations . . . . . ... 125

13. Physiological Variable Means by Treatment
Situation and Group by Order Combinations . 137















LIST OF FIGURES


Figure Page

1. Autonomic innervation of the esophagus . . 6

2. Subject with forehead EMG electrodes, nasogastric
tube, and throat collar in place . . .. 31

3. Autogen 1700, 2000b, and 3000 for measuring
physiological variables . . . . ... 33

4. Temperature probe taped to subject's hand and
skin conductance sensors attached to subject's
fingers . . . . . . . . . 33

5. Autogen 5600 and P-5000 Alphanumeric Printer for
computing and recording means and standard de-
viations of physiological data . . . .. 37

6. Four-lumen, flexible nasogastric tube and
swallow-recording throat collar . . . .. 37

7. Hewlett-Packard 7758A eight-channel writer-
recorder for recording esophageal data . . 39

8. Subject in supine position with recording equip-
ment in place . . . . . . . ... 43

9. Graph of mean hand temperature for Early
Relaxation and Early Stress subjects ... . 93

10. Esophageal tracings: Channels 1-4 . . ... .116

11. Esophageal tracings: Channels 5-7 . . .. .118

12. Scored esophageal tracings . . . . ... 123


viii















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

ESOPHAGEAL AND PHYSIOLOGICAL EFFECTS OF STRESS
AND RELAXATION

By

Kathleen Shea Abrams

August 1980

Chairman: Mark K. Goldstein
Major Department: Psychology

To determine whether esophageal motility changes occur

in response to stress and to relaxation, an experiment was

conducted employing 28 healthy medical and premedical

students. Results of previous studies indicated that stress

may increase esophageal motility in healthy adults and symp-

tomatic individuals with esophageal motor disorders. The

present study defined stress as an oral intellectual achieve-

ment test and relaxation as taped autogenic relaxation in-

structions. Subjects were assigned to the High Anxiety (HA)

group or to the Low Anxiety (LA) group on the basis of their

anxiety trait scores on the State-Trait Anxiety Inventory.

HA and LA subjects were randomly assigned to either the

Early Relaxation (ER) order, i.e. relaxation presented prior

to stress, or to the Early Stress (ES) order, i.e. stress

presented prior to relaxation. Esophageal contractions were

measured simultaneously at four sites in the body of the









the esophagus. At each site, four esophageal variables were

measured: frequency and intensity of swallow-related con-

tractions (FrSw, InSw), and frequency and intensity of

spontaneous contractions (FrSp, InSp). Concomitant mea-

surement of physiological variables occurred: frontalis EMG

mean and standard deviation (EMGM, EMGSD), fingertip skin

conductance level mean and standard deviation (SCLM, SCLSD),

and hand temperature mean and standard deviation (TEMPM,

TEMPSD). An experimental session was comprised of seven

10-minute phases: Phase 1, physiological baseline; 2, stan-

dard esophageal manometry (a diagnostic procedure to deter-

mine normalcy of esophageal motility); 3, recovery from

manometry; 4, relaxation for ER subjects and stress for ES

subjects; 5, recovery from either stress or relaxation;

6, stress for ER subjects and relaxation for ES subjects;

7, recovery from either stress or relaxation. For each of

the dependent variables, a repeated measures ANOVA tested for

significant (p<.05) main effects and interactions, followed

by the Duncan's multiple range test to identify significant

(p.05) differences between means.

It was found that (1) SCLM increased significantly dur-

ing stress and decreased significantly during relaxation,

suggesting that the stress situation was sufficiently stress-

ful and the relaxation situation sufficiently relaxing to

affect biologic functioning; (2) no significant differences

in InSp or in InSw occurred during stress, compared with


j









relaxation, at any esophageal site; (3) the LA group showed

a significantly lower FrSp during relaxation than the HA

group at two esophageal sites; (4) the HA and LA groups

showed no significant differences during stress on any mea-

sured esophageal variable at any site; (5) without respect

to site, InSp significantly increased during recovery from

stress and recovery from relaxation, compared with stress and

relaxation, respectively; (6) FrSp significantly increased

during recovery from stress, compared with stress, at one

site, and during recovery from relaxation, compared with

relaxation, at one other site; and (7) ER subjects had a

significantly higher InSw than ES subjects, without respect

to treatment situation or esophageal site.

Conclusions were that (1) no important esophageal

motility changes occurred during stress or relaxation;

(2) the HA and LA groups showed few significant differences

in esophageal motility; (3) ER and ES subjects may have been

initially different in InSw, but were comparable on other

variables; (4) there may be delayed InSp and FrSp responses

to stress and relaxation; (5) the apparent delayed responses

are not significantly different to stress than to relaxa-

tion; (6) the esophagus may respond similarly to a variety

of stimuli situations; and (7) the possibility that stress

may significantly change the esophageal motility of symp-

tomatic individuals is not ruled out.









It is suggested that future research determine the

effects of a variety of stimuli, not solely stress, on the

esophageal functioning of symptomatic individuals.















INTRODUCTION


Studies of the Esophagus

Research about the effects of stress on the gastro-

intestinal system has primarily focused on the stomach and

the intestines (Sleisinger & Fordtran, 1978; Grace, Wolf,

& Wolff, 1951). A small body of literature, both research

and clinical, suggests that the esophagus (or "gullet")

reacts to a variety of noxious stimuli of physical or psycho-

logical origin (Earlam, 1975). For instance, diffuse

esophageal spasm and achalasia, both of which are esopha-

geal disorders characterized by swallowing difficulty and

non-propulsive peristalsis, are thought to be exacerbated by

stress (Pope, in Sleisinger & Fordtran, 1978; Cohen &

Snape, 1977). However, investigations of the effects of

stress on esophageal functioning have had serious methodo-

logical flaws, such as inadequate pre-stress measures of

esophageal functioning and a lack of objective, standardized

stressful stimuli, e.g. Faulkner, 1940a; Faulkner, 1940b;

Wolf and Almy, 1949; Nagler and Spiro, 1961; Rubin, Nagler,

Spiro and Pilot, 1962. Consequently, research to date has

not adequately investigated the possible effects of stress

on esophageal functioning. Moreover, the effects of relaxa-

tion on the esophagus have been neglected. An intensive

literature search revealed no studies in this area.

1










The importance of investigating the effects of stress

and of relaxation on the esophagus derives, in part, from

the lack of sound research in the area. Moreover, con-

siderable difficulty has been noted in attempts to treat

successfully some esophageal motor disorders, like diffuse

esophageal spasm, with usual medical treatments like medica-

tion and rest (Pope, in Sleisinger & Fordtran, 1978). Symp-

toms of these disorders may be mild or may be severe enough

in some cases to result in hospitalization and surgery (Pope,

in Sleisinger & Fordtran, 1978). The most common symptoms

of which patients complain are dysphagia, or difficulty in

swallowing, and discomfort, but some patients experience

intense pain, apparently from severe esophageal spasms that

may mimic a heart attack (Pope, in Sleisinger & Fordtran,

1978).

Faulkner (1940a, 1940b) was among the first to report

that "the presence of esophageal spasm . was determined

by emotional factors" in symptomatic patients (1940a, p. 140).

Faulkner (1940b) subsequently reported similar findings with

13 other symptomatic patients. However, both these studies

lacked adequate controls for the investigator's expectations

and for the possible hyperreactivity of a symptomatic

esophagus to any novel stimulus situation, such as the one

used in these studies, i.e. insertion of a tube into the

esophagus during an interview about the patient's troubles

(Faulkner, 1940a, 1940b). Subsequent studies (Wolf & Almy,









1949; Rubin et al., 1962; Nagler & Spiro, 1961) were simi-

larly flawed, using circular reasoning to make post-facto

judgments about the stressful nature of the interviewer's

questions on the basis of the presence or absence of

esophageal spasms. Rubin et al. (1962) studied asymptomatic

paid volunteers with no history of esophageal disorder, and

suggested that there may be a relationship between stress

and esophageal motor dysfunction "in some healthy young

adults" (1962, p. 175). These interesting findings must be

viewed cautiously, for reasons already noted, but also be-

cause the investigator's presentation of stressful stimuli

was not standardized from one subject to the next, or from

one examination to the next of the same subject. As

recently as 1978, a reviewer of treatment studies of

gastrointestinal disorders, including esophageal disorders,

called for experiments to investigate clinical impressions

that symptoms "often occur in response to stressful environ-

mental events" (Whitehead, 1978, p. 383).

Since 1978, one experimental study has found that non-

propulsive, or spontaneous, esophageal contractions occur

in response to intense acoustical stimuli (Stacher,

Steinringer, Blau, & Landgraf, 1979). The sample was com-

prised of 16 young adults with no known history of

esophageal disorder. Fourteen of the 16 subjects developed

nonpropulsive, spontaneous esophageal contractions in

response to a 95-decibel (dBA) tone (Stacher et al., 1979).









The investigators reported that both the frequency and the

intensity of these contractions increased as stimulus in-

tensity increased from 65 to 80 to 95 dBA. Contractions were

considered to be stimulus-induced if the onset of a contrac-

tion occurred within two seconds after stimulus onset. Con-

comitant monitoring of heart rate revealed "no definite rela-

tionship between the occurrence of an esophageal contractile

response and a decelerative or accelerative heart rate

response" (p. 240). No other physiological variable was

monitored. The study suggests that certain kinds of sensory

stimuli, processed by the central nervous system, have the

potential for altering esophageal motor activity in indi-

viduals without a history of esophageal disorders.

The physiological and clinical significance of sponta-

neous esophageal contractions is based on their frequency

and intensity (Pope, in Sleisinger & Fordtran, 1978).

Healthy individuals show low frequency, low intensity

spontaneous contractions whereas individuals with certain

types of esophageal disorders may show contractions at a

much higher rate and amplitude (Pope, in Sleisinger &

Fordtran, 1978). At high frequencies and intensities, these

contractions may be referred to as esophageal spasms. To

comprehend more fully the nature and significance of spon-

taneous contractions, it is necessary to understand the

basics of normal esophageal functioning. "The function of

esophagus is to expedite the passage of swallowed food into





5



the stomach by nicely regulated peristaltic contractions"

(Wolf & Goodell, 1968, p. 66). The esophagus, a muscular,

hollow tube approximately 40 to 45 centimeters (16 to 17

inches) long, is comprised of skeletal muscle in its proxi-

mal third and smooth muscle in its distal two-thirds

(Mechanisms of Disease, 1979). Its proximal end begins at

the back of the mouth and its distal end terminates where

the esophagus joins the stomach. The sympathetic and para-

sympathetic nervous systems innervate the esophagus (Mecha-

nisms of Disease, 1979). The motor nerve supply to the

esophagus (Figure 1) comes from the vagus nerve and the spinal

accessory nerve (Pope, in Sleisinger & Fordtran, 1978).

"The latter innervates the high cervical portion of the

esophagus; the vagus supplies most of the rest of the esopha-

geal musculature" (Pope, in Sleisinger & Fordtran, 1978,

p. 498). Therefore, the vagus nerve is "probably important

in coordinating the striated and smooth muscle portion of

the esophagus" (Pope, in Sleislinger & Fordtran, 1978, p.

505). Three separate zones of the esophagus have been

identified: (1) the upper sphincter zone, composed of

striated muscle; (2) the body of the esophagus, composed of

smooth and striated muscle; and (3) the esophagastric area,

composed of smooth muscle, in which the lower esophageal

sphincter is located (Pope, in Sleisinger & Fordtran, 1978).

Pope in Sleisinger and Fordtran (1978) described normal

esophageal motor functioning as follows:


i













Sympathetic chain


Vagus


Figure 1. Autonomic innervation of the esophagus.


- T-6



Greater
splanchnic n










Muscular events in the body of the esophagus are most
commonly set in motion by a swallow (primary peristal-
sis). A moving ring contraction sweeps down the
esophagus from the upper sphincter to, but not through,
the lower esophageal sphincter zone. . If multiple
recording tips are used [on a multiple lumen catheter,
or tube, passed into the esophagus through the nose
or mouth], the progressive nature of the moving ring
contraction will be recognizable. . Several factors
influence the amplitude and occurrence of peristalsis.
There is much variance in amplitude of a dry swallow
[no ingested fluid] when recorded from the same site
in the same individual. Also, amplitudes vary con-
siderably from one end of the esophagus to the other,
and between normal individuals. Values are quite con-
stant for the same individual, however, when studied
on different days. (p. 507)

By comparison, examination of esophageal functioning in

individuals with diffuse esophageal spasm reveals

normal functioning of the upper esophageal sphincter
and upper third of the esophagus. However, in the
lower two-thirds, the deglutition [swallowing] occa-
sionally causes a normally progressive peristaltic
wave, but, more frequently, a simultaneous contrac-
tion occurs [i.e. contractions occur at more than one
esophageal site simultaneously, rather than progres-
sively]. The contractions in the lower two-thirds
tend to be of higher amplitude [than normal]. . .
Pharmocologic relief of the pain and dysphagia
[difficulty in swallowing] of diffuse spasm has been
uniformly disappointing. (Pope in Sleisinger &
Fordtran, 1978, p. 531)

Contractions may also occur spontaneously, without swallow-

ing, in normal individuals, but more frequently in indi-

viduals with diffuse spasm (Cohen, 1979).


Representative Studies of Relaxation and Biofeedback
Affecting Biological Functioning

Although no studies of the effects of relaxation on

esophageal functioning were found, one study of the effects

of biofeedback on reflux, or "heartburn," reported success in









changing lower esophageal sphincter pressures in the desired

direction with three normal subjects and six patients having

a history of esophageal reflux (Schuster, Nikoomanesch, &

Wells, 1973). The findings reported by Schuster et al. (1973)

suggest that psychological treatment methods might have some

potential in the treatment of certain esophageal disorders.

Muscle relaxation has been noted as an important treatment

modality for a number of physical disorders thought to be

stress-induced or stress-exacerbated (Tarler-Benlolo, 1978).

A recent review of studies of physiological correlates of

relaxation training summarized the studies' findings as

follows: "Relaxation is associated with decreases in respi-

ratory rate, heart rate and blood pressure; increases in

peripheral skin temperature; lowered levels of frontalis

EMG activity; a decrease in skin conductance level" (Tarler-

Benlolo, 1978, p. 730). Comparative studies of various re-

laxation training methods have reported that the methods

studied seem to be equally effective in treating tension

headaches, pain syndromes, insomnia,and functional bowel

disorders (Tarler-Benlolo, 1978). However, the majority of

these studies have been criticized as poorly designed, with-

out adequate follow-up or standardization of technique

(Tarler-Benlolo, 1978; Jacobson, 1978). Additionally,

Johnson (1978) found no significant differences in heart

rate between relaxation and pseudotreatment groups selected

on the basis of self-reported test anxiety.









In summary, then, evidence for physiological effects

specific to relaxation is inconsistent. Furthermore, studies

comparing relaxation with biofeedback for treatment of some

stress-related disorders have yielded conflicting results

about the superiority of one method over the other (Tarler-

Benlolo, 1978). Despite the weaknesses of many studies of

relaxation treatment, Tarler-Benlolo (1978) concluded that

there are sufficient studies that appear methodologically

sound to justify further investigation of relaxation as a

treatment method. Therefore, the present study investigated

the effects of relaxation training on several esophageal and

physiological variables, specifically, forehead EMG, hand

temperature and fingertip skin conductance level. As pre-

viously noted, the effects of relaxation training on these

physiological variables, except esophageal functioning, have

been studied in previous research but with inconsistent

results.


Anxiety Measurement

Findings of some anxiety studies indicate that indi-

viduals rated as highly anxious on self-report measures may

respond to stress with greater behavioral and physiological

changes than do individuals rated as less anxious (O'Neil,

1970; O'Neil, Hansen, & Spielberger, Note 1; O'Neil,

Spielberger & Hansen, 1969). However, the correlation be-

tween physiological and self-report measures of anxiety has

generally been low (Schachter, in Spielberger, 1966). While


j










it can be assumed that reports of anxiety are related both

to physiological and cognitive changes, physiological changes

are thought to be a necessary condition but may not be a

sufficient condition for changes in self-reported anxiety

(Schachter, in Spielberger, 1966). Nonetheless, O'Neil,

Spielberger and Hansen (1969) found that college students'

systolic blood pressure and their scores on the State scale

of the State-Trait Anxiety Inventory (STAI) covaried with

the degree of difficulty encountered on a learning task. In

a follow-up study by the same investigators (O'Neil, Hansen,

& Spielberger, Note 1), students with high scores on the

STAI State scale showed greater performance impairment on a

learning task than did those with low scores on the same

measure. Hall (1970) found similar results in a study of

156 male high school seniors. Therefore, some evidence

suggests greater behavioral and physiological changes in

those described as highly anxious than those described as

less anxious on the STAI.

The STAI is comprised of separate self-report scales for

measuring state anxiety and trait anxiety, considered to be

two different types of anxiety (STAI Manual, 1970). The

STAI is a brief questionnaire titled the "Self-Evaluation

Questionnaire" on the answer form itself, which college

students generally complete in fewer than 10 minutes (STAI

Manual, 1970). Trait and State scales are scored separately,

providing two scores for each subject. The STAI norms for









college students are based on approximately 1,500 Florida

undergraduate college students' responses (STAI Manual,

1970). Several studies that used the STAI to measure

anxiety levels before, during, and following stress provide

estimates of the instrument's validity as a measure of a

relatively consistent behavior pattern, termed trait

anxiety. For instance, Auerbach (1973) compared the effects

of "success feedback" and of "failure feedback" during an

intelligence test on college students with high anxiety

trait scores and on those with low anxiety trait scores on

the STAI. Differences between high and low trait subjects

for anxiety state scores were greatest in the "failure feed-

back" condition (Auerbach, 1973). McAdoo (1971) found

similar results in a study of the effects of failure feed-

back on students' anxiety levels while performing an intel-

lectual task. The findings of Auerbach (1973) and McAdoo

(1971) suggest that individuals with high trait anxiety

report greater state anxiety under stress than do subjects

with low trait anxiety. The findings of O'Neil (1970)

suggest that high trait anxiety subjects not only report

greater anxiety under stress, but also experience more

anxiety than low trait anxiety subjects. Consequently, the

present study chose two groups of students-one group with

high trait anxiety and the other with low trait anxiety, as

measured by the STAI-in order to maximize potential dif-

ferences between the two groups during the study's stressful

stimulus situation.









Selection of a Stressful Stimulus Situation

Academic and intellectual examinations appear to result

in identifiable physiological changes associated with stress.

Dreyfuss and Czaczkes (1959) documented physiological changes

in blood cholesterol and uric acid thought to be associated

with the stress experienced by medical students during

academic examinations. Schiffer, Hartley, Schulman, and

Abelmann (1976) investigated the effects of stress associated

with an intellectual performance task on executives and non-

executives, both with and without ischemic heart disease.

Of the total 43 subjects, 33 were considered executives. The

executives were divided into three groups: control, angina

with a history of hypertension, and angina without a history

of hypertension. Both of the angina groups of executives

responded to the intellectual performance task with higher

heart rates during the task than did the nonexecutives with

angina and the control group of executives. Subjects' post-

task self-reports also suggested that the executives with

angina had experienced greater feelings of anxiety than had

the nonexecutives with angina. Taken together, the findings

of Schiffer et al. (1976) and of Dreyfuss and Czaczkes

(1959) indicate that individuals with high achievement moti-

vation and behavior, like medical students and executives,

may demonstrate a variety of physiological changes related

to the stress of academic or intellectual examination.









Therefore, the present study selected an intellectual

examination task as its stressful stimulus, and chose as

subjects medical and premedical students because of their

presumed high achievement motivation.


Selection of a Relaxing Stimulus Situation

The choice of a relaxation situation was based on

several factors-ease of administration, standardization, and

prior results. A recent review by Tarler-Benlolo (1978) of

relaxation treatment studies reported that autogenic train-

ing methods appear to achieve the same type and degree of

physiological changes as other relaxation methods, such as

progressive muscle relaxation. Autogenic training is a term

applied to a self-induced relaxation method developed by

Johannes Shultz, a German psychiatrist, in the 1960s (Tarler-

Benlolo, 1978). The autogenic method focuses on achieving

feelings of warmth and heaviness in the extremities, regu-

lation of cardiac and respiratory activity and other related

physiological changes thought to be associated with relaxa-

tion (Tarler-Benlolo, 1978). The autogenic training method

has been adapted and standardized on a series of audiotapes

developed by Budzynski (1974) for patients' use at home.

Evidence for the effects of autogenic relaxation training on

several of the physiological variables of interest in the

present study,specifically forehead EMG and hand temperature,

is found in Cleaves (1971).














PURPOSE OF THE STUDY


The purpose of the present study was to investigate the

esophageal and physiological effects of stress and relaxa-

tion in healthy adults. The study was exploratory, in part,

in order to investigate whether psychologically-induced

stress and relaxation have any measurable effects on normal

esophageal functioning. Since previous studies had sug-

gested that some esophageal variables are more likely than

others to react to stress, the present study investigated

certain hypotheses about the nature and direction of changes

in esophageal functioning in response to stress.

It was hypothesized that stress would increase the fre-

quency and intensity of spontaneous contractions, and would

also increase the intensity of swallow-related (propulsive)

contractions. It was not known whether any change might

occur in the frequency of swallow-related contractions, be-

cause of a lack of literature on that topic.

It was not known whether any change would occur in any

of the esophageal variables-frequency and intensity of

spontaneous contractions, frequency and intensity of swallow-

related contractions-in response to relaxation, because of

similar lack of literature on that subject. However, if

changes did occur in response to relaxation, it was expected









that those changes would take the form of decreases in the

frequency and intensity of spontaneous contractions, and

decreases in the intensity of swallow-related contractions,

compared with baseline levels. Once again, no assumption was

made about the nature or direction of any change in the

frequency of swallow-related contractions.

It was hypothesized that highly anxious individuals

would be more likely to demonstrate stress-related and

relaxation-related changes in esophageal functioning than

would less anxious individuals.

It was further expected that the lower two-thirds of

the esophagus would be more likely than the upper third to

show changes associated with stress and relaxation. This

expectation derived from previously discussed literature

about the greater incidence of esophageal changes in the

lower two-thirds of the esophagus shown under stress by some

patients with diffuse esophageal spasm.

A previous study of esophageal response to an intense

auditory stimulus (Stacher et al., 1979) monitored heart

rate and found no significant relationship between heart

rate and esophageal contractions. Therefore, the present

study selected for monitoring three other physiological

variables-forehead EMG, hand temperature,and fingertip skin

conductance-discussed in the literature as being sensitive

to stress and to relaxation. No assumption was made about

whether changes in any of these physiological variables









would be correlated with changes in any of the esophageal

variables. Nonetheless, the present study investigated

whether significant correlations might occur between esopha-

geal and physiological variables.

It was hypothesized that mean forehead EMG would in-

crease, mean hand temperature would fall, and mean skin con-

ductance level would rise in response to stress compared

with baseline levels. In response to relaxation, it was

expected that changes in the opposite direction would occur

for each of the physiological variables. It was further

expected that the variability of each of the physiological

variables would be lower during either stress or relaxation

than it would be during baseline.

It was expected that highly anxious individuals would

be more likely than less anxious individuals to demonstrate

changes in the physiological variables in response to stress

and to relaxation.

Finally, the present study formulated no hypothesis

about the possible effects of the order in which the stress

situation and the relaxation situation would be presented

to subjects. The present study varied the order of presen-

tation in order to control for possible differential effects

of presenting one situation prior to the other.














METHOD


Subjects

Studies were performed on 28 healthy young adults, 24

men and 4 women, all of whom were medical or premedical

students at the University of Miami. None of the subjects

reported any history of esophageal disorder. Upon examina-

tion by standard manometry, a method for measuring esophageal

contractions, all subjects were found to have esophageal

functioning within the normal range.

A sample of subjects was initially selected on the basis

of scores on the STAI Trait scale. Two groups were chosen

from those who completed the questionnaire: a High Anxiety

(HA) group and a Low Anxiety (LA) group. To select the HA

group, a cutoff score of 42 was used, representing the 68th

percentile for males and the 73rd percentile for females,

based on undergraduate college norms (STAI Manual, 1970).

No specific norms for medical or for premedical students were

found for the STAI. To select the LA group, a cutoff score

of 30 was used, representing the 24th percentile for males

and the 15th percentile for females, based on the same

undergraduate norms as for the HA group (STAI Manual, 1970).

The STAI was administered to freshmen, sophomore, and

junior medical students at the end of a regular class









session. Students had already received a written request

signed by the Chief of the Gastroenterology Section of the

Miami Veterans Administration Medical Center (V.A.M.C.)

requesting their cooperation in completing the questionnaire.

The experimenter explained to the students that the adminis-

tration of the questionnaire was the first stage of a coopera-

tive study between the Psychology Service and the Gastroen-

terology Section of the Miami V.A.M.C. The experimenter,

with the assistance of the esophageal technician, distri-

buted the questionnaires, titled "Self-Evaluation Question-

naire," to all students in the classroom and collected com-

pleted questionnaires as students exited from the classroom.

Students had already been informed that their scores would

be confidential, and that those who qualified for the next

stage of the study would be notified by mail. A total of

200 medical students completed the questionnaire. Subse-

quently, the questionnaire was administered to approximately

80 undergraduate junior and senior premedical students be-

cause a larger subject pool was required to identify a suf-

ficient number of subjects qualified and willing to partici-

pate in the second stage of the study.

The decision to use medical and premedical students as

subjects was based, in part, on availability and on an assump-

tion of their interest and willingness to participate as paid

volunteers in a medically-related study. However, this

assumption may have been in error. For instance, of an









initial group of 40 medical students whose questionnaire

scores qualified them for further participation in the study,

only four responded to a written invitation to participate

further, accompanied by an offer of fifty dollars compensa-

tion for approximately two and a half hours of their time

(Appendix A). Students who had not responded to the invita-

tion within one week's time were contacted by phone by the

experimenter. Many of these students reported to the experi-

menter that they were unwilling to allow a nasogastric tube,

used for measuring esophageal contractions, to be passed

into their esophagus. Some of these students reported that

they had witnessed tubes being passed into patients' esophagi,

and they felt that it was a very uncomfortable procedure.

Reassurance about the minimal discomfort that other subjects

had experienced in similar studies was successful in chang-

ing the decision of only one student who had been initially

unwilling to participate.

Subsequent to the phone contacts with reluctant but

otherwise qualified subjects, the reimbursement fee was raised

from the initial fifty dollars to one hundred dollars. The

STAI was then administered to another 120 medical students,

nearly half of whom qualified for further participation in

the study. Twenty of those 56 qualified students responded

to the written invitation accompanied by an offer of one

hundred dollars. Of those 20, however, all but 2 were in the

Low Anxiety (LA) group. High Anxiety (HA) subjects were









apparently unwilling to participate further, even for greater

financial compensation.

The initial intention had been to select subjects on

the basis of two measures: their STAI score and their base-

line measures of forehead EMG, hand temperature and skin

conductance. Students with concordance on the STAI and at

least two of the three physiological measures, i.e. high-

high or low-low, would then qualify for further participa-

tion in the study.

Although the correlation between physiological and

self-report measures of anxiety has generally been low, as

previously discussed, the use of a self-report measure alone

as an indicator of a subject's anxiety level seemed un-

justified in a study whose purpose was to investigate physio-

logical variables. On the other hand, the use of any or all

of the physiological variables as measures of anxiety with-

out a self-report measure seemed equally unjustified be-

cause of contradictory evidence, previously discussed, of

the correlations of physiological changes to various anxiety

levels. Therefore, the initial intention of the present

study was to require agreement between self-reports and

physiological measures because neither one alone seemed a

sufficient index of anxiety. It was assumed that the use of

a double screening procedure to select a sample of approxi-

mately 30 qualified subjects would require a large subject

pool of willing participants. However,.when so few students









volunteered for participation in the study even in response

to increased compensation, the double screening procedure was

replaced with a single screening procedure, the STAI or self-

report measure, as described.

Even with this change to a single screening procedure,

the number of medical students willing to participate beyond

the completion of the STAI was insufficient to provide the

sample size intended for the study. Therefore, the STAI was

administered to approximately 80 junior and senior premedical

students in order to increase the size of the subject pool.

In this way, a sample of 28 qualified students was selected,

with an equal number in the HA and LA groups, as planned. It

should be noted that HA students generally responded only

after two written invitations and a follow-up phone call.

Of a total of 36 subjects, both HA and LA, who were

scheduled to participate in the second stage of the study,

eight were unable to complete the study past Phase 1, the

physiological baseline. These eight subjects were unable

to have the nasogastric tube passed through the nose or

mouth into the esophagus. No data exist in the literature

on the incidence of this difficulty in esophageal research.

However, the esophageal technician who performed the

esophageal measurement procedures estimated that the inci-

dence of difficulty in the present study was substantially

higher than in other esophageal studies she had performed

with medical students as subjects.









The final sample of 28 subjects represents approximately

10% of the student population to whom the STAI was adminis-

tered. The difficulties encountered in completing the sample

are not likely to bias the representativeness of the sample,

because all subjects met the selection criteria and all had

esophageal functioning within the normal range. The group

of 8 subjects who were unable to complete the study was

evenly divided between females and males, and between HA and

LA categories. Therefore, this group of subjects did not

differ significantly from the sample on the basis of the HA:

LA ratio, but did differ on the basis of the sex ratio.

Females comprised 50% of the dropped subject group but only

14% of the final sample. The circumference of the four-

lumen nasogastric tube appeared to have been too large for

more females than males in the present study.


Experimental Design

The study was designed to investigate the effects of two

independent variables-an orally-presented "stress quiz" and

orally-presented relaxation introduction-on two types of

dependent variables, esophageal and physiological. Each of

the 28 subjects participated individually in one experimental

session, the second stage of the study following the adminis-

tration of the STAI. An experimental session was of approxi-

mately two and a half hours duration. Prior to the experi-

mental session, subjects had been assigned either to the

HA or to the LA group on the basis of their STAI Trait Scale









score, as previously described. Subjects in both groups

were then randomly assigned either to an Early Stress/Late

Relaxation order (referred to as the Early Stress order for

the remainder of this report) or to the Early Relaxation/

Late Stress order (referred to as the Early Relaxation

order). In this way, half of the HA group and half of the

LA group were randomly assigned to the Early Stress order,

and half of each group was randomly assigned to the Early

Relaxation order.

An experimental session consisted of seven 10-minute

phases as follows: Phase 1, Physiological Baseline; Phase 2,

Standard Manometry (initial measurement of esophageal func-

tioning to determine normalcy); Phase 3, Recovery from

Manometry; Phase 4, the Stress condition for subjects in the

Early Stress order and the Relaxation condition for subjects

in the Early Relaxation order; Phase 5, Recovery; Phase 6,

the Relaxation condition for subjects in the Early Stress

order and the Stress condition for subjects in the Early

Relaxation order; and Phase 7, Recovery. Table 1 shows the

seven phases of the multiple baseline, two-experimental

treatment, group design.

Throughout the course of the study, the esophageal tech-

nician was responsible for taking measurements of esophageal

variables and the experimenter was responsible for the mea-

surements of physiological variables. The technician, the

experimenter, and the subject were the only persons present










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during an experimental session. The measurements of physio-

logical variables-forehead EMG, hand temperature, and

fingertip skin conductance level-were recorded continuously

from Phase 1 through Phase 7. Measures of esophageal

variables were recorded continuously from Phase 2 through

Phase 7. The nasogastric tube for measuring esophageal

variables was introduced into a subject's esophagus at the

beginning of Phase 2. During Phase 2, the normalcy of the

esophagus was determined by standard manometry. Phase 3

marked the beginning of continuous measurement of esophageal

functioning in the body of the esophagus. The physio-

logical and psychological effects of the tube's introduc-

tion were not known in advance because of a lack of litera-

ture on the topic. However, the experimenter assumed that

the experience was likely to be mildly to moderately stress-

ful for most subjects. Therefore, Phase 1 served as a pre-

nasogastric tube physiological baseline.


The Stress Situation

In the present study, stress was defined as the adminis-

tration of a taped, oral intellectual achievement test under

timed conditions (Appendix B). Taped instructions preceding

the test informed the subject that results of previous

research indicated that above average performance on the quiz

accurately predicts future success in medical school. Other

parts of the taped instructions were similarly designed to









increase the subject's motivation and anxiety about the

test. For example, the subject was informed that his or her

overall performance would not be disclosed until the comple-

tion of the experimental session. To increase further the

anxiety-producing characteristics of the stress condition,

subjects received "failure feedback" about their performance

on the first part of the quiz, after Question 17. As sug-

gested by the findings of Auerbach (1973) and McAdoo (1971),

failure feedback tends to increase anxiety of low anxiety

and of high anxiety subjects, though the latter group is

likely to show a greater increment in measured anxiety on a

self-report questionnaire.

In summary, five characteristics of the stimulus situa-

tion designed to induce stress were the use of an intellec-

tual achievement task requiring answers whose correctness

was difficult for subjects to judge; instructions describing

task performance as a predictor of future academic success;

oral administration; failure feedback; and the requirement

of oral answers to an audience, one member of whom scored

their correctness.

The Relaxation Situation

The relaxing stimulus situation was operationalized as

the presentation of audiotaped relaxation instructions focus-

ing on the upper and lower extremities. The tape is part of

an autogenic self-instruction relaxation training program

called the "Relaxation Training Program," developed for home

use by patients (Budzynski, 1974). Tape 4, "Limb Heaviness









and Warmth," as narrated by Judith Proctor, was used in the

present study. On this tape, the narrator instructs the

subject to use mental imagery to achieve feelings of warmth

and heaviness in the arms and legs. Tape 4 was chosen be-

cause of its focus on hand temperature, one of the physio-

logical variables of interest in the present study, and

because of evidence suggesting that hand temperature increases

are related to heightened muscle relaxation (Kappes, 1979).

Finally, the present study used a relaxation training tape

narrated by a female because the taped quiz used in the

stress condition also had a female narrator.


The State-Trait Anxiety Inventory (STAI)

The STAI is a widely-used self-report questionnaire with

two scales, a State Anxiety Scale and a Trait Anxiety Scale

(STAI Manual, 1970). The present study selected the STAI to

identify subjects for the HA and LA groups because the STAI

can be quickly administered (approximately 10 minutes for

college students), its norms are appropriate for the research

population, and it provides a score, the trait anxiety score,

that appears to measure a relatively consistent behavior

pattern. Additionally, test-retest correlations for the

Trait Anxiety Scale range from .73 to .86, whereas those

for the State Anxiety Scale are significantly lower (STAI

Manual, 1970).

The STAI Trait Anxiety Scale consists of 20 statements

asking a subject to describe how he or she generally feels










(STAI Manual, 1970). By comparison, the STAI State Anxiety

Scale asks for a description of feelings at the time a sub-

ject is completing the 20 questions comprising that scale

(STAI Manual, 1970). In a study of the relationship of STAI

scores to subjects' reactions to stressful stimuli, Hodges

and Felling (1970) found that the STAI Trait Anxiety Scale

correlated significantly with three types of situations that

all involved psychologically induced stress, specifically,

threats of academic or social failure, but not with situa-

tions involving pain or physical threat.

In summary, the characteristics of the STAI itself and

the research it has generated indicate the appropriateness

of the STAI for the present study.


Physiological Variables

Six physiological variables were measured: the mean

and the standard deviation of forehead EMG, of hand tempera-

ture, and of fingertip skin conductance level. Means and

standard deviations were calculated for each phase of the

experimental session, resulting in six physiological mea-

surements for each of the seven 10-minute phases, or a total

of 42 measures for each subject.


Forehead EMG

Electromyographic (EMG) activity is the electrical

activity that accompanies muscle action. It is detected

by metal electrodes attached to the surface of the skin.

Electromyographic activity is measured in microvolts









or millionths of a volt (Autogen 1700 Manual, 1975). Since

muscular action, also known as muscle tension, is propor-

tional to the degree of electrical discharge stimulating the

muscle, the EMG is a direct physiological index of muscle

contraction or relaxation (Grings & Dawson, 1978). The lower

the microvolt level of EMG activity, the more relaxed the

monitored muscle (Hassett, 1978). The forehead, or frontalis

muscle, was chosen because of evidence of its sensitivity to

generalized muscle tension in the upper part of the body

(Whitehead, 1978). Budzynski (1973) concluded that lessen-

ing of forehead EMG levels contributes to "a general decrease

in arousal level" (1973, p. 541). However, other investigators

have reported opposite conclusions about the generalization

of lowered forehead EMG activity to other muscles (Siddle &

Wood, 1978).

The present study considered other muscle groups, such

as the forearm and neck muscles, for EMG activity measure-

ment. However, movement of arm and throat muscles, necessi-

tated by experimental activities like talking and position

adjustments, interfered with valid measurement of stress-

related and relaxation-related changes in EMG activity. The

Autogen 1700 Feedback Myograph was the instrument used, with-

out the feedback modalities, to measure a subject's forehead

EMG activity (Figure 2).


































Figure 2. Subject with forehead EMG electrodes,
tube, and throat collar in place.


nasogastric


Figure 3. Autogen 1700, 2000b, and 3000 for monitoring
physiological variables.









Hand Temperature

Hand temperature is affected by sympathetic activity

of the autonomic nervous system (Danskin & Walters, 1973).

The temperature of the skin is largely a function of
peripheral circulation. Vasoconstriction, a decrease
in diameter of peripheral arteries caused by sym-
pathetic nervous system (SNS) activation, lowers
skin temperature. Vasodilation, an increase in the
diameter of peripheral arteries caused by SNS relaxa-
tion, raises skin temperature. (Hassett, 1978, p. 65)

Although skin temperature can be affected by climate and

blood viscosity, it was assumed that these variables remained

constant during an experimental session. However, a several

second lag often occurs between vasodilation and temperature

increase at the skin surface (Autogen 2000b Manual, 1975).

The present study measured hand temperature with the

Autogen 2000b Feedback Thermometer, without using its feed-

back modalities (Figure 3). A temperature probe was attached

to the upper surface of the left hand (Figure 4). At the tip

of the probe was a tiny semiconductor embedded in an epoxy

bead. The semiconductor served as a temperature sensor when

the epoxy bead was in contact with the skin surface. A strip

of tape maintained the epoxy bead in position on the sub-

ject's hand.


Skin Conductance

Skin conductance is ". .. linearly related to sweat

secretion" (Hassett, 1978, p. 36). "The unanimity of

studies on the topic of increased sweating to emotionally

charged stimuli is quite compelling" (Hassett, 1978, p. 35).


































Figure 4. Temperature probe taped to hand and skin conduc-
tance sensors attached to fingers.


Figure 5. Autogen 5600 and P-5000 Alphanumeric Printer.









The term "skin conductance level" denotes the absolute value

of electrodermal activity measured in a specific skin area

(Autogen 3000 Manual, 1975). Autonomic nervous system

activation is associated with increased skin conductance;

relaxation is associated with lessened skin conductance. The

Autogen 3000 was used to measure skin conductance level

(Figure 3). The present study measured skin conductance by

means of sensors attached with velcro fasteners to the tips

of the index, middle, and ring fingers of the left hand

(Figure 4).


Data Collection and Recording

The Autogen 5600 minicomputer (Figure 5) collected data

from the EMG, temperature, and skin conductance monitoring

equipment and computed means and standard deviations of

each physiological variable for each phase of the experi-

mental session. The P-5000 Alphanumeric Printer (Figure 5)

provided a printed record tape of these data for each sub-

ject.


Esophageal Variables

Four esophageal variables were measured: frequency and

intensity of swallow-related contractions and frequency and

intensity of spontaneous contractions. Measurements of these

variables occurred at each of four esophageal sites: the

proximal, upper-mid, lower-mid, and distal areas. In this

way, the length of the body of the esophagus was monitored.









The upper esophageal sphincter and the lower esophageal

sphincter were both excluded from study.


Swallow-Related Contractions

Swallow-related contractions are normal sequelae of the

act of swallowing (Benjamin, Gerhardt, & Castell, 1979).

Their frequency is related to the frequency of swallowing.

Their intensity, that is,their peak pressure as measured by

the contraction with the greatest amplitude within a given

time interval, is judged to be within the normal range if it

falls between 75 and 175 mm Hg, as measured by standard

manometry (Benjamin et al., 1979).


Spontaneous Contractions

Spontaneous, or nonswallow-related contractions,gener-

ally occur at a low rate in individuals without esophageal

motor disorders, although their incidence varies from indi-

vidual to individual in the normal population (Nagler &

Spiro, 1961). Spontaneous contractions in the lower two-

thirds of the esophagus seem to occur with greater frequency

and intensity in individuals with esophageal motor disorders,

such as diffuse esophageal spasm, than in normal individuals

(Pope, in Sleisinger & Fordtran, 1978).


Esophageal Measurement

Initial evaluation of esophageal function took place

by means of a procedure called standard manometry. In the

present study, standard manometry entailed the introduction









of a four-lumen, flexible polyvinyl tube (Figure 2, Figure 6)

into the esophagus through the nose or mouth. The distal end

of the tube was initially positioned in the stomach before

being withdrawn in small gradual steps during standard

manometry. Each lumen of the tube had a side orifice for

the purpose of measuring contractile pressures. The lower-

most, or distal, orifice was four centimeters from the dis-

tal tip of the tube. The distal orifice measured pressures in

the distal esophagus when the tube was so positioned. The

other three orifices, located above the distal one, measured

pressures in the lower-mid, upper-mid,and proximal esophagus,

respectively. Each orifice was located approximately four

centimeters from the next one when the tube was in position

within the esophagus. Manometric, or esophageal, measure-

ments were, therefore, obtained over a 16-centimeter length

of esophagus simultaneously. The lumens were mechanically

perfused with water on a continuous basis, in order to mea-

sure esophageal pressures. A contraction squeezed the water

column in a lumen and the amount of pressure exerted by the

contraction was measured. To assess whether a subject's

esophageal functioning was within the normal range, a pro-

cedure called standard manometry was performed during Phase 2

of the experimental session.

During standard manometry, the esophageal, or naso-

gastric, tube was gradually withdrawn from the stomach

through the lower esophageal sphincter into the body of the







































Figure 6. Four-lumen, flexible nasogastric tube (at right)
swallow-recording throat collar (at left).









esophagus, resulting in a gradual rise and fall in pressure

readings. This rise and fall indicated that the pressure

recording units had entered the body of the esophagus

(Earlam, 1975). The units were pulled out at one centimeter

intervals while swallows occurred at least once every 45

seconds. In this way, swallow-related contractions were

measured. If a subject did not swallow for approximately 60

seconds, the technician instructed the subject to swallow so

that a sufficient number of swallow-related contractions was

assured for valid measurement.

A Hewlett-Packard 7758A, eight-channel writer-recorder

(Figure 7) provided tracings on thermographic paper. Similar

to ECG tracings of cardiac activity, these tracings provided

records of esophageal pressure measurements at a rate of one

millimeter per second. The tracing's peaks and valleys

represented the frequency and intensity of esophageal contrac-

tions (Appendix C). Swallow-related contractions were differ-

entiated from spontaneous, or nonswallow-related,contractions

by referring to tracings of the throat's muscular activity.

The throat's muscular activity was measured with a water-

perfused pressure recording tube imbeded in a soft gauze

collar which was attached with velcro strips around a sub-

ject's neck (Figure 2). Spontaneous contractions were

identified where a contraction had occurred without refer-

ence to the act of swallowing, as recorded on Channel 7 of

the thermographic paper. Five channels, or horizontal rows,




















































Figure 7. Hewlett-Packard 7758A eight-channel writer-
recorder.









of tracings appeared on a subject's esophageal record.

Channels 1 through 4 correspond to the four monitored esopha-

geal sites. Channel 1, located at the top of the record

(Appendix C), represents readings from the proximal eso-

phageal area; Channel 2, immediately below Channel 1 on the

record, shows upper-mid area measurements; Channel 3, lower-

mid; and Channel 4, distal. Channels 5 and 6 were left

blank. Channel 7 (Appendix D) displays measurements of

throat movements associated with the act of swallowing.

The writer-recorder lacked the capability of time record-

ing. Therefore to coordinate data recording of esophageal

variables with that of physiological variables, the tech-

nician marked the beginning and the end of each phase during

the experimental session with several vertical black lines

and wrote the phase number beneath that section of the record

for identification purposes.


Procedures

Upon arrival at the Esophageal Studies Laboratory of

the Miami Veterns Administration Medical Center, a subject

was asked to sign an informed consent form (Appendix E),

which indicated voluntary participation in the study. The

subject also signed a financial compensation voucher in the

amount of one hundred dollars for the subject's participation

in the study. The informed consent form presented the study

as an investigation of the possible effects of stress and

of relaxation on esophageal functioning. The stressful









stimulus was described as "timed testing" and the relaxing

stimulus as "music" on the informed consent form. However,

a relaxation instructions tape was substituted for music, and

the subjects were orally informed of that change by the experi-

menter. No further explanation of either the stressful or

of the relaxation stimulus was given except that the stress-

ful stimulus would not be painful. The esophageal technician

and the experimenter walked the subject around the laboratory,

explaining and demonstrating their equipment, with which most

subjects were unfamiliar, except for the nasogastric tube.

Then, the experimenter instructed the subject to sit on the

hospital table and to assume a comfortable supine position.

While the experimenter explained what she was doing, she

scrubbed the subject's forehead with an alcohol wipe to

remove traces of oil, and attached three EMG electrodes, one

above each eyebrow and the third, or ground, in the middle of

the forehead (Figure 2), according to instructions in the EMG

manual (Autogen 1700 Manual, 1975). A temperature probe was

attached with tape to the subject's left hand, on its upper

surface, between the thumb and forefinger. Skin conductance

sensors were attached to the index, middle, and ring fingers

of the subject's left hand. Following these procedures, the

experimenter instructed the subject to lie quietly while

she checked the equipment for proper functioning. The

subject was told that he or she was allowed to speak, and the

esophageal technician talked with the subject for a 10-minute









adaptation interval, during which the experimenter checked

the equipment.


Phase 1 (Baseline)

After checking the equipment, the experimenter informed

the subject that baseline data on EMG, skin temperature, and

skin conductance would be collected, and that the subject

could continue talking during the baseline interval.

At the end of the 10-minute physiological baseline, or

Phase 1, the technician instructed the subject to sit up and

face her. The recording sensors remained in place, and

physiological measurement continued. The technician informed

the subject that she would ease a lubricated tube into one

of the subject's nostrils until it reached the back of the

throat, at which time she would instruct the subject to

begin swallowing, so that the tube could enter the esophagus.

The technician passed the tube into and up the nostril and

once it entered the esophagus, she instructed the subject

to continue swallowing so that peristaltic activity could

move the tube down the esophagus. The technician monitored

its progress and positioned it so that one end of the tube

was in the subject's stomach. The subject was then instruc-

ted to resume a comfortable supine position (Figure 8). The

technician attached a swallow-recording collar around the

subject's neck with velcro straps. Following that sequence

of procedures, a five-minute recovery interval occurred to

allow the subject to adapt to the tube and the collar, while

the technician checked her equipment.















































Figure 8. Subject in supine position with recording equip-
ment.









Phase 2 (Standard Manometry)

Following the recovery interval, the technician per-

formed a standard manometry procedure during Phase 2. Dur-

ing standard manometry, the tube was withdrawn from the

stomach into the esophagus in 1 cm steps, until the Channel 1,

or proximal, recording device had passed through the lower

esophageal sphincter into the distal esophagus. The tube

continued to be moved up the body of the esophagus in 1 cm.

steps, while the subject swallowed at least once each minute.

If a subject failed to swallow for approximately 60 seconds,

the technician asked the subject to swallow. In this way, a

sufficient number of swallow-related contractions were pro-

duced to assure accurate assessment. At the completion of

the standard manometry, or Phase 2, the technician reposi-

tioned the tube so that the proximal recording device,

corresponding to Channel 1 on the esophageal tracing, was

in the proximal esophagus; the upper-mid recording device,

corresponding to Channel 2, was in the upper-mid esophagus;

the lower-mid device, corresponding to Channel 3, was in

the lower-mid esophagus; and the distal device, corresponding

to Channel 4, was in the distal esophagus. The technician

then anchored the tube with adhesive tape strapped to the

cheek and the bridge of the nose (Figure 2). The tube

remained stationary throughout the remainder of the experi-

mental session, and did not interfere with breathing or

talking.









Phase 3 (Recovery from Manometry)

Following Phase 2, subjects were once again informed

that they could talk, if they wished, while more baseline

measurement occurred (Phase 3). Phase 3 provided 10 minutes

of both physiological and esophageal measurement, while the

subject was allowed to recover from the previous procedures.


Phase 4 (Stress or Relaxation)

At the beginning of Phase 4, the experimenter delivered

one of two possible sets of oral instructions to the sub-

ject, depending on whether the subject had been assigned to

the Early Stress order or to the Early Relaxation order. If

the subject had been assigned to the Early Stress order, the

experimenter told the subject that a tape of a quiz would be

played very shortly, and that the subject should speak only

at the times indicated by the taped instructions preceding

the quiz. Taped instructions preceding the quiz told the

subject to answer questions aloud in the allotted time before

the next question began, and that the tape would be stopped

halfway through the quiz, in order to provide feedback about

the subject's performance on the first part of the quiz.

Following the taped instructions and before the quiz began,

the experimenter told the subject that she would write down

the subject's answers to the quiz questions, as the subject

said them aloud. The quiz tape was begun and then stopped

halfway through the quiz, following Question 17. Without re-

gard to the subject's actual quiz performance, the experimenter









informed the subject that he or she had made six errors of

the total of 17 questions on the first part of the quiz,

which placed the subject's performance somewhat below the

norm for medical (premedical) students for that part of the

quiz. The experimenter urged the subject to concentrate in

order to improve his or her performance during the second

part of the quiz. The quiz tape resumed where it had been

stopped, and the remaining quiz questions were heard while

the experimenter continued to write down the subject's

answers. The taped instructions preceding the quiz had in-

formed the subject that the final score would be disclosed

only at the termination of the experimental session. If the

subject inquired or commented about his or her performance

during the experimental session, the experimenter replied

noncommittally that she would disclose the subject's final

score at the end of the session.

If the subject had been assigned to the Early Relaxa-

tion order, the experimenter informed the subject that a

tape of relaxation instructions would be played very shortly,

and that the subject should refrain from speaking while the

tape played, but should follow the instructions heard on the

tape. The tape played for a 14-minute interval, during

which the experimenter and the technician refrained from

speaking and seated themselves out of the subject's range of

vision, to avoid distracting the subject. Physiological and

esophageal measurements were recorded during the final 10









minutes of the relaxation tape. If the subject had been

assigned to the Early Stress order, the same measurements

were recorded during the final 10 minutes of the taped quiz.

In each case, the first 5 minutes were unrecorded to allow

the subject to adapt to the stimulus situation.


Phase 5 (Recovery from Stress or Recovery
from Relaxation)

Following Phase 4, a 10-minute recovery interval, Phase

5, occurred, during which the technician and the experimen-

ter talked with the subject while esophageal and physiological

measurements were recorded automatically. The technician

and the experimenter refrained from discussing the experi-

ment during each of these conversations with the subject.

The subject was encouraged to speak so that the activity

that the subject engaged in during the recovery phases would

be comparable to the activity, i.e. talking, required during

the stress situation of the experimental session.


Phase 6 (Stress or Relaxation)

Phase 6 represented the stress situation for subjects

assigned to the Early Relaxation order and the relaxation

condition for subjects assigned to the Early Stress order.

The stress situation and the relaxation situation were pre-

sented in the same manner as already described in Phase 4.


Phase 7 (Recovery from Stress or Recovery
from Relaxation)

Phase 7, the final 10-minute interval, was another

recovery phase during which esophageal and physiological









measurements were recorded, as before, while the technician

and the experimenter talked with the subject. Following

Phase 7, the equipment was turned off and the recording

sensors and the nasogastric tube were removed from the sub-

ject's body.


Termination of the Experimental Session

After allowing the subject several minutes for re-

covery, the experimenter typically informed the subject that

his or her performance during the second part of the quiz

had been superior to that of the first part, and, therefore,

the overall score was slightly above the norm for comparable

students. In a few cases in which the subject had ceased

answering all or most questions during the second part of the

quiz, the experimenter modified this procedure, and informed

the subject that the quiz had no demonstrable relationship

with medical school performance and that there was no evi-

dence to suggest that performance on the quiz could predict

future success in medical school. The experimenter told the

subject that the study was still in progress, and that it

was important to the study's success that the subject re-

frain from discussing it with colleagues until the study's

completion. The experimenter explained that the subject's

data and those of previous subjects would not be useful

if future subjects knew the details of the experiment.

However, the subject was told that he or she could answer









questions from other students about the nasogastric tube and

the esophageal measurement procedure, a topic about which

students seemed to be curious. All subjects agreed to re-

frain from discussing the study. The experimenter questioned

subjects following the experimental session and found no

evidence that subjects had any prior knowledge of the nature

of the stress or relaxation condition, other than the de-

scription they had read in the informed consent.


Data Compilation and Analysis


Data Compilation

Prior to statistical analysis, the esophageal records

were converted into numerical data. The peak contractions

were computed by measuring the height of every contraction

along the vertical axis, within each 10-minute phase, and

identifying the highest peak for each phase. The frequency

of contractions was computed by counting the number of

contractions along the horizontal axis for each phase. In

this way, the frequency and intensity of contractions for

each of the four esophageal sites, corresponding to Channels

1 through 4 on the esophageal records, were computed

(Appendix F). Swallow-related contractions were differen-

tiated from spontaneous, or nonswallow-related, contractions

by referring to Channel 7,the tracings of throat movements

associated with the act of swallowing. Systematic spot

checks of the counting and recording procedures helped to









assure accuracy. As previously described, means and standard

deviations of each of the physiological variables had been

computed and recorded automatically for each subject for each

phase of the experimental session. Those data and the numeri-

cal esophageal data were transferred to tabulation forms for

ease of data access. The means and standard deviations for

the esophageal and the physiological variables are found in

Appendix G.


Data Analysis

A multiple analysis of variance (MANOVA) was performed

on the esophageal and on the physiological data, yielding

significant results. Therefore, the present study used a

repeated measures analysis of variance (ANOVA) for prelimi-

nary analysis of the esophageal and the physiological data.

The Duncan's multiple range test followed the ANOVA to test

for significant differences between means where the ANOVA had

identified significant main effects or interactions. The

Duncan's test is a multiple comparison procedure for carry-

ing out all pairwise comparisons among means (Kirk, 1968).

The Duncan's procedure is most appropriately used for hypothe-

sis testing. The present study used the Duncan's test uni-

formly for testing all variables, even in the case of one

variable, the frequency of swallow-related contractions,

where no prior hypothesis had been formulated. Since rela-

tively few significant differences were revealed for that

variable, it was decided to forego further testing with a

more conservative procedure than the Duncan's.









Statistical analysis of the esophageal data took place

for each of four variables: frequency of spontaneous con-

tractions, intensity of spontaneous contractions, frequency

of swallow-related contractions, and intensity of swallow-

related contractions. Since important neurological and

myogenic differences affect the various esophageal sites, as

previously discussed, the data for each esophageal variable

were not averaged across esophageal sites. Instead, each

variable was analyzed for each site separately. The esopha-

geal data analysis omitted consideration of the baseline and

standard manometry situations because continuous esophageal

measurement had not occurred during those situations, as

previously noted. The ANOVA tested for differences within

and between groups (HA, LA), between treatment situations

(excluding baseline and standard manometry) within and be-

tween orders (Early Relaxation, Early Stress) and between

esophageal sites proximall, upper-mid, lower-mid, distal)

(Table 2).

Statistical analysis of physiological data took place

for each of six variables: forehead EMG mean, forehead EMG

standard deviation, hand temperature mean, hand temperature

standard deviation, skin conductance mean, and skin conduc-

tance standard deviation. The ANOVA tested for differences

within and between groups, within and between orders, and

between treatment situations (including baseline and stan-

dard manometry) for each variable (Table 5). The analysis













Table 2
Main Effects Tested for in ANOVA for Esophageal Variables


1. Esophageal Site:




2. Group:


3. Order:


4. Treatment:a


Proximal (Px)
Upper-Mid (Um)
Lower-Mid (Lm)
Distal (Dl)

High Anxiety (HA)
Low Anxiety (LA)

Early Relaxation (ER)
Early Stress (ES)

(c) Recovery from Manometry (RM)
(d) Stress (S)
(e) Recovery from Stress (RS)
(f) Relaxation (R)
(g) Recovery from Relaxation (RR)


aThe letters preceding the treatments are for ease
of reference. They do not refer to order of importance
or to the chronological sequencing of the treatments
during an experimental session. For instance, data for
subjects exposed to the Relaxation treatment during Phase
4 of an experimental session were grouped with data for
subjects exposed to the same treatment during Phase 6.





53



of physiological data differed from that for esophageal data

in two ways: the former lacked the esophageal site dimen-

sion and the latter lacked data from the baseline and stan-

dard manometry situations. These differences between the

two data sets necessitated the use of separate statistical

models in the data analysis. A .05 rejection region was

adopted for the ANOVA and for the Duncan's test.

Correlations were computed between physiological and

esophageal variables within each phase. A correlation of

.70 or above was considered significant.















RESULTS


Esophageal Variables

Table 2 shows the categories of main effects for which

the ANOVA of each esophageal variable tested. The ANOVA

also tested for significant interactions between two or

more of the categories listed in Table 2. Table 3 shows

the results of the ANOVA of each esophageal variable.

Table 4 shows the results of the Duncan's tests for the

esophageal variables.


Frequency of Spontaneous Contractions (FrSp)

The ANOVA found no significant main effects, but two

significant two-way interactions: an esophageal site by

treatment interaction and a treatment by group interaction.


Esophageal site by treatment interaction

The Duncan's tests were performed to identify signifi-

cant differences in frequency of spontaneous contractions

during various treatment situations at each esophageal site.

In the proximal esophagus, (f) relaxation was asso-

ciated with significantly fewer spontaneous contractions

than was any other treatment situation.

In the upper-mid esophagus, (d) stress was associated

with significantly fewer spontaneous contractions than
















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tion.

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ciated with significantly fewer spontaneous contractions than

either (e) recovery from stress or (g) recovery from relaxa-

tion.

In the distal esophagus, (d) stress was associated

with significantly fewer spontaneous contractions than (g)

recovery from relaxation.


Treatment by group interaction

The Duncan's tests were performed to identify signifi-

cant differences in frequency of spontaneous contractions

during various treatment situations between the HA and LA

groups.

During (f) relaxation, the HA group had a significantly

greater frequency of spontaneous contractions than the LA

group in the lower-mid and the distal esophageal sites.

During (g) recovery from relaxation, the HA group had a

significantly greater frequency of spontaneous contractions

than the LA group in the upper-mid and the distal esophageal

sites.


Intensity of Spontaneous Contractions (InSp)

The ANOVA resulted in a significant main effect for

treatment, and no significant interactions. The Duncan's

tests found that all of the recovery situations-










(c) recovery from manometry, (e) recovery from stress and

(g) recovery from relaxation-were associated with sig-

nificantly higher intensities of spontaneous contractions

than were (d) stress or (f) relaxation or (b) standard

manometry.


Frequency of Swallow-Related Contractions (FrSw)

The ANOVA resulted in no significant main effects, but

in two significant two-way interactions: an esophageal

site by order interaction and a treatment by group interac-

tion.


Esophageal site by order interaction

The Duncan's tests were performed to identify signifi-

cant differences in frequency of swallow-related contrac-

tions at each esophageal site between subjects in the Early

Relaxation order and those in the Early Stress order.

In the proximal esophagus, subjects in the Early Relaxa-

tion order had significantly more swallow-related contrac-

tions than did subjects in the Early Stress order, across

treatment situations.


Treatment by group interaction

The Duncan's tests were performed to identify signifi-

cant differences in frequency of swallow-related contrac-

tions during treatment situations between the HA and the LA

groups.









During (c) recovery from manometry,(e) recovery from

stress, (f) relaxation and (g) recovery from relaxation, the

LA group had significantly more swallow-related contractions

than the HA groups, at all esophageal sites.


Intensity of Swallow-Related Contractions (InSw)

The ANOVA resulted in a significant main effect for

order, and no significant interactions. The Duncan's tests

showed that subjects in the Early Relaxation order had

significantly higher intensities of swallow-related contrac-

tions than subjects in the Early Stress order across treat-

ment situations at all esophageal sites.


Physiological Variables

Table 5 shows the categories of main effects for which

the ANOVA of each physiological variable tested. The

ANOVA also tested for significant interactions between two

or more of the categories listed in Table 5. Table 6 dis-

plays the results of the ANOVA of each physiological vari-

able. Table 7 displays the results of the Duncan's tests for

the physiological variables.


Mean Forehead EMG (EMGM)

The ANOVA resulted in no significant main effects and

no significant interactions. Therefore, no Duncan's tests

were performed for this variable.













Table 5
Main Effects Tested for in ANOVA
for Physiological Variables


1. Group: High Anxiety (HA)
Low Anxiety (LA)

2. Order: Early Relaxation (ER)
Early Stress (ES)

3. Treatment:a (a) Baseline (B)
(b) Standard Manometry (SM)
(c) Recovery from Manometry (RM)
(d) Stress (S)
(e) Recovery from Stress (RS)
(f) Relaxation (R)
(g) Recovery from Relaxation (RR)


aThe letters preceding the treatments are for ease
of reference. They do not refer to order to importance
or to the chronological sequencing of treatments within
an experimental session. For instance, data for subjects
exposed to Recovery from Stress during Phase 5 of an
experimental session have been grouped with data for
subjects exposed to the same treatment during Phase 7.






63



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Forehead EMG Standard Deviation (EMGSD)

The ANOVA resulted in a significant main effect for

treatment and no significant interactions. The Duncan's

tests found that (f) relaxation was associated with signifi-

cantly less variability for forehead EMG than any other

treatment situation. Moreover, the (a) baseline situation

was associated with significantly less variability for

forehead EMG than either (e) recovery from stress or (g)

recovery from relaxation.


Skin Conductance Level (SCLM)

The ANOVA resulted in a significant main effect for

treatment and no significant interactions. The Duncan's

tests found that a significantly higher mean skin conductance

level was associated with (d) stress than with any other

treatment situation, except (e) recovery from stress.

Furthermore, (e) recovery from stress was associated with

a higher mean skin conductance level than (b) standard

manometry, (c) recovery from manometry, or (f) relaxation.

A significantly lower mean skin conductance level oc-

curred during (a) baseline during any other treatment situa-

tion, except (f) relaxation.

A significantly higher mean skin conductance occurred

during (e) recovery from stress than during (b) standard

manometry, (c) recovery from manometry, (a) baseline or

(f) relaxation.









Skin Conductance Level Standard Deviation (SCLSD)

The ANOVA resulted in no significant main effects, but

in a significant three-way interaction: group by order by

treatment. The Duncan's tests were performed to identify

significant differences in skin conductance level standard

deviation between group by order combinations during each

treatment situation.

During (c) recovery from manometry, (d) stress,and

(g) recovery from relaxation, the HA subjects in the Early

Relaxation order had significantly greater skin conductance

level variability than the LA subjects in the Early Relaxa-

tion order.


Mean Hand Temperature (TEMPM)

The ANOVA found no significant main effects but a sig-

nificant two-way interaction: order by treatment. The

Duncan's tests compared mean hand temperature between treat-

ment situations within the Early Relaxation and within the

Early Stress orders.


Early Relaxation order

A significantly higher mean hand temperature occurred

during the (a) baseline situation than during any other

treatment situation except (g) recovery from relaxation.

During (g) recovery from relaxation, mean hand tempera-

ture was significantly higher than during (b) standard manom-

etry, (c) recovery from manometry, or (e) recovery from

stress.









Early Stress order

A significantly higher mean hand temperature occurred

during the (a) baseline situation than during any other

treatment situation.

A significantly lower mean hand temperature occurred

during (f) relaxation than during (c) recovery from manom-

etry (or (a) baseline).


Hand Temperature Standard Deviation (TEMPSD)

The ANOVA resulted in no significant main effects, but

in a significant three-way interaction: group by order by

treatment. The Duncan's tests were performed to identify

significant differences in hand temperature variability be-

tween group by order combinations during each treatment situa-

tion.

During (e) recovery from stress, the HA subjects had

significantly greater hand temperature variability than the

LA subjects in both the Early Relaxation and the Early Stress

orders.

During (g) recovery from relaxation, the LA subjects

had significantly greater hand temperature variability than

the HA subjects in the Early Stress order.


Correlational Data

Table 8 displays the significant correlations ( .70 or

greater) between esophageal and physiological variables.

Significant correlations were found for some group by order











Table 8
Significant Esophageal-Physiological Correlations
for Group by Order Combinations



Group by Order
Esophageala
Early
Relaxation FrSw InSw FrSp InSp


-.79(R)c
.79(RR)
-.73(R)
-.81(RM)


-.70(R) .79(RR) {- 87(R)
-.84(RR)


-.82(R)
-.88(s)


-.83(RM)
-.79(RM)









-.92(R)


-.77(RR)


HA






U

0o
O
r-
LA o

>1






Early
Stress
HA








LA
0

>1
L


EMGM
EMGSD
SCLM
SCLSD
TEMPM
TEMPSD


EMGM
EMGSD
SCLM
SCLSD
TEMPM
TEMPSD



EMGM
EMGSD
SCLM
SCLSD
TEMPM


EMGM
EMGSD
SCLM
SCLSD
TEMPM
TEMPSD


-.72(RM)
76 (R)
.97(RR)


.72(S)


-.71(S)


.72(RR) -.97(RS)


-.89(S)


{.83(RS) }
.78 (RR)


-.74(R)


.83(R)
.73(R)













Key for Table 8
Esophageal-Physiological Correlations

Note: Significant = .70 or above

aEsophageal Measures:

FrSp = Frequency of Spontaneous Contractions
InSp = Intensity of Spontaneous Contractions
FrSw = Frequency of Swallow-related Contractions
InSw = Intensity of Swallow-related Contractions

bphysiological Measures:

EMGM = Mean Forehead EMG
EMGSD = Forehead EMG Standard Deviation
SCLM = Mean Skin Conductance Level
SCLSD = Skin Conductance Level Standard Deviation
TEMPM = Mean Hand Temperature
TEMPSD = Hand Temperature Standard Deviation

Treatment Situations

RM = Recovery from Manometry
S = Stress
RS = Recovery from Stress
R = Relaxation
RR = Recovery from Relaxation









combinations within one or more treatment situations, but not

across all subjects or across all treatments situations.


HA and LA/ Early Relaxation

Significant negative correlations between the fre-

quency of spontaneous contractions and mean skin conduc-

tance were found during (f) relaxation for both the HA and

the LA groups in the Early Relaxation order.

For HA subjects in the Early Relaxation order, a sig-

nificant negative correlation between the frequency of

swallow-related contractions and mean hand temperature was

found during (f) relaxation.


HA and LA/ Early Stress

For HA subjects in the Early Stress order as in the

Early Relaxation order, a significant negative correlation

between the frequency of swallow-related contractions and

mean hand temperature was found during (f) relaxation.














DISCUSSION


Esophageal Variables

The most striking finding in the present study is that

there were relatively few independent variables which sig-

nificantly affected esophageal functioning. Furthermore,

the significant differences that occurred were seldom in the

predicted direction.


Changes During Stress

It had been predicted that stress, compared with the

other treatment situations, would increase the frequency and

intensity of spontaneous contractions and the intensity of

swallow-related contractions. However, no increase in

intensity of spontaneous contractions occurred during stress,

compared with the other treatment situations, at any of the

four esophageal sites monitored in the present study (Table

4). Moreover, no change in the frequency of spontaneous

contractions occurred at two out of the four esophageal sites

during the stress situation. At the other two sites, the

upper-mid and the distal, recovery from relaxation was asso-

ciated with significantly more spontaneous contractions

than was the stress situation. Finally, no increase in

intensity of swallow-related contractions occurred during









stress, compared with the other treatment situations, at any

of the four esophageal sites.


Changes During Relaxation

As a result of a lack of literature about the effects

of relaxation on esophageal functioning, the present study

did not formulate formal predictions about changes during

relaxation. However, it was tentatively proposed that, if

changes during relaxation occurred, those changes would take

the form of decreases in the frequency and intensity of

spontaneous contractions and in the intensity of swallow-

related contractions. One of these variables, frequency

of spontaneous contractions, showed a change in the expected

direction but only in the proximal esophagus (Table 4). In

the lower-mid esophagus, the frequency of spontaneous con-

tractions during the relaxation situation did not differ

significantly from the frequency during the stress situation

or during recovery from manometry. Therefore, little support

was provided for the expectation that relaxation would be

associated with significantly fewer spontaneous contrac-

tions than any other treatment situation. Table 4 shows

that for another variable, intensity of spontaneous con-

tractions, no significant decreases occurred during relaxa-

tion at any esophageal site. Table 4 further shows that no

decrease in a third variable, intensity of swallow-related

contractions, occurred during the relaxation situation at

any esophageal site. In summary, it appears that










relaxation was associated with few decreases in any of the

expected variables.


Comparison of Changes During Stress and
During Relaxation

The present study had predicted that esophageal func-

tioning during stress would differ significantly from that

during relaxation. Contrary to this expectation, esophageal

functioning during the two situations was remarkably similar

for most esophageal variables at most esophageal sites.

Table 9 compares esophageal variables during stress and

during relaxation. Table 9 shows that no significant differ-

ences in the intensity of swallow-related contractions

occurred during stress compared with relaxation at any esopha-

geal site. For another variable, frequency of spontaneous

contractions, no significant differences during stress com-

pared with relaxation were noted at three out of four sites-

the distal, the lower-mid, and the upper-mid. These three

sites had been expected to show changes during stress.

Based on a body of literature that described the lower two-

thirds of the esophagus in symptomatic individuals to be

more likely than the upper third to show various changes

during stress, it had been expected that these sites might

show an increased frequency of spontaneous contractions

during stress in the present study. However, the present

study found that an increased frequency occurred in the

proximal esophagus, or the upper third, but not in the lower












Table 9
Comparison of Esophageal Variables During Stress
and During Relaxation


Esophageal Site N.S.D. Stress>Relax'n Relax'n>Stress


Proximal





Upper-Mid


Lower-Mid


InSpa

InSwc



FrSp

InSp

InSw


FrSpb

FrSwd


FrSw


none


none


FrSp FrSp
(HA only) (LA only)


InSp

InSw


none


FrSw


Distal


FrSp FrSw
(LA only) (LA only)


FrSp
(HA only)


InSp

FrSw

InSw


InSp = Intensity of spontaneous contractions
FrSp = Frequency of spontaneous contractions
InSw = Intensity of swallow-related contractions
dFrSw = Frequency of swallow-related contractions









two-thirds of the esophagus, contrary to the literature

about individuals with diffuse esophageal spasm (Pope, in

Sleisinger & Fordtran, 1978). For the variable, intensity

of spontaneous contractions, Table 9 shows that no signifi-

cant difference between stress and relaxation was found at

any esophageal site. Therefore, almost no support for the

predicted differences in esophageal variables during stress

compared with relaxation was found.

The present study had advanced no specific prediction

about the variable, frequency of swallow-related contrac-

tions, because of a lack of literature about the effects of

either stress or relaxation on that variable. The present

study's findings revealed some significant differences in

the frequency of swallow-related contractions, depending on

group, order, and site.


Comparisons of Esophageal Sites

Before proceeding further, it is important to consider

evidence that different esophageal sites behave differently.

The present study found significant differences in esophageal

variables at different esophageal sites. As has been noted

in the Introduction to this study, two different nerves pro-

vide esophageal motor innervation. Those nerves are the

spinal accessory nerve for the high cervical portion of the

esophagus and the vagus nerve for most of the rest of the

esophageal musculature (Pope, in Sleisinger & Fordtran, 1978).

The proximal esophageal site that was monitored in the present









study corresponds roughly to the high cervical area, and the

other three sites (upper-mid, lower-mid, and distal) corre-

spond to the area referred to as innervated by the vagus

nerve. Therefore, it is possible that the proximal site

monitored in the present study might be expected to behave

differently from the other three sites. Furthermore, the

lower two-thirds of the esophagus, which would encompass the

upper-mid, lower-mid, and distal sites in the present study,

tends to develop motor disorders more frequently than the

upper third, as previously mentioned (Pope, in Sleisinger &

Fordtran, 1978). Therefore, it is reasonable to expect that

stress would be more likely to be associated with increases

in contractile frequency and intensity at the lower three

esophageal sites than at the proximal site in the present

study. In like manner, it would be reasonable to expect

that, if relaxation resulted in any esophageal changes,

those changes would be more likely to occur at the lower

three sites than at the proximal site.

The present study found only partial confirmation for

these predictions about differences among esophageal sites.

In almost all instances where a significant difference

between esophageal sites occurred, that difference was based

on an interaction between site and group or between site and

order. Even then, there were several instances in which

significant differences between esophageal sites during

stress were contrary to expectations. Specifically, for









the HA group, the stress situation was associated with

significantly fewer spontaneous contractions than was relaxa-

tion in the distal esophagus. There were no significant

differences for this variable during stress and relaxation in

the upper-mid and lower-mid esophagus (Table 9).

Results in the expected direction occurred for the LA

group at only one esophageal site, the lower-mid. In the

lower-mid esophagus, relaxation was associated with signifi-

cantly fewer spontaneous contractions than was stress or

recovery from relaxation, for the LA group. At the other

three sites, no significant differences between stress and

relaxation took place. In summary, relatively few signifi-

cant differences in esophageal functioning during stress and

during relaxation occurred. Thus, the significant differ-

ence that occurred in the expected direction was confined

to one esophageal site, the lower-mid for one group alone,

the LA group.

The variable, frequency of swallow-related contrac-

tions, provided the most evidence of decreases during

relaxation, compared with stress and other treatment situa-

tions. In the proximal, upper-mid and lower-mid, esophagus,

relaxation was associated with significantly fewer swallow-

related contractions. The distal esophagus alone failed to

demonstrate any significant change in frequency during

relaxation. For the stress situation, none of the four

esophageal sites provided evidence of significant change in









the frequency of swallow-related contractions. Interpre-

tation of these findings about the effects of relaxation on

the frequency of swallow-related contractions must be tem-

pered with the knowledge that subjects did not speak during

the relaxation situation and, thus, swallowed less often

during relaxation than during the stress situation or any

other treatment situation. Since the frequency of swallow-

related contractions is a function of the frequency of swal-

lows, the most likely interpretation of the findings about

the low frequency of swallow-related contractions during

relaxation is that the frequency is related to instructions

not to speak, rather than to any possible esophageal effects

of the relaxation situation.


Comparison of HA and LA Groups

It had been predicted that the HA group would be more

likely to show esophageal changes associated with stress

and relaxation than would the LA group. Table 10 compares

the HA and LA groups. These comparisons of the HA and LA

groups reveal significant differences in the expected direc-

tion for one variable, frequency of spontaneous contractions.

No significant differences between the two groups were found

for two other variables-intensity of spontaneous contrac-

tions and intensity of swallow-related contractions.












Comparisons of


Table 10
Esophageal Variables Between the
HA and LA Groups


Esophageal Site N.S.D. HA>LA LA>HA


InSp


none


FrSw (during
stress only)


InSw

FrSp

InSp


none


FrSw (during
stress only)


FrSw (for all
but stress)


FrSw (for all
but stress)


InSw

FrSp


InSp


FrSw (during
stress only)


InSw



InSp


FrSw (during
stress only)

InSw


FrSp (during
relaxation
only)


FrSp (during
relaxation,
recovery from
relaxation &
recovery from
manometry)


FrSw (for all
but stress)


FrSw (for all
but stress)


Proximal


Upper-Mid


Lower-Mid


Distal









For the variable, frequency of spontaneous contrac-

tions, the HA group showed a significantly higher frequency

than the LA group in the distal esophagus during three out

of the five treatment situations: relaxation, recovery from

manometry, and recovery from relaxation. In the lower-mid

esophagus, the HA group also showed a higher frequency than

the LA group, but only during the relaxation situation. No

significant differences between the HA and LA groups occurred

at any other esophageal site.

For the variable, frequency of swallow-related contrac-

tions, the present study had not formulated any specific pre-

dictions about differences between the HA and LA groups.

However, the LA group was found to have significantly more

swallow-related contractions at all four esophageal sites

than the HA group in all treatment situations but stress.

Taken together, these findings about the frequency

of spontaneous contractions and the frequency of swallow-

related contractions indicate some significant differences

between the HA and LA groups, but not entirely in the pre-

dicted direction. For example, the LA group showed a signifi-

cantly lower frequency of spontaneous contractions during

relaxation compared with other situations, whereas the HA

group did not.

One possible interpretation of these comparisons of

the HA and LA groups is that the LA group may have been

characterized by generally lower esophageal reactivity









than the HA group. Contrary to such an interpretation, it

may be argued that the LA group had significantly more

swallow-related contractions than the HA group in all but

one treatment situation. This difference in the frequency

of swallow-related contractions might suggest that the LA

group has a more reactive esophagus than the HA group. As

previously discussed, however, the frequency of swallow-

related contractions, unlike the frequency of spontaneous

contractions, is a function of the frequency of swallowing.

Therefore, the LA group's higher frequency of swallow-

related contractions indicates that LA subjects simply

swallowed more often than HA subjects did in the same treat-

ment situations. An examination of other esophageal vari-

ables reveals no significant difference between the HA and

LA groups in the intensity of swallow-related or of spon-

taneous contractions. Consequently, it seems unlikely that

the LA group had a generally less reactive esophagus than

the HA group. Furthermore, Table 10 shows no significant

difference between the two groups during stress on any of

the esophageal variables. In summary, the relaxation situa-

tion seemed to have a differential effect on the LA and HA

groups by significantly decreasing the frequency of spon-

taneous contractions at one esophageal site for the LA

group, but not for the HA group. The stress situation did

not differentiate between the two groups.









Comparison of Early Relaxation and
Early Stress Orders

The present study did not formulate any hypotheses

about the effect of order, i.e. stress prior to relaxation

or relaxation prior to stress, on esophageal functioning.

As previously indicated, no literature on the subject of the

effects of order of stimuli presentation was found. It is

interesting, therefore, that for two of the esophageal

variables-frequency of spontaneous contractions and inten-

sity of spontaneous contractions-no significant differences

between the Early Relaxation and the Early Stress orders

were found. For a third variable, frequency of swallow-

related contractions, Table 11 shows a significant differ-

ence in favor of the Early Relaxation order in the proximal

esophagus and no significant differences in the rest of the

esophagus. Table 11 also shows that for the variable,

intensity of swallow-related contractions, a consistent

pattern of significant differences in favor of the Early

Relaxation order was found at all four esophageal sites

across all treatment situations. Order was the only main

effect found to be significant in the ANOVA for the variable,

intensity of swallow-related contractions; no significant

interactions were found. These results suggest that the

sequencing of stimuli in esophageal studies may determine

one esophageal response parameter, the intensity of swallow-

related contractions. As will be discussed in more detail

later in this report, order also seemed to have a












Table 11
Comparisons of Esophageal Variables Between the
Early Relaxation and Early Stress Orders


Esophageal Site N.S.D. E.R.a>E.S.b E.S.>E.R.


Proximal





Upper-Mid


Lower-Mid


Distal


FrSpc

InSpe



FrSp

InSp

FrSw



FrSp

InSp

FrSw



FrSp


FrSwd

InSwf



InSw


InSw


none


none


none


InSw


none


InSp

FrSw


E.R.
E.S.
CFrSp
dFrsw
FrSw
eInSp

InSw


Early Relaxation
Early Stress
Frequency of spontaneous contractions
Frequency of swallow-related contractions
Intensity of spontaneous contractions
Intensity of swallow-related contractions











significant effect on mean hand temperature during one

treatment situation, recovery from relaxation. Although

the effect of order on mean hand temperature is not as broad

in scope as the effect of order on intensity of swallow-

related contractions, it provides further evidence for the

possible importance of order as a variable in studies of

esophageal response to stressful stimuli. As a cautionary

note, however, it is necessary to point out that the signifi-

cant difference in intensity of swallow-related contractions

between subjects in the Early Relaxation order compared with

the Early Stress order might have been the result of lack

of comparability between the two sets of subjects that

existed before the study. Although random assignment of sub-

jects to the two orders occurred, it might not have controlled

for the possibility of a significant difference between the

two sets of subjects on the variable, intensity of swallow-

related contractions. Some evidence for such a possibility

can be seen in the significant difference in the intensity

of swallow-related contractions that occurred in all

situations, including recovery from manometry which pre-

ceded either stress or relaxation. Esophageal responses

to order alone would be expected to occur following stress

and relaxation, not preceding their presentation. Thus, the

order of presentation of stress and relaxation may be an

important variable in esophageal research, but pre-existing









differences in intensity of swallow-related contractions

between subjects in the Early Relaxation and the Early

Stress orders may be responsible for the significant differ-

ences in that esophageal variable.


Comparisons of Recovery Situations with Relaxation,
Stress and Standard Manometry

Comparisons of stress and relaxation and comparisons of

HA and LA subjects have revealed relatively few significant

differences on any esophageal variable. However, a compari-

son of treatment situations, other than a comparison solely

of stress and relaxation, reveals unanticipated differences

between the recovery situations, on the one hand, and the

stress, relaxation, and standard manometry situations,on the

other. (Esophageal data recorded during standard manometry

has been excluded thus far in the present report, because of

a lack comparability in the esophageal measurement procedures

used during standard manometry compared with subsequent treat-

ment situations, as previously discussed. However, discussion

of data recorded during standard manometry has been included

here for purposes of discussing the variable, intensity of

spontaneous contractions, during recovery from manometry

and standard manometry.) Specifically, for the variable,

intensity of spontaneous contractions, all the recovery

situations-recovery from manometry, recovery from stress

and recovery from relaxation-were associated with similar









intensities at each esophageal site. The intensities during

the recovery situations were significantly higher than

those during stress, during relaxation, or during standard

manometry at each corresponding site. Furthermore, the

variable, frequency of spontaneous contractions, increased

significantly during recovery from relaxation compared with

relaxation at one site, the lower-mid esophagus. A similar

pattern was noted in the upper-mid esophagus where recovery

from stress was associated with a significantly higher fre-

quency of spontaneous contractions than was the stress situa-

tion.

A possible interpretation of these findings about the

differences between the recovery situations and the other

treatment situations is that there may be a delayed esopha-

geal response to stress, relaxation, and standard manometry.

The apparent delayed response seems to occur in the recovery

situations following stress, relaxation, and standard

manometry. The apparent delayed response takes the form of

significant increases in frequency and intensity of spontane-

ous contractions during the recovery situations. It must be

noted that if a response specific or unique to the relaxa-

tion situation had occurred during the recovery from relaxa-

tion situation, it would be expected that a significantly

lower, not higher, frequency and intensity of spontaneous

contractions would occur during recovery from relaxation

than during relaxation. That did not occur. Thus, a sur-

prising aspect of the apparent delayed response is that the









esophagus did not seem to differentiate between stress,

relaxation, and standard manometry. Instead, the esophagus

responded similarly in frequency and intensity of spontaneous

contractions without respect to the order in which they were

presented or the group to which a subject belonged.

It might be argued that the reason for these similari-

ties in esophageal response immediately following stress and

relaxation is that the stress situation and the relaxation

situation did not differ sufficiently from each other to

affect esophageal functioning differentially. This line of

argument would describe the stress situation as not suffici-

ently stressful and the relaxation situation as not suffi-

ciently relaxing. If this were the case in the present

study, then it would be expected that the esophagus had

responded similarly to the two situations as a result of

insufficient differences between the two.

However, analysis of several physiological variables,

to be discussed in more detail later in this study, indi-

cates that stress and relaxation had significantly differ-

ent effects in the expected direction on mean skin conduc-

tance level and on EMG variability. Furthermore, the stress

situation in the present study had been used in a previous

study (Schiffer et al., 1976), which found that the adminis-

tration of an intellectual achievement test was associated

with heart rate changes consistent with stress. The choice

of an intellectual achievement test as a stress situation




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