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An Experimental Study Of Intelligibility Thresholds Of Hypacusic Adults Using Forced-Choice And Yes-No Techniques

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An Experimental Study Of Intelligibility Thresholds Of Hypacusic Adults Using Forced-Choice And Yes-No Techniques

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Content This dissertation has been 64-5164
m icrofilm ed exactly as received
SMITH, B ettye Wilton, 1929-
AN EXPERIMENTAL. STUDY OF INTELLIGIBILITY
THRESHOLDS OF HYPACUSIC ADULTS USING
FORCED^CHOICE AND YES-NO TECHNIQUES.
U niversity of Southern California, Ph. D ., 1963
Speech- Theater
University Microfilms, Inc., Ann Arbor, Michigan
AN EXPERIMENTAL STUDY OF INTELLIGIBILITY THRESHOLDS
OF HYPACUSIC ADULTS USING FORCED-CHOICE
#
AND YES-NO TECHNIQUES
by
Bettye Wilton Smith
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(Speech)
* August 1963
U N IV ER SITY O F S O U T H E R N C A L IF O R N IA
G RA D U A TE SC H O O L
U N IV E R SIT Y PA R K
L O S A N O C L SS T . C A L IFO R N IA
This dissertation, written by
........................B e tty e . W U to n ..S m .ith ..........................
under the direction of hfiX....Dissertation C om
mittee, and approved by all its members, has
been presented to and accepted by the Graduate
School, in partial fulfillm ent of requirements
for the degree of
D O C T O R O F P H I L O S O P H Y
Date - S.U . . 1. 9. 6. 3
ON M ITTEE DISI
TABLE OF CONTENTS
Page
LIST OF TABLES............................ iv
Chapter
I. THE PROBLEM . . .............................. 1
Statement of the Problem
Experimental Hypotheses
Significance of the Problem
Definitions of Terms
Organization of the Remainder
of the Study
II. REVIEW OF THE LITERATURE................... 9
III. SUBJECTS, MATERIALS, PROCEDURES ....... 34
Subjects
Materials
Procedure
IV. PRESENTATION AND INTERPRETATION
OF THE DATA................................ 46
Statistical Procedure
Analysis of the Data
Interpretation
V. SUMMARY, CONCLUSIONS, IMPLICATIONS........ 68
Summary
Conclus ions
Implications
APPENDIXES
Appendix A: Experimenter's Materials ............. 75
Appendix B: Taped Material ........................ 79
Appendix C: Subject Materials
Page
84
Appendix D: Instructions for:
a) Bekesy Audiometry
b) Speech Intelligibility
Threshold Measurements
c) Forced-Choice Threshold
Measurements
d) Speech Detection Threshold
Measurement...................... 91
Appendix E: Subject Data.................... ' 95
BIBLIOGRAPHY...................................... . 97
I
iii
LIST OF TABLES
Table Page
1. Distribution of Bekesy Tracings According
to Etiology of Hearing L o s s ............... 36
2. Counter-Balance Design for the Study......... 41
3. Analysis of Variance Among Means............. 48
4. Results of the £ Test for Related Measures
of Speech Intelligibility Thresholds
Using the Two Indicators................... 50
5. Results of the £ Test for Related Measures
of the SDT and FCT#1 and SDT and FCT#2 . . . 52
6. Results of the £ Test for Related Measures
of the FCT#1 and FCT#2...................... 52
7. Results of the Pearson Product-Moment
Correlation Coefficients and the £
Test of Differences Between r1s for
the FCT#1 and SIT . ...................... 56
8. Results of the Pearson Product-Moment.
Correlation Coefficients for the
FCT#2 and S I T .............................. 56
9'. Results of the £ Test for Related Measures
and Pearson Product-Moment Correlation
Coefficients for the FCT#1 and S D T ........ 58
10. Results of the Pearson Product-Moment
Correlation Coefficients for the
SDT and F C T # 2 .............................. 60
11. Results of the Pearson Product-Moment
Correlation Coefficients for the SDT and
S I T ......................................... 60
...........'____________________i v ______________________..________________ . . . . . .
Table Page
12. Results of the Pearson Product-Moment
Correlation Coefficients for the
FCT#1 and F C T # 2 ................................63
CHAPTER I
THE PROBLEM
In measuring t-he degree of hearing loss in hard of
hearing persons the most common clinical technique has been
the Yes-No technique. The essence of this procedure is that
the clinician presents sounds at various levels of loudness
and pitch (by means of an audiometer) to a patient, and the .
patient is asked to respond When he thinks he has heard
something. Two main .types of test-and—response have been
used: (1) the stimuli are pure tones, and the response is
a signal (such as raising a finger) to indicate when the
patient thinks he detects a sound; (2) the stimuli are
words, and the response is oral repetition of words to indi
cate when the patient thinks that the stimulus is intellig-
i
ible. In both of these variations the patient has the op
tion of responding or not responding to the given stimulus.
When patients are permitted the option described
above, some undesirable variables are likely to interfere
with the objectivity of the testing, e.g., some patients
may be more (or less) cautious than other patients. Because
. 1 .
2
of these undesirable variables, roost clinical measurements
of hearing have been interpreted as approximations with a
margin of error of plus or minus six decibels.^- Therefore
in recent years researchers have sought to develop improved
techniques which would reduce the effects of extraneous var
iables and hence reduce £he limits of clinical error. One
new approach which has not yet been thoroughly explored is
called the forced-choice technique. The essence of this
technique is that the patient, instead of having an option,
is forced to designate the stimulus by choosing (or guess
ing) it from a list.2
Statement of the Problem
The purpose of this experiment was to investigate
whether differences exist between two methods of obtaining
speech intelligibility thresholds on hard of hearing sub
jects, namely the Yes-No technique and the forced-choice
1Raymond Carhart, Audiolocrv. Veterans Administra
tion Department of Medicine and Surgery Information Bulle
tin, IB 10-115 (Veterans Administration, Washington, D. C.,
March, 1960), p. 10.
2Israel Goldiaroond, "Indicators of Perception: I.
Subliminal Perception, Subception, Unconscious Perception?
An Analysis in Terms of Psychophysical Indicator Methodolo
gy, " Psychological Bulletin. LV (November, 1958), 377.
3
technique.
Riflpferimental Hypotheses
The following four hypotheses were tested in the
study:
Hypothesis I: There will be no significant differ
ences between speech intelligibility thresholds obtained on
the same hard of hearing individual using the two types of
indicators of perception: Forced-Choice and Yes-No.
Hypothesis II: There will be no significant differ-:
ences between the speech detection threshold obtained on thej
same hard of hearing individual using the Yes-No indicator
and the speech intelligibility threshold using the forced-
choice indicator.
Hypothesis III: There will be no significant dif
ferences between the two session-to-session thresholds ob
tained on the same hard of hearing individual using the
forced-choice indicator.
Hypothesis IV: There will be no significant differ
ences between the two organic groups, conductive and sen**
sori-neural, in the use of any of the speech tests.
Significance of the Problem
The need to establish consistent and valid hearing
thresholds is important for proper medical interpretation
of a hearing disability. The examining otologist refers to
the audiological evaluation when diagnosing and describing
the severity of the hearing loss and the prognosis regard
ing surgery and the need for rehabilitation. The value of
i
an accurate and consistent audiological work-up is also rec
ognized by the courts of law whose decision it is to estab
lish responsibility for a hearing disability incurred on-
the-job. If it is ruled that the employer or company is
responsible for the disability then the amount of the mone
tary award to be paid to the employee must be decided by
the courts. The armed services and Veterans Administration
were pioneers in this area of medico—legal audiology and
established clinical tools for determining organic hearing
acuity and a schedule for compensating personnel who have
incurred a disability while serving in the armed forces.
The assignment of rating for a hearing loss is based upon
the organic hearing loss revealed by the pure tone thresh
olds and speech audiometry. The need for consistent and
reliable hearing thresholds is unquestionable.
Experimental research has shown that substantial
differences in psychophysical thresholds are dependent upon
the type of indicator of perception used. Clinical audio-
5
1
metry uses the yes-no indicator of perception in obtaining
thresholds of speech intelligibility. The psychophysical
method on which this threshold test was patterned was the
method of constant stimuli.3 It has been observed in clin
ical practice that there are, in some cases, considerable
fluctuations of thresholds during test re—test procedures
which are not confirmed by the etiology of medical diagno
sis. It has been hypothesized that factors other than path
ology account for these fluctuations, such as caution on the
part of the subject to respond at threshold, familiarity
with the vocabulary, attention and emotional influences. It
has also been hypothesized that the method of obtaining
thresholds is influential in causing or permitting fluctua
tions.
Go1diamond, in his review of indicators of percep
tion, reported the results of various experiments which sug
gested that the yes-no indicator tended to admit variance
extraneous to sensory discrimination. This caused decreased!
|
session-to-session reliability, and decreased intra-session ;
reliability. The forced-choice indicator* was not so subject!
3Ira J. Hirsh, The Measurement of Hearing (New
York: McGraw-Hill Book Company, Inc., 1952), p. 100.
6
to these extraneous variables.4
Iekes investigated a clinical application of a
forced-choice technique in pure tone audiometry.^ A group
of normal hearing subjects was tested with pure tones using
both a yes-no indicator and a forced-choice indicator to
establish thresholds for pure tones. He found that the
forced-choice indicator was a better measure of sensory
functioning than the yes-no indicator and the use of the
forced-choice indicator yielded lower pure tone thresholds.
A pilot study using the forced-choice indicator for
establishing speech intelligibility thresholds on normal
£
hearing subjects by Smith resulted in lower thresholds us
ing the forced-choice method. It was concluded that before
complete acceptance or rejection of the use of this type of
indicator for speech audiometry, further study was indicated
using subjects with conductive and sensori-neural hearing
4Goldiamond. loc. cit.. pp. 380-386.
5William K. Ickes, "An Accuracy Indicator for Test
ing Hearing," Journal of Speech and Hearing Disorders, XXVII
(May, 1962), 144-149.
^Bettye W. Smith, "An Experimental Study to Deter
mine Speech Intelligibility Thresholds Using Forced-Choice
Technique" (unpublished research paper. University of South
ern California, 1961), pp. 1-11.
losses.
Utilization of a psychophysical method which elimin^
ates variables extraneous to sensory discrimination by per
mitting greater consistency and reliability would be of con
siderable value in audiological threshold measurements.
Definitions of Terms
Yes-No Indicator {Semantic Indicator).— This is a
measure of auditory stimulus magnitude as indicated by the
subject in terms of Yes or No, with the response itself be
coming the indicator of the presence or absence of the
stimulus.^
Forced-Choice Indicator (Accuracy Indicator).— This
forces the subject to indicate stimulus discrimination by
identifying it in some manner. It is the accuracy of the
response which is the measure of perception, not the re-
Q
sponse itself.
Speech Detection Threshold f SDT).— The sensation
level at which the subject reports he hears but does not
^Ickes, loc. cit.. p. 144.
8Ibid.
8
apprehend the verbal stimulus fifty per cent of the time.
Speech Intelligibility Threshold (SIT).— The sensa
tion level at which fifty per cent of the spondee words are
repeated correctly by the subject with definite prior know
ledge of test vocabulary.
Forced-Choice Threshold (FCT).— The sensation level
at which better than chance guessing is obtained using the
probability scale for predicting better than chance guess
ing.
Organization of the Remainder
of the Study
Chapter II will review the literature in the areas
of psychophysical methods and speech audiometry.
Chapter III will describe the subjects, materials,
equipment and procedures used in the study.
Chapter IV will present the data and interpret the
results of these data.
Chapter V will summarize the study and discuss the
conclusions and implications for future research.
CHAPTER II
REVIEW OF THE LITERATURE
The field of audiology has adapted its testing tech
niques from psychophysical methods. As Hirsh points out,
the method for establishing thresholds for hearing follows
the technique used in the psychophysical method of limits.*"
The audiologist, when establishing hearing thresholds for
pure tones, controls the intensity of the stimuli with the
approach from above and below the thresholds accomplished
at a fixed rate within fixed limits. The subject is in
structed to raise his finger whenever he hears the tone and
lower it when he no longer hears it. The audiologist then
manipulates the introduction of the stimulus.
The generally accepted method for establishing pure
tone thresholds is the one outline
— - ■ ■ — — ...........................................................— ■ - r - - - - - - - ■ ■ ■ - j
^■Hirsh, op. cit.. p. 13.
2H. Hughson and H. Westlake, "Manual for Program
Outline for Rehabilitation of Aural Casualties both Military!
and Civilian, " Transactions American Academy of Qpthalmolocrv
and Oto-Laryngology Supplement, XLVIII (1944), 1-15.
Hughson and Westlake'
9
10
with the modifications recommended by Carhart and Jerger.3
This technique requires the examiner to increase the inten
sity of the pure tone until a response occurs, then decrease
the level of the next stimulus 10 to 15 db and begin another
ascent in five db steps. The threshold is established at
that sensation level where the subject responds to the stim
ulus three' times at the same intensity. The stimulus should
be interrupted rather than continuous as sustained tones in
duce variability in the intensity levels at which responses
occur because of the on-effect followed by a reduction in
sensitivity.4 The use of interrupted stimuli also elimin
ates the possibility of attenuator noise which may be de
tected by the subject and confound the responses to test
stimuli.
A second psychophysical technique adapted for use in
hearing threshold measurement is the method of adjustment.
This technique requires the patient to manipulate the inten
sity of the stimuli rather than having the audiologist con
3Raymond Carhart and James F. Jerger, "Preferred
Method for Clinical Determination of Pure-Tone Thresholds,"
Journal of Speech and Hearing Disorders. XXIV (November,
1959), 330-345.
4Ibid.
11
trol it stipulated by the method of limits.^ The patient is;
instructed to adjust the intensity of the tone so that it isi
just audible. The technique has become more frequently
utilized with the use of the Bekesy audiometer, which was
designed to enable the subjects to plot their own thresholds
6 7 8
for both continuous and interrupted pure tone stimuli. '
The instructions for this test are that the patient press
the attenuator lever as long as he hears the tone and re
lease it when the tone is no longer audible.
The use of this audiometer has become extremely valH
uable in diagnostic audiology as a result of Jerger's study.!
He compared the tracing of interrupted and continuous tones
using the Bekesy audiometer on 434 subjects with various
types of otological diagnoses, by testing the interrupted
signal first and then the continuous tone second. Jerger
_ _ _ — . — --
5Hirsh, op. cit.. pp. 97-98.
6Lennart J. Kopra, "Threshold Recoveries for Contin
uous and Interrupted Pure Tones Following Auditory Fatigue,"
Journal of the Acoustical Society of America. XXVII (Janu
ary, 1955), 201.
^Rauno Palva, "Self-Recording Threshold Audiometry
and Recruitment," Archives of Otolaryngology. LXV (June,
1957), 591-602.
^James JergerBekesy Audiometry in Analysis of
Auditory Disorders," Journal of Speech and Hearing Research.
Ill (September, 1960), 275-287.
12
found that most tracings could he placed into one of four
categories, determined by the relationship between the trac
ings of the interrupted and continuous stimuli, and classi
fied as Type I, XI, III and IV. He concluded that lesions
of the middle ear were characterized by one relationship
(Type I), lesions of the cochlea by a second (Type II), and
lesions of the eighth nerve by a third and fourth (Type III,
IV).9
The third psychophysical technique adapted for clin
ical audiometry is the method of constant stimuli. This
technique requires the subject to indicate whether a given
stimulus is "greater" or "less" for several temporally con
stant stimulus differences.10 This method, according to
Hirsh, constitutes the model for most speech tests used in
speech audiometry.
The experimental procedure is essentially the
psychophysical method of constant stimuli modified in
two ways: (1) a number of speech items to be presented
at any one level may be presented as a group; (2) the
individual stimuli in any group are not necessarily
identical but usually represent speech items that are
thought to be roughly equivalent with respect to intel
ligibility . ^
9Ibid.
^Hirsh, op. cit.. p. 13.
1:LIbid. . p. 133.
13
Speech audiometry has been utilized as a clinical
tool for assessing auditory acuity since the 1940's. Al
though the pure tone audiogram depicted the pattern and de
gree of hearing loss, only pi..diction on the part of the
examiner was possible concerning the reception, perception
and intelligibility of speech. To actually evaluate the
extent of the loss of acuity for speech, the need for devel
oping controlled speech material was recognized.
In 1947 Hudgins et al. described the aims for their
program of audiometric test development at the Psycho-Acous-*
tic Laboratory, Harvard University. Two of their aims were |
to explore the problems involved in the construction of
audiometric tests for directly measuring the hearing loss
for speech and to produce a test suitable for precise meas
urements of all degrees of hearing loss. Their study deter
mined the essential characteristics of the test material and
included the need for the selection of familiar words with
phonetic dissimilarity. They found that the inclusion of
words that differed only with respect to a single sound,
such as plowbov and cowboy -required a finer discrimination
but did not increase the effectiveness of the test as a
measurement of hearing threshold; nor was it necessary to
have a complete representation of English sounds in thresh
14
old measurement. It was, however, important to have these
lists made up of homogeneous words. This homogeneity was
important for two reasons. It increased the probability
that the articulation-gain function using these words would
rise steeply from zero to 100 per cent within a narrow range
t
and it permitted them to determine the threshold of hearing
for speech with the use of as small a number of words as
possible.
Their experiments showed that dissyllabic words
yielded uniformly higher audibility than the monosyllabic
words. The spondee showed the highest audibility as both
*
syllables were equally stressed when compared to other dis
syllabic words such as the trochee or iamb. The curve for
the selected spondees had an average slope of 10 per cent
per decibel over the range between 20 and 80 per cent. The
curve for monosyllables, on the other hand, had a slope of
only four per cent over the same range with the curve for
12
unselected dissyllables falling in between.
Recordings of the spondee word lists were produced
commercially and became the tools for establishing thresh-
12c. V. Hudgins et_al., "The Development of Record
ed Auditory Tests for Measuring Hearing Loss for Speech,"
- The Laryngoscope. LVII (January, 1947), 57-89.
15
olds of hearing for speech. The Harvard Psycho-Acoustic
Auditory Test No. 9 and No. 14 selected for use in the pres
ent study provided the vocabulary of eighty-four spondee
words.
Of the two, Auditory Test No. 14 was more commonly
employed; probably because it enabled a more direct approach
to measurements. This record is made up of seventy words
which were carefully recorded at the same level with three
seconds between words. The intensity at which they are in
troduced to the subject is controlled by the audiologist,
who makes all adjustments with the attenuator of the speech |
audiometer. The sensation level at which the patient re
sponds to fifty per cent of the words is taken as the speech
reception threshold.
Auditory Test No. 9 was originally designed for
written responses and Auditory Test No. 14 was developed
13
for oral production by the patient.
The use of the spondee words and the recommended
technique described above has been the general practice in
speech threshold measurement since the works by Egan and
^Raymond Carhart, "Instruments and Materials for
Speech Audiometry," Acta Oto-Larvnqoloaica. XL (Fasc. V-VI,
1951), 321.
16
Hudgins et al. were published. In 1952 the Central Insti
tute for the Deaf completed a study resulting in Auditory
Test Nos. W-l and W-2 for use in speech threshold measure
ment. These tests are made up of thirty-six spondee words
which were adapted from the Hudgins et al. lists and were
t
intended to supplant the Auditory Test No. 9 and No. 14.
They are the result of a study completed by Hirsh, et al.
in an attempt to satisfy needs that were not fulfilled by
the older tests. One of the basic improvements which was
made was that the vocabulary for the spondee lists was re
stricted so as to include only those words that met certain
criteria of familiarity. Those words which were judged the
most and least familiar were eliminated. The completed
lists were recorded with the carrier phrase "Say the word .
. .” at a level 10 db above the spondee word. According to
Hirsh, the vocabulary and the method of recording resulted
14
in homogeneous intelligibility.
The development of standardized material and equip
ment for speech audiometry tests was a major advance in the
field of audiology for it provided means whereby the patient
14Ira Hirsh et al., "Development of Materials for
Speech Audiometry," Journal of Speech and Hearing Disorders.
XVII (September, 1952), 321-337.-
17
could indicate his level of speech reception. Thresholds
obtained on the hard of hearing patient compared to the
thresholds of normal hearing subjects indicate the degree
of loss in hearing acuity or in other words how much more
intense the speech signal had to be for the hard of hearing
subject to perceive it compared to the normal hearing.
A second report was published by Egan concerning
the research conducted at the Psycho-Acoustic Laboratory.
He reported the results of this research which investigated,
among other things, the procedures that were found to be
particularly useful in the measurement of the intelligibil- I
ity of speech and the requisites of speech test material.
The spondaic word lists were found to have homogeneous audi
bility as each individual word was as difficult as each
other word.
Thresholds of detectability were defined as the sen
sation level at which the subject was just able to detect
the presence of speech sounds fifty per cent of the time.
He found that 8 db above the speech detection threshold the
listeners were able to understand continuous discourse but
with some difficulty. They defined this measurement as the
•threshold of perceptibility.
Egan found that the threshold of intelligibility
18
was about 4 db above the threshold of perceptibility. These
findings indicated that the threshold of intelligibility was
approximately 12 db above the threshold of detectability for
normal hearing subjects. During all of these described
threshold measurements connected discourse was used as the'
speech stimuli.^
The term speech intelligibility threshold or speech
reception threshold (SRT) became synonymous with reference
to hearing thresholds for speech.
The techniques for establishing the threshold of
intelligibility (Speech Reception Threshold) have remained
basically unchanged since their introduction and standardi
zation by Hudgins and Egan. Clinical practice has found i€
reliable in the majority of cases. There are instances
however when, due perhaps to subject bias, inadequate in
struction or lack of motivation, thresholds are not easily
obtained. This is frequently observed in medico-legal audi-
ology. The fluctuations that occur during test-retest and
session-to-session testing are not supported by the etiology
or medical diagnosis.
Many studies have been completed in the area of
l^Jajnes Egan, "Articulation Testing Methods,"
The Laryngoscope. LVIII (September, 1948), 955-991.
19
so-called non-organic hearing loss.^*' ^9 These stud
ies include ways to detect the presence of non-organic hear-<
ing loss using various techniques and tests. One of the
first, utilizing speech audiometry, was the Doerfler-Stewart
developed in 1946 using speech-to-noise ratio as the under
lying theory. This test examines the subject's ability to
respond to spondee words in the presence of a saw tooth type!
masking noise. The theory of the test is that when some de
gree of non-organic hearing loss is present, the masking
noise will interfere with his ability to judge the point at
which he should no longer be able to respond to the test !
\ i
material. Doerfler and Stewart reported the criteria for
20
evaluating the results of this test. These criteria,
■^Leo Doerfler and Kenneth Stewart, "Malingering and.
Psychogenic Deafness," Journal of Speech and Hearing Disor
ders . XI (September, 1946), 181-186.
w- Gibbons and R. A. Winchester, "A Delayed
Side-tone Test for Detecting Uniaural Functional Deafness,"
Archives of Otolarvngology. LXVI (January, 1957), 70-78.
-*-®Howard B. Ruhm and Raymond Carhart, "Objective
Speech Audiometry: A New Method Based on Electrodermal Re
sponse," Journal of Speech and Hearing Research. I (June,
1958), 169-178.
■ * - 9Howard B. Ruhm and Otto J. Menzel, "Objective
Speech Audiometry in Cases of Non-organic Hearing Loss," Ar
chives of Otolaryngology, LXIX (February, 1959), 212-219.
Doerfler and Stewart, loc. cit.. pp. 181-186.
20
"however, do not necessarily predict the organic threshold
but only indicate Whether caution should be observed during
the audiological evaluation of a patient.
The use of Electrodermal Response (EDR) in estab
lishing reliable and valid thresholds for pure tones encour
aged researchers to evaluate this tool as a means of obtain
ing objective speech reception thresholds. Ruhm and Carhart
reported the results of their study in setting up a proced
ure for obtaining objective speech reception thresholds and
the validity of these thresholds. The reported procedure
was to select one spondee word as the key item. The word
was presented at an audible intensity and was always fol
lowed by an electric shock, which was omitted whenever any
other non-key-item spondee was presented. This constituted
the conditioning procedure which maintained the theory that
the key word only would elicit EDR and all other words would
remain neutral.
After conditioning, the stimulus level was varied
until the minimum intensity level at which the key word
elicited Electro-reception-response was found. This level
was determined by them to be the threshold of intelligibil
ity. This was based on their observations that both neutral
stimuli and the key word elicit EDR if they are presented
21
just under this level with all responses equal but of a
lesser magnitude than the supra-threshold response to the
key word. Ruhm and Car hart interpreted these reduced EDRs
to all speech stimuli as indicating that the subject detect
ed the presence of speech but could not differentiate wheth
er or not the item was the key word.
Although they point out that this method requires
sufficient language skill and maturity on the part of the
subjects to be able to achieve perceptual differentiation
among speech stimuli, it is a method recommended by them to
delineate the speech thresholds of adults exhibiting non-
organic hearing losses.21
Ruhm and Menzel subsequently reported the applica
tion of the key test word technique, described above, on
cases with non-organic hearing loss to appraise the useful
ness of the method.
The reported results indicated substantially better
thresholds as measured by electrodermal speech audiometry
than conventional methods. It was proposed that the objec
tively measured threshold was a close approximation of the
organic speech reception threshold. A side effect observed
21Ruhm and Carhart, loc. cit.
22
was that voluntary SRT obtained after ESRT were, with few
22
exceptions, better than those obtained before.
In cases involving medico-legal audiology, it would
be difficult to defend the validity of the responses to just
t
one word as required in the Ruhm and Carhart study; particu
larly, when the patient does not repeat the word back to the
examiner as perceived.
Chaiklin's study, in 1959, assessed the relative
hearing level at which the subjects produced EDR's to a
speech stimulus. Chaiklin established thresholds of per
ceptibility for running speech, Speech Detection Thresholds
and Speech Reception Thresholds, using CID W-l spondaic
words. The phrase "Now you hear me;*1 was the speech stimu
lus for electrodermal responses and conditioning. The
hearing acuity of the subjects fell within normal limits.
His results were as follows: (1) mean SRT W-l was 9 db
higher than mean SDT; (2) the mean threshold for percepti
bility for running speech was 3.46 db higher than mean SRT
W-l and the mean EDR speech threshold was 2.64 db lower
than SRT W-l (voluntary) with mean EDR 6.36 db higher than
SDT. The majority of subjects had EDR thresholds within
22Ruhm and Menzel, loc. cit.
23
-5 db of SRT W-l; however, some subjects produced acceptable;
EDRs at levels where the conditioned stimulus was not intel
ligible to them. Chaiklin points out that the effects of
this generalization would have to be recognized in any clin-
23
ical application of this procedure.
The use of these techniques in establishing speech
intelligibility thresholds raises certain objections.
Chaiklin stated that some subjects produced acceptable EDRs
at levels where the conditioned stimulus was not intelligi
ble to them. This can lead, in the case of unskilled or
biased clinicians, to certifying or recording thresholds
that are false. One of the prime criticisms in using condi-t
tioned EDRs as indicative of speech intelligibility thresh
olds is the inability to be confident of testing what is
intended to be tested. In the case of objective EDR speech
audiometry it can .be assumed only that the subject responds
in a different manner to the test stimuli, but not that this
is the threshold of intelligibility.
There are certain problems inherent in the adminis
tration of this threshold technique such as testing time
22Joseph B. Chaiklin, "The Conditioned GSR Auditory
Speech Threshpld," Journal of Speech and Hearing Research.
II (September, 1959), 229-243.
24
required, extinction to conditioning, and the inability of
subjects to meet the conditioning criteria.
Audiology is continually looking for new and im
proved techniques for more efficient methods of establishing
1
thresholds for speech. The tests described above tend to
eliminate the possibility of patient bias. However, the
time involved and probably lack of validity suggests the
need for further research in this area.
One psychophysical method for establishing thresh
olds which has only recently been applied to hearing meas
urement is the forced-choice technique. When discussing the
procedures for establishing thresholds of hearing it was
pointed out that the subject indicates by raising his finger
when he hears a tone and lowers it when he no longer hears
the tone; or, in the case of speech reception thresholds,
the subject repeats aloud the words which he hears. These
types of responses are classified as the semantic indicators
or the yes-no indicator. In recording the responses using
these indicators, the examiner takes the subject’s report
at face value. If for some reason the subject is anxious to
show how sensitive his hearing is, he may give many false
positive responses and an unsophisticated examiner may ob
tain spuriously low thresholds which are not indicative of
25
the perception or detection of stimuli. On the other hand,
the subject for certain reasons may fail to report a stimu
lus that was really perceived thereby giving a number of
24,
false negative responses.
Blackwell, using both auditory and visual stimuli,
compared the semantic and the accuracy indicators, using the;
yes-no response as the semantic indicator and forced-choice
response as an accuracy indicator. He found that the yes-
no indicator was influenced by variables extraneous to sen
sory discrimination and concluded that if these were per
ceptual error variance, this indicator, according to test
theory, should exhibit less session-to-session reliability
and less intra-session reliability than the forced-choice
indicator. He further theorized that if the yes-no indica
tor included extraneous variance, it should yield higher
25
thresholds than the forced-choice indicator. Blackwell
confirmed these beliefs in experimental research, concluding
24Israel Goldiamond, "The Relationship of Subliminal
Perception to Forced-Choice and Psychophysical Judgments,
Simultaneously Obtained," American Psychology. IX (August,
1954), 378. (Abstract.)
25H. R. Blackwell, "The Influence of Data Collecting
Procedures upon Psychophysical Meas.urement of Two Sensory
Functions,” Journal of Experimental Psychology. XLIV (Hovem-*
ber, 1952), 306-315.
26
that "forced-choice thresholds were significantly smaller
than corresponding thresholds obtained with the yes-no indi-
26
cator." The yes-no indicator had less apparent validity
than forced-choice.
Forced-choice technique was first developed by Paul
Horst with reference specifically to personality scales.27
It was later applied by Wheery to the problem of rating Army
28
officers. Travers reported defects in the rationale in
the use of this technique as used in the Officer Efficiency
Report because the rater had to make judgments which were
illogical. Upon examining the validation studies of forced-
choice assessment methods he found that the evidence did not
support some of the claims made for the validity of the
technique.
Baier, in his reply to Travers' article, refuted
Travers' statements by pointing out that the forced-choice
technique had been used in personality inventories and self-
26H. R. Blackwell, "Psychophysical Thresholds: Ex
perimental Studies of Methods of Measurement," Engineerinq
Research Institute Bulletin No. 36 (1953), p. 199.
27R. M. W. Travers, "A Critical Review of the Valid
ity and Rationale of the Forced-Choice Technique," Psycho
logical Bulletin. XLVIII (January, 1951), 62.
2®Ibid.
27
description forms where its usefulness was evident. Even
higher validities were obtained with modifications of con
ventional forced-choice technique based on suppressor
29
theory.
Allen, Bennett and Kemler utilized the forced-choice
method in an experimental study investigating psycho-physio-
logical feelings. They proposed that one of the greatest
advantages of the method was its versatility in obtaining
responses for many purposes in a variety of situations.
The subjects were presented with stimulus words describing
fifteen different feelings and was "forced" to pattern
these feelings in terms of those most closely and least
closely associated with himself at the moment. It was con
cluded that the study revealed a reasonably high degree of
efficiency and substantial validity in the quantification
of subjective feelings using the forced-choice ranking pro-
-an
cedure.
Various studies by Blackwell, Tanner, Swets and
29D. E. Baier, "Reply to Travers' Article," Psvcho- j
logical Bulletin. XLVIir (September, 1951), 422.
30Patricia S. Allen, Edward M. Bennett and Dorothy
Kemler, Forced-Choice Ranking as a Method for Evaluating
Psvcho-Phvsiolooical Feelings. United States Air Force WADC
Technical Report No. 58-310 (Wright-Patterson Air Force
Base, Ohio, 1959), pp. 1-123.
28
Birdsall, tested sensory discrimination and detection using
the forced-choice procedure. They found that there was good
validity and reliability obtained with this method. An
early study by Blackwell investigated the influence of the
procedures employed to collect threshold psychophysical data
upon two sensory functions. The subjects were required to
discriminate brightness differences with the stimulus size
and the brightness of the background field. This discrimin
ation task utilized both the semantic indicator '(yes-no) and
forced-choice. He found that the yes-no method, when using
group stimuli offers the opportunity for the subject to make
invalid responses. Channelization during this method be
comes apparent. Positive channelization occurs because the
subjects conclude that the predominant response is "yes" and
negative channelization occurs if the subject concludes that
the predominant response is "no." Blackwell has shown that
the opportunity for response channelization is not present
with the forced-choice method. He points out, however, that
there is no direct way to establish which of the two methods
employed gives the "correct" threshold, but this could be
established by corroborative evidence from other kinds of
measurements. He concluded that the use of the semantic
29
I
report with grouped stimuli can lead to invalid data.^
Goldiamond investigated subliminal visual perception
using forced-choice and psychophysical judgments. He found
that accuracy above the level of chance exceeded the psycho-
32
physical threshold.
Previous experiments cited used both visual and
auditory stimuli for testing the differences in thresholds
obtained using the two psycho-physical methods in an effort
to evaluate the reliability and validity of the responses.
The value of the forced-choice technique as a clinical tool
for routine sensory threshold determination had not been
explored.
I ekes devised an accuracy indicator (forced-choice)
which was compared to a semantic indicator for clinical
audiometry. He found that a mean threshold approximately
5 db lower could be expected when using the accuracy indica-*
tor. Twenty adult males with hearing acuity within normal
limits were used as subjects. A T-pad inserted into the
headphone o£ a clinical audiometer insured additional
•^Blackwell, "The Influence of Data Collecting Pro
cedures . . . ," loc. cit., pp. 306-315.
32Goldiamond, "The Relationship of Subliminal Per
ception . . . loc. cit.. pp. 378-379.
30
attenuation for this sub-threshold investigation. Four
lights were mounted on a panel and numbered one to four.
This panel was visible to subjects during the test procedure
and was employed to indicate time sequences to the subjects.
The subjects were instructed to report which light was on
when the sound was present. The frequencies 512 and 2048
were the test stimuli. The subject was forced to respond
even if he had to guess. Exploration was accomplished by
manipulating a 5 db step attenuator. A descending technique
was used for both the accuracy and semantic indicator in
establishing the auditor thresholds. Determination of
chance response indicated that three or four correct re
sponses out of four possibilities would be accepted as in
dicating the presence of hearing. Subjects receiving the
experimental condition first scored lower than those re
ceiving the conventional condition test first. This was
ascribed to subject response bias associated with the se
mantic indicator. Subjects receiving the conventional test
first were more conservative in reporting the presence of a
weak stimulus.^
Ickes reported a mean threshold difference of 4.25
^Ickes, loc. cit. . pp. 144-149.
db between the two indicators. The group given the accuracy!
indicator first revealed a mean threshold difference of 2.0
* ;
db and those receiving the semantic indicator first showed
a mean threshold difference of 6.5 db. It is interesting
to note this small difference in mean threshold when the
forced-choice technique was employed first as it would indi
cate that possibly these are not sub-threshold measurements
but closer to the true threshold values. Blackwell pointed
out that it is difficult to determine which method reveals
the "correct" threshold.-*4 Ickes' findings allow one to
postulate that perhaps the accuracy indicator permits more I
accurate threshold measurements by eliminating as much as
I
possible subject bias and that thresholds established using
this psycho-physical method are "correct" thresholds.
The results of these investigations suggest the need
for evaluating the application of this forced-choice tech
nique to other threshold measurements utilized in audiolog-
ical assessment. Although the experiments discussed on the
preceding pages compared the forced-choice method with the
method of limits, Dember states that the forced-choice re
sponse is for the most part incompatible with the assum£>-
34Blackwell, "The Influence of Data Collecting Pro
cedures . . . ," loc. cit.. p. 311.
tions basic to tbe method of limits. The forced-choice and
method of constant stimuli are the best combination.^
In 1960 a study was completed employing the two
methods for determining thresholds of intelligibility on
normal hearing subjects, the forced-choice and method of
constant stimuli. Speech intelligibility thresholds in
noise using the forced-choice indicator were found to be
significantly lower than those obtained using the yes-no
indicator. The mean difference between the thresholds ob
tained using the two indicators was less than 1 db. The
experimenter found that there was a decrease in time re
quired to establish speech intelligibility threshold using
the forced-choice indicator compared to the time required
36
to establish thresholds using the semantic indicator.
Various psychophysical methods have been adapted
for audiological assessment of acuity. These include the
method of limits, method of adjustment, and the method of
constant stimuli. A fourth psychophysical method, forced-
choice, shows good potential for clinical auditory threshold
measurement. Psychological and audiological experimental
■^William N. Dember, The Psychology of Perception
(New York: Henry Holt and Co., 1960), p. 39.
3^Smith, op. cit., pp. 1-11.
33
research reviewed reflect results which indicate that this
method permits threshold measurement which is not influenced;
by variables extraneous to sensory discrimination and yield
greater validity and session-to-seasion, test-retest consis
tency. The literature also revealed that the most compat
ible techniques would be the combination of forced-choice
and constant stimuli. One study applied these two tech
niques to a population of normal hearing subjects. It was
suggested that exploration with hypoacusic subjects would
be significant to the study of these psychophysical methods.
CHAPTER III
SUBJECTS, MATERIALS, PROCEDURES
Sufa-iects
The test population consisted of twenty subjects
with conductive and twenty subjects with sensori-neural
types of hearing loss.
Subject variables of hearing loss, discrimination,
language, age, and reading ability were controlled.
Subjects in the conductive loss group were required
to meet the following audiometric criteria: (1) no less
than a 20 db loss and no more than a 60 db loss for fre
quencies 500 cps, 1,000 cps, and 2,000 cps, (2) bone conduc
tion thresholds within the normal range with no more than a
15 db loss at any of the speech frequencies, and evidence of
an air-bone gap, (3) speech intelligibility thresholds no
less than 20 db and no more than 64 db, and (4) speech dis
crimination scores between 90 and 100 per cent.
The audiometric criteria for subjects in the sen-
sori-neural loss group were: (1) no less than a 15 db loss
for frequencies 500 cps, 1,000 cps, and 2,000 cps, (2) bone
________________.34__________________________
35
conduction thresholds revealed no air-bone gap, (3) speech
intelligibility threshold no less than 16 db, and (4) speech!
discrimination scores must fall between 50 and 100 per cent.
An otological examination was completed on all sub
jects which included the history relative to onset of the
hearing loss, etiology, and diagnosis of the type of hearing
loss. The conductive group included eight subjects with a
medical history of otitis media and twelve with a diagnosis
of otosclerosis. The sensori-neural group consisted of ten
subjects with acoustic trauma, a history of concussion in
two cases, possible virus in two cases, and unknown etiologyj
in six cases.
Bekesy tracings were obtained on all subjects to aid
in the classification of the possible location of the le
sion. The tracings were categorized by a panel of three
judges as Type I, II, III or IV (according to Jerger's
description).^
The distribution of the Bekesy tracings according
to etiology of hearing loss is shown in Table 1.
The conductive hearing loss group consisted of
twenty subjects and the same number in the sensori-neural
1James Jerger, loc. cit.. pp. 275-287.
36
TABLE 1
DISTRIBUTION OP BEKESY TRACINGS
ACCORDING TO ETIOLOGY OP HEARING LOSS
f
Etiology of
Hearing Loss
Type I Type II Type III Type IV Total
Otoscleros is 10 2 0 0 12
Otitis Media 8 0 0 • 0 8
Acoustic Trauma 0 10 0 0 10
Concussion 1 1 0 0 2
Virus 1 1 0 0 2
Unknown 5 1 0 0 6
Total 25 15 0 0 40
i
37
I
hearing loss group. The age ranged from 18 to 60. The mean
age was 42.2.
All subjects demonstrated general American speech,
precluding any variation in lingual background that might
affect the obtained measures.
Gray's Oral Reading Test for the 5th grade level
was administered to all subjects to assure their ability to
read the cue card and written instructions for the various
2
tasks. All subjects satisfied this criterion.
Materials
The test stimuli were recorded by an experienced
male speaker on magnetic tape. The spondee word list used
in determining the speech intelligibility threshold (yes-no
indicator) was made up of randomized spondaic words chosen
from PAL Auditory Test Mo. 9 lists I and II. * * These lists
were chosen as they permitted greater selection and random
ization of eighty-four spondee words rather than the thirty-'
six available in the W-2 list. The stimuli on this tape
were also used for the establishment of Speech Detection
2W. S. Gray, Standardized Oral Reading Paragraphs
(Bloomington, Illinois: Public School Publishing Co.,
1957), pp. 1-4.
3Hirsh, op. cit.. pp. 328-329.
38
Thresholds. A 1,000 cps calibration tone preceded the taped
mater ial.
Forty lists were made up of five randomly selected
words. From each of these lists one word was randomly se
lected. These forty words comprised the force-choice test
I
stimuli. The forty lists were typed on 5"x8" cards and
numbered in the upper right hand corner of the card.
These words were also recorded on magnetic tape for
one of the tasks. Each word was preceded by the verbal com
mand "Listeni" and followed by the command "GuessI" Presen
tations of stimuli were varied to rule out rhythm and sub
jects' ability to anticipate presentation of the test words.
At the beginning of every sixth word list the subject was
informed of the list number so that errors in card rotation
could be detected. The grouped sequences were no more than
nine seconds in length with no less than three, and no more
than six seconds between a command and the test stimuli.
The total test time for the full forty wbrds was twelve min
utes and forty-five seconds. The position of each word on
sequential subject cards was randomized.
Equipment
The Allison 21B Auditory Test Unit with TDH 39
39
receivers and MY 41AR cushions was used for all threshold
determinations. A Berlant Concertone Tape Recorder, Model
BRX, was used with the Allison 21B for recording the tapes
and presenting test stimuli. This tape recorder has a fre
quency response of - 2 db from 50 to 12,000 cps at 7 1/2
ips.
The Grason-Stadler Bekesy Audiometer Model E800 was
used for the Bekesy tracings. One octave per second fre
quency change and 2.5 db per second attentuation change
(reported by Jerger) was used. The pulsed tone was inter-
rupted 2.5 times per second. The frequency exploration of j
100 to 10,000 cps represented the limits of the audiometer.
All equipment used in the study was calibrated daily
to assure reliability of performance.
Environment
Testing was conducted in a two-room acoustically
isolated audiometric test suite at the Veterans Administra
tion Outpatient Clinic, Los Angeles. Lighting, subject po
sitioning, and ventilation were the same for each test.
Ambient noise level for the subject room as measured on a
Soundscope Sound Level Meter and Analyzer Model A was 26 db
(above 75 cps).
Procedure
Bekesy tracings were obtained on subjects prior to
the three tasks. The following instructions were given to
the subjects.
You will be tested twice with this automatic audio
meter. The first test will consist of a pulsed tone
(Beep-beep-beep). Whenever you are sure you hear this
pulsed tone press the lever. Keep it down as long as
you hear the pulsed tone and release it when you no
longer hear it.
The second test will consist of a continuous tone
(Beeeeeeeeep). Follow the same procedure by depressing
the lever as long as you can hear the tone and releas
ing it when you no longer hear it.
The order of presentation of the following tasks
4
was counter-balanced to control the order effect. This is
shown in Table 2. All test stimuli were introduced raonaurr
ally through the headphones to the subjects. The ear se
lected was the one which best met audiometric criteria.
Establishment of speech detec
tion threshold using ves-no
indicator
This threshold of detectability was obtained by
having the subjects raise their finger when they first
heard the sound stimuli and lower their finger when they
^E. F. Lindquist, Design and Analysis of Experiments
in Psychology and Education (Boston: Houghton Mifflin Co.,
1953), pp. 162-163.
41
TABLE 2
COUNTER-BALANCE DESIGN FOR THE STUDY
Subjects Task I Task II Task III
1,
25,
7, 13, 19,
31, 37 SDT SIT FCT
2,
26,
8, 14, 20,
32, 38 « SDT FCT SIT
3,
27,
9, 15, 21,
33, 39 SIT SDT FCT
4,
28,
10, 16, 22,
34, 40 FCT SDT SIT
5,
29,
11, 17, 23,
35 SIT FCT SDT
6,
30,
12, 18, 24,
36 FCT SIT SDT
42
could no longer "hear it. The instructions for the task
m
were:
This test will utilize two-syllable words. Just as
soon as you think you hear something, raise your finger.
Keep it up as long as you hear something and lower it
when you can no longer hear anything. Do not wait until
you can understand the words. Raise your finger when
you think you can detect a noise and lower it when you
can no longer detect it.
Exploration began below the best threshold for pure
tones. The intensity was increased in 2 db steps until a
response was obtained from the subject. The threshold of
speech detection was recorded as that level at which the
subject indicated he just detected the stimuli 50 per cent
of the time.
Rstahlishment of speech intelli
gibility threshold using ves-no
indicator
Speech intelligibilty thresholds were obtained mon-
aurally using the yes-no method. The ear selected was the
one satisfying the criteria stated in the discussion of sub
ject control. In the case of a symmetrical loss, the ear in
which the hearing aid was worn was selected.
The subjects were given the following written in
structions :
Here is a list of the words which I will give you
during the test. Please study these words for the next
43j
five minutes so that you will become familiar with them.,
The subjects were then handed the alphabetized list to studyj
for five minutes (see Appendix C).
The subjects were then required to read the follow
ing instructions:
Now we will begin the test. I will give you these
two-syllable words. Just as soon as you hear them,
repeat them back to me. If you hear "cowboy" repeat
aloud "cowboy." These words will be very soft. You
will have to strain to hear them, but just as soon as
you can make them out, repeat them. Do you have any
questions?
Since all of the subjects had experienced this test in the
initial battery, they were familiar with this procedure.
The threshold for this task was also obtained with
eaqplorations beginning below threshold with the intensity
increased in 2 db steps. The intensity at which the subject;
responded correctly to 50 per cent of the words was recorded
as the threshold of speech intelligibility.
Establishment of speech intelli
gibility threshold using forced-
choice indicator
This threshold measurement was obtained by having
the subject guess aloud which of five words appearing on
the card he held in his hand was the test word. The in
structions for this task were as follows:
44
There are five words listed on each card. At the
top of each card the number of the card is indicated.
Before each test word is given, you will hear a man's
voice saying, "Listen!" This is your signal to be
attentive as the test word will soon follow. Following
the test word you will hear the command "Guess!" Upon
this command select the word that you think was given
and repeat it aloud. You must guess after each command
whether you were aware that you heard a word or not.
After selecting a word from the list, rotate the card
to the back. You are then ready for the next test ser-.
ies. At certain intervals the list number will be given
to make sure you have rotated the card to the correct
list. If you find a discrepancy, notify the examiner
immediately. Remember, vou must respond with a selected
word after the command "Guess!"
The written instructions were reinforced by a verbal review
of the sequence of the task and the subjects were reminded
that they must guess which word was said even though they
were not consciously aware they heard anything. It was
necessary to review these instructions during the test per
iod for three subjects.
The verbal commands of the test series were given
20 db above the level of the known Speech Reception Thresh
old. The investigation of the forced-choice threshold began
2 db below the speech detection threshold, if known, or 2 db
below the best pure tone threshold. Increments were made in
2 db steps until that sensation level at which better-than-
chance guessing was obtained. Three more trials were given
at the same level to satisfy the criteria of better-than-
45
i
chance guessing. The criteria for better-than-chance guess
ing were that the subject answer correctly two out of two,
three out of three, or three out of four words, using four
trials at each level. The experimenter could draw the con
clusion that the subject did better-than-chance at the five
per cent level of confidence.^
The forced-choice task was repeated after a rest
period of fifteen minutes to evaluate the reliability of
session-to-session thresholds. A new order of sequence was
used for each subject. 1
Gilford J. Dixon and Frank J. Massey, Introduction1
to Statistical Analysis (New York: McGraw-Hill Book Com
pany, Inc., 1957), p. 466,
4
CHAPTER IV
*
PRESENTATION AND INTERPRETATION
OF THE DATA
In order to determine whether differences exist be
tween two psychophysical methods of obtaining speech intel
ligibility thresholds on hard of hearing subjects, it was
hypothesized that there would be no significant differences
in thresholds obtained on the same subjects using both the
forced-choice and the yes-no indicators. During the experi
ment. thresholds were measured and recorded for each of the
tests previously described. These threshold measurements
were treated statistically in order to discover whether dif
ferences existed between (1) Speech Intelligibility Thresh
olds and Forced-Choice Thresholds, (2) Speech Detection
Threshold and Forced-Choice Threshold, (3) Forced-Choice
Threshold, First Session and Forced-Choice Threshold, Second
Session, and (4) two organic hearing loss groups, i.e. con
ductive and sensori-neural. The test population consisted
of twenty subjects with conductive and twenty subjects with
f
sensori-neural types of hearing loss.
_____________46______________
Statistical Procedure
«
A mixed analysis of variance (Lindquist Type I) was
performed to determine whether there were nonchance varia
tions or interactions among means. It was predetermined
that if F-ratios were significant at the five per cent level
then specific comparisons with the t test would be made.1
Pearson product-moment correlations were obtained between
the speech thresholds to determine whether causal relation
ships existed between the tests and whether there were sig
nificant differences between the correlations of the two
groups for the same test.2
Analysis of the Data
The results of the analysis of variance revealed
the main effect of tests to be statistically significant at
p ^ .01. No other main effect or interaction was statisti
cally significant. The results of this analysis are pre
sented in Table 3.
Since the analysis of variance revealed that there
Lindquist, op. cit. . p. 269.
2J. P. Guilford, Fundamental Statistics in Psychol
ogy and Education (New York: McGraw-Hill Book Company,
Inc., 1956), p. 138.
48
TABLE 3
ANALYSIS OF VARIANCE AMONG MEANS
Source
Sum of
Squares
df
Mean
Square
F P
Between Ss 10,019.6 39
Groups 220.9 1 220.9 <1. N.S.
Error (b) 9,798.7 38 257.86
Within Ss 3, 068.0 120
Tests 2, 024.6 3 674.87 77. 22 <.01
Groups x Tests 46.9 3 15.63 1.79 N.S.
Error (w) 996.5 114 8.74
Total 13,087.6 159
were nonchance variations among means of the tests, the
test for difference between correlated pairs of means was
applied to determine whether the hull hypotheses should be
3
accepted or rejected.
Hypothesis I stated that no differences would exist
between speech intelligibility thresholds obtained on the
same hard of hearing individual using the two types of indi
cators of perception. This hypothesis was rejected at the
.01 level of confidence as the results of the t. test indi
cated that there was a significant difference between the
means of the thresholds obtained by the two indicators. j
Table 4 summarizes the results of the .t test for related
measures of the two indicators reflected by SIT and FCT#1
and SIT and FCT#2.
Previous research using the forced-choice technique
stated lower thresholds were obtained by this method. It
seemed possible therefore that the subjects might attain
better-than-chance guessing during the forced-choice thresh
old measurement at the same level at which speech was just
detected fifty per cent of the time.
Hypothesis. II stated that no differences would
^Ibid.. p. 220.
TABLE 4
RESULTS OF THE t TEST FOR RELATED MEASURES OF SPEECH
INTELLIGIBILITY THRESHOLDS USING THE TWO INDICATORS
Test
Mean*
(db)
Dif f.
(db)
t p
SIT 41.6
3.8 6.45 <.01
FCT#1 37.8
SIT 41.6
- »
4.8 7.14 •C . 01
FCT#2 36.8
-
*Mean threshold values re audiometric 0 for speech.
51
exist between the speech detection threshold and the level
at which better-than-chance guessing was obtained on the
same hard of hearing individuals. The t. test revealed that
there was a significant difference between the means of the
SDT and FCT#1 and SDT and FCT#2 beyond the .01 level of con-*
fidence. Hypothesis XI, which stated that there would be
no significant differences obtained between these two meas
urements was, therefore, rejected. The results of the t_
test for these related measures are shown in Table 5.
Hypothesis 111 stated that no difference would exiBti
between means of the session-to-session forced-choice
thresholds. The t. test indicated that there was a signifi
cant difference between the means of session-to-session
forced—choice thresholds beyond the .01 level of confidence^
Hypothesis III was rejected. Table 6 summarizes the results
of the t, test for these related measures.
It should be noted that although a significant dif
ference was found between the speech intelligibility
thresholds obtained using the two methods, the mean differ
ences were 3.8 db between SIT and FCT#1 and 4.8 between SIT :
and FCT#2. These mean differences are similar to those
found by Iekes, who reported a mean threshold difference
between the two methods of 4.25 db using pure tones as the
TABLE 5
RESULTS OF THE t. TEST FOR RELATED MEASURES
OF THE SDT AND FCT#1 AND SDT AND FCT#2
Test
Mean*
(db)
Diff.
(db)
t P
SDT
FCT#1
31.6
37.8
6.2 11.02 <.01
SDT 31.6
5.2 8.26 < .01
FCT#2 36.8
TABLE 6
RESULTS OF THE t TEST FOR RELATED MEASURES
OF THE FCT#1 AND FCT#2
Test
Mean*
(db)
Diff.
(db)
t . P
FCT#1 37.8
1.0 3.94 <.01
FCT#2 36.8
•Mean threshold values re audiometric O for speech.
53
4 I
stimuli. Smith, applying the forced-choice technique for
establishing thresholds in noise on thirty normal hearing
subjects found a mean difference of .9 db.5 These reported
differences between the threshold means obtained using the
two indicators are all less than present clinical error ex
pected for test-retest and session-to-session thresholds
using the yes-no technique.
Lukaszewski and Elliott tested normal hearing sub-
1
jects using a forced-choice procedure in establishing pure
i
tone thresholds. They found that thresholds obtained using j
j
the forced-choice technique were poorer than those obtained
under no-forced-choice instructions. In their procedure it
was not mandatory for the subject to respond if he felt un
able to do so. This procedure does not conform'to the defi
nition of forced-choice technique, as it permitted bias on
the part of the subjects in allowing them to decide whether j
i
to respond or not. This probably was the cause for their
findings of poorer thresholds using the forced-choice meth
od. The use of feedback (informing the subject of correct
ness of response) during the forced-choice procedure subse-
4Ickes, loc. cit., p. 148.
5Smith, op. cit.. pp. 1-11.
: _
54
q u e n t l y p r o d u c e d a m e a n t h r e s h o l d t h a t w a s 3 . 4 d b l o w e r t h a n
t h e n o f e e d b a c k g r o u p .
H y p o t h e s i s I V s t a t e d t h a t t h e r e w o u l d b e n o s i g n i f i
c a n t d i f f e r e n c e s b e t w e e n t h e t w o o r g a n i c g r o u p s , i . e . c o n
d u c t i v e a n d s e n s o r i - n e u r a l , u s i n g a n y o f t h e s p e e c h t e s t s .
T h e a n a l y s i s o f v a r i a n c e d i d n o t r e v e a l a n y n o n c h a n c e v a r i
a t i o n s b e t w e e n t h e t w o g r o u p s . P e a r s o n p r o d u c t —m o m e n t c o r
r e l a t i o n s f o r t h e c o m p a r i s o n s o f t h e t w o g r o u p s o n a l l o f
t h e s p e e c h t h r e s h o l d s w e r e c o m p u t e d . T h e t e s t o f d i f f e r
e n c e s b e t w e e n t h e r 1 s w a s a p p l i e d t o t h e c o r r e l a t i o n s o f
t h e t e s t w h i c h s h o w e d t h e l a r g e s t d i f f e r e n c e b e t w e e n g r o u p s .
N o s i g n i f i c a n t d i f f e r e n c e s w e r e f o u n d b e t w e e n t h e c o r r e l a
t i o n s o f t h e t w o g r o u p s . H y p o t h e s i s I V w a s a c c e p t e d .
T a b l e 7 s u m m a r i z e s t h e r e s u l t s o f t h e z_ a n d t h e c o e f f i c i e n t
o f c o r r e l a t i o n s f o r t h e c o m p a r i s o n s b e t w e e n t h e t h r e s h o l d s
o b t a i n e d u s i n g t h e t w o i n d i c a t o r s f o r t h e t w o g r o u p s a n d
groups combined.
A l t h o u g h t h e r e w a s a s l i g h t l y l a r g e r m e a n d i f f e r
e n c e i n t h e s e n s o r i - n e u r a l g r o u p , i t s h o u l d b e n o t e d t h a t
s . L u k a s z e w s k i and D . N . Elliott, "Auditory
T h r e s h o l d a n d a F u n c t i o n o f F o r c e d - C h o i c e T e c h n i q u e , F e e d
b a c k a n d M o t i v a t i o n , " J o u r n a l o f t h e A c o u s t i c a l S o c i e t y o f
A m e r i c a . X X X I V (February, 1 9 6 2 ) , 2 2 3 — 2 2 8 .
^Guilford, op. cit., p. 194,
55
t h e c o r r e l a t i o n o f t h i s g r o u p i s s l i g h t l y h i g h e r . T h i s
g r o u p h a d a l o w e r m e a n F C T # 1 t h a n d i d t h e c o n d u c t i v e g r o u p .
T h d s e c o r r e l a t i o n s i n d i c a t e h i g h c o r r e l a t i o n s w i t h a m a r k e d
r e l a t i o n s h i p . H i g h c o r r e l a t i o n s w e r e a l s o f o u n d i n t h e c o m
p a r i s o n s o f S I T w i t h F C T # 2 p r e s e n t e d i n T a b l e 8 .
T h e m e a n d i f f e r e n c e f o r a l l m e a s u r e m e n t s i s a p p r o x
i m a t e l y 1 d b g r e a t e r t h a n w a s o b s e r v e d b e t w e e n S I T a n d
F C T # 1 . A g a i n t h e s e n s o r i — n e u r a l g r o u p p r o d u c e d t h e l a r g e s t
m e a n d i f f e r e n c e . T h e c o r r e l a t i o n s w e r e h i g h e s t f o r t h e c o n
d u c t i v e g r o u p ; h o w e v e r , t h e c o r r e l a t i o n s f o r t h e c o m b i n e d
g r o u p w e r e . 8 5 f o r t h e c o m p a r i s o n s b e t w e e n S I T a n d F C T # 1
a n d S I T a n d F C T # 2 .
The correlation of the speech detection t h r e s h o l d s
and the two forced-choice thresholds was then computed.
P r e v i o u s research has shown that the speech detection
t h r e s h o l d i s 6 t o 9 d b l e s s t h a n t h e s p e e c h i n t e l l i g i b i l i t y
O Q
t h r e s h o l d . ' T h e s t u d i e s o f B l a c k w e l l r e v e a l e d t h a t
f o r c e d - c h o i c e t h r e s h o l d s w e r e l o w e r t h a n t h o s e t h r e s h o l d s
8C h a i k l i n , l o c . c i t . , p p . 2 2 9 - 2 4 3 .
9 W . R . T h u r l o w e t a l . , " A S t a t i s t i c a l S t u d y o f A u d
itory Tests in Relation to the Fenestration Operation," The
Laryncroscope, LVIII ( J a n u a r y , 1 9 5 8 ) , 5 7 .
56
T A B L E 7
R E S U L T S O F T H E P E A R S O N P R O D U C T - M O M E N T C O R R E L A T I O N
C O E F F I C I E N T S A N D T H E z . T E S T O F D I F F E R E N C E S
B E T W E E N r ' s F O R T H E F C T # 1 A N D S I T
G r o u p
M e a n *
D i f f . r_
i
|N
S I T F C T # 1
C o n d u c t i v e 4 1 . 8 3 9 . 2 + 2.6 . 8 2 <.01
. 6 7 N . S .
S e n s o r i - N e u r a l 4 1 . 3 3 6 . 5 + 4 . 8 . 88 <.01
C o m b i n e d 4 1 . 6 3 7 . 8 + 3 . 8 . 8 5 <.oi
T A B L E 8
R E S U L T S O F T H E P E A R S O N P R O D U C T - M O M E N T C O R R E L A T I O N
C O E F F I C I E N T S F O R T H E F C T # 2 A N D S I T
G r o u p
M e a n *
D i f f . . r P
S I T F C T # 2
C o n d u c t i v e 4 1 . 8 3 8 . 3 + 3 . 5 . 88 < . 01
S e n s o r i - N e u r a l 4 1 . 3 3 5 . 3 + 6.0 . 8 5 < . 01
C o m b i n e d 4 1 . 6 3 6 . 8 + 4 . 8 . 8 5 < .01
*Mean threshold values re audiometric 0 for speech.
57
o b t a i n e d u s i n g t h e s e m a n t i c i n d i c a t o r . ^ M u c h o f t h i s r e
p o r t e d r e s e a r c h w i t h t h e f o r c e d - c h o i c e m e t h o d h a s b e e n i n
a u d i t o r y a n d v i s u a l s i g n a l d e t e c t a b i l i t y . ^ ^
A l t h o u g h t h e m e a n d i f f e r e n c e s b e t w e e n s p e e c h d e t e c t i o n
t h r e s h o l d s w e r e f o u n d t o b e s i g n i f i c a n t l y d i f f e r e n t ( S D T
l o w e r t h a n F C T ) i n t h i s s t u d y , t h e r e w a s a h i g h c o r r e l a t i o n
f o u n d b e t w e e n t h e s e t w o t h r e s h o l d s . T a b l e 9 s h o w s t h e r e
s u l t s o f t h e r . f o r t h e c o n d u c t i v e , s e n s o r i - n e u r a l a n d t h e
t w o g r o u p s c o m b i n e d . T h e s t a b i l i t y o f t h e r e l a t i o n s h i p o f
t h e m e a n d i f f e r e n c e s b e t w e e n t h e g r o u p s f o r t h e s e t h r e s h o l d s
i s n o t a b l e .
■ ^ B l a c k w e l l , l o c . c i t . , p p . 3 0 6 - 3 1 5 .
- * - - * - L u k a s z e w s k i a n d E l l i o t t , l o c . c i t . , p p . 2 2 3 - 2 2 8 .
1 2C . D . C r e e l m a n , D e t e c t i o n o f S i g n a l s o f U n c e r t a i n
F r e q u e n c y , T e c h n i c a l M e m o r a n d u m N o . 7 1 , D e p a r t m e n t o f E l e c
t r i c a l E n g i n e e r i n g ( A n n A r b o r : U n i v e r s i t y o f M i c h i g a n R e
s e a r c h I n s t i t u t e , 1 9 5 9 ) .
a . S w e t s , " I n d i c e s o f S i g n a l D e t e c t a b i l i t y O b
t a i n e d w i t h V a r i o u s P s y c h o p h y s i c a l P r o c e d u r e s , " J o u r n a l o f
A c o u s t i c a l S o c i e t y o f A m e r i c a . X X X I ( A p r i l , 1 9 5 9 ) , 5 1 1 - 5 1 3 .
P . T a n n e r , J r . a n d J . A . S w e t s , " A D e c i s i o n
M a k i n g T h e o r y o f V i s u a l D e t e c t i o n , " P s y c h o l o g i c a l R e v i e w ,
L X I ( N o v e m b e r , 1 9 5 4 ) , 4 0 1 - 4 0 9 .
^ 5 J . A . S w e t s , W . P . T a n n e r , J r . a n d T . G . B i r d s a l l ,
T h e E v i d e n c e f o r a D e c i s i o n - M a k i n g T h e o r y o f V i s u a l D e t e c
t i o n , E l e c t r o n i c D e f e n s e G r o u p T e c h n i c a l R e p o r t N o . 4 0 ( A n n
A r b o r : U n i v e r s i t y o f M i c h i g a n , 1 9 5 5 ) .
58
T A B L E 9
R E S U L T S O F T H E P E A R S O N P R O D U C T - M O M E N T
C O R R E L A T I O N C O E F F I C I E N T S F O R T H E F C T # 1 A N D S D T
G r o u p
M e a n
*
D i f f . r . P
S D T F C T # 1
C o n d u c t i v e 3 3 . 2 3 9 . 2 - 6.0 . 8 5 < .01
S e n s o r i - N e u r a l 3 0 . 0 3 6 . 3 - 6 . 3 . 8 5 < .01
C o m b i n e d 3 1 . 6 3 7 . 8 - 6.2 . 8 5 < .01
* M e a n t h r e s h o l d v a l u e s r e a u d i o m e t r i c 0 f o r s p e e c h .
59
T h e t w o g r o u p s s h o w e d a d i f f e r e n c e b e t w e e n t h e m e a n s
o f S D T a n d F C T # 1 o r 6 a n d 6 . 3 d b r e s p e c t i v e l y . T h i s d i f f e r
e n c e i s g r e a t e n o u g h f o r u s t o a s s u m e t h a t a l t h o u g h t h e s u b
j e c t s h a d a c a r d w i t h t h e l i s t o f w o r d s i n f r o n t o f t h e m , i t
w a s n o t p o s s i b l e f o r t h e m t o a c h i e v e b e t t e r - t h a n - c h a n c e
g u e s s i n g w i t h t h e c l u e s a v a i l a b l e a t t h e s p e e c h d e t e c t i o n
l e v e l .
A s . w a s f o u n d i n t h e c o m p a r i s o n s b e t w e e n S D T a n d
F C T # 1 , t h e r e i s a m a r k e d s t a b i l i t y i n t h e d i f f e r e n c e b e
t w e e n t h e m e a n s o f S D T a n d F C T # 2 o f t h e t w o g r o u p s . A g a i n
t h e c o r r e l a t i o n b e t w e e n t h e t w o t h r e s h o l d s w a s v e r y h i g h , a s
c a n b e s e e n i n T a b l e 1 0 .
I t w a s t h e n a d v i s a b l e t o o b s e r v e w h e t h e r t h e r e l a
t i o n s h i p o f S I T t o S D T w a s s i m i l a r . T h e r e s u l t s o f t h e r .
b e t w e e n t h e s e t h r e s h o l d s r e v e a l e d a v e r y h i g h c o r r e l a t i o n
a n d a r e s h o w n i n T a b l e 1 1 .
Thurlow et al. reported an average difference of
5.5 db between the speech detection thresholds and speech
intelligibility thresholds obtained or. subjects with oto
sclerosis. The speech detection thresholds were found by
them to be lower (better) than the speech intelligibility
60
TABLE 10
R E S U L T S O F T H E P E A R S O N P R O D U C T - M O M E N T C O R R E L A T I O N
C O E F F I C I E N T S F O R T H E S D T A N D F C T # 2
G r o u p
M e a n *
D i f f . r_ P
S D T F C T # 2
C o n d u c t i v e 3 3 . 2 3 8 . 3 - 5 . 1 . 8 5 < .01
S e n s o r i - N e u r a l 3 0 . 0 3 5 . 3 - 5 . 3 . 8 5 *
o
H
C o m b i n e d 3 1 . 6 3 6 . 8 - 5 . 2 . 8 5 <.01
T A B L E 1 1
R E S U L T S O F T H E P E A R S O N P R O D U C T - M O M E N T C O R R E L A T I O N
C O E F F I C I E N T S F O R T H E S D T A N D S I T
G r o u p
M e a n
*
D i f f . r_ P
S D T S I T
C o n d u c t i v e 3 3 . 2 4 1 . 8 - 8.6 . 9 1 <.01
S e n s o r i - N e u r a l 3 0 . 0 4 1 . 3 - 1 1 . 3 . 88 < - 0 1
C o m b i n e d 3 1 . 6 4 1 . 6 - 10 . 0 . 88 < . 0 1
*Mean threshold values re audiometric 0 for speech.
61
1 ft
t h r e s h o l d s . O f t h e t w e n t y c o n d u c t i v e s i n t h e p r e s e n t
s t u d y , t w e l v e h a d b e e n d i a g n o s e d a s o t o s c l e r o t i c . T h e s e
t w e l v e c o n f o r m e d w e l l w i t h t h e t o t a l g r o u p o f c o n d u c t i v e s
w i t h 8.8 d b d i f f e r e n c e b e t w e e n t h e s p e e c h d e t e c t i o n a n d
s p e e c h i n t e l l i g i b i l i t y t h r e s h o l d s w h e n c o m p a r e d t o t h e 8.6
d b m e a n d i f f e r e n c e o f . t h e c o n d u c t i v e g r o u p . T h e s e d i f f e r
e n c e s a g r e e f a i r l y w e l l w i t h E g a n ' s f i n d i n g s o f 1 9 4 8 . H i s
s t u d y s h o w e d a d i f f e r e n c e o f 12 d b b e t w e e n t h e t h r e s h o l d o f
1 7
i n t e l l i g i b i l i t y a n d t h e t h r e s h o l d o f d e t e c t a b i l i t y .
T h e m e a n d i f f e r e n c e s b e t w e e n F C T # 1 a n d F C T # 2 w e r e
f o u n d t o b e s i g n i f i c a n t l y d i f f e r e n t i n s e s s i o n - t o - s e s s i o n
t e s t i n g . - T h e m e a n s o f F C T # 2 a r e a p p r o x i m a t e l y 1 d b l e s s
t h a n t h e m e a n s o f F C T # 1 . I c k e s a n d B l a c k w e l l r e p o r t t h a t
f o r c e d - c h o i c e t h r e s h o l d s a r e b e t t e r ( l o w e r ) a f t e r i n i t i a l
t r i a l .18,19
T h i s 1 d b d i f f e r e n c e i s p o s s i b l y d u e t o e d u c a t i o n
o n t h e p a r t o f t h e s u b j e c t s a n d f a m i l i a r i t y w i t h t h e p r o
c e d u r e . T h e c o r r e l a t i o n o f t h e s e s s i o n - t o - s e s s i o n t h r e s h -
1 6 T h u r l o w e t a l . , l o c . c i t . . p . 5 7 .
17 E g a n , l o c . c i t . . p . 9 8 1 .
^ - ® I c k e s , l o c . c i t . , p p . 1 4 4 - 1 4 9 .
- ^ B l a c k w e l l , " P s y c h o p h y s i c a l T h r e s h o l d s . . . , "
l o c . c i t . , p . 1 9 9 .
62
o l d s w e r e c o m p u t e d a n d f o u n d t o t o e v e r y h i g h . T a t o l e 1 2
s h o w s t h e r e s u l t s o f t h e r . f o r t h e c o n d u c t i v e , s e n s o r i
n e u r a l a n d t h e t w o g r o u p s c o m b i n e d .
T h e s e c o r r e l a t i o n s a r e m u c h h i g h e r t h a n t h o s e r e
p o r t e d b y C a r h a r t i n h i s s t u d y c o m p a r i n g s e s s i o n - t o - s e s s i o n
s p e e c h i n t e l l i g i b i l i t y t h r e s h o l d s u s i n g t h e s e m a n t i c i n d i c a
t o r . H i s d a t a r e v e a l e d c o e f f i c i e n t s o f r e l i a b i l i t y o f
20 . . .
. 7 5 . T h e s e f i n d i n g s w e r e b a s e d o n l i v e - v o i c e m o n i t o r i n g
o f t h e s t i m u l i w h i c h m a y h a v e i n t r o d u c e d v a r i a b l e s h e l d
c o n s t a n t i n t h e p r e s e n t s t u d y w h e r e t a p e s t i m u l i w e r e u s e d
f o r a l l t h r e s h o l d m e a s u r e m e n t s .
I n t e r p r e t a t i o n
T h e d a t a i n d i c a t e d t h a t l o w e r s p e e c h i n t e l l i g i b i l i
t y t h r e s h o l d s w e r e e s t a b l i s h e d u s i n g t h e f o r c e d - c h o i c e t e c h
n i q u e . T h e m e a n t h r e s h o l d d i f f e r e n c e b e t w e e n t h e t w o m o d i
f i e d p s y c h o p h y s i c a l m e t h o d s f o r t h e c o m b i n e d s u b j e c t s w a s
3 . 8 d b . T h i s d i f f e r e n c e i s w i t h i n t h e p r e s e n t a c c e p t a b l e
c l i n i c a l e r r o r o f -6 d b a n d i n d i c a t e s t h a t t h e i n f o r m a t i o n
r e g a r d i n g m e a s u r e o f h e a r i n g l o s s u s i n g t h e f o r c e d - c h o i c e
i n d i c a t o r i s v a l i d . T h i s i s c o r r o b o r a t e d b y t h e v e r y h i g h
on .
Raymond Carhart, "Monitored Live-Voice as a Test
of Auditory Acuity," Journal of Acoustical Society of Amer
ica, XVII (April, 1 9 4 6 ) , 3 4 7 .
63
T A B L E 1 2
R E S U L T S O F T H E P E A R S O N P R O D U C T - M O M E N T C O R R E L A T I O N
C O E F F I C I E N T S F O R T H E F C T # 1 A N D F C T # 2
G r o u p
M e a n
*
D i f f . r . P
F C T # 1 F C T # 2
C o n d u c t i v e 3 9 . 2 3 8 . 3 - . 9 . 9 3 <. oi
S e n s o r i - N e u r a l 3 6 . 3 3 5 . 3 - 1.0 . 9 8 <.01
C o m b i n e d 3 7 . 8 3 6 . 8 - 1.0 . 9 6 < .01
* M e a n t h r e s h o l d v a l u e s r e a u d i o m e t r i c 0 f o r s p e e c h .
64
c o r r e l a t i o n s f o u n d b e t w e e n F C T a n d S I T , a n d e v o k e s t h e
q u e s t i o n a s t o w h i c h t e c h n i q u e i s " b e t t e r . " T h e s u p p o s i
t i o n t h a t l o w e r t h r e s h o l d s a r e m o r e a c c u r a t e i s m o r e t e n a b l e
t h a n t h e s u p p o s i t i o n t h a t h i g h e r t h r e s h o l d s a r e m o r e a c c u r
a t e . T h e d a t a r e v e a l e d t h a t l o w e r s p e e c h i n t e l l i g i b i l i t y
t h r e s h o l d s w e r e e l i c i t e d u s i n g t h e f o r c e d - c h o i c e i n d i c a t o r
a n d s u p p o r t s t h e h y p o t h e s i s t h a t t h i s i s a b e t t e r m e t h o d o f
t h r e s h o l d m e a s u r e m e n t .
A l t h o u g h t h e r e w e r e n o s i g n i f i c a n t d i f f e r e n c e s
f o u n d a m o n g t h e c o r r e l a t i o n s b e t w e e n S D T a n d S I T a n d S D T
a n d F C T # 1 a n d # 2 , t h e r e w a s a n o t a b l e s t a b i l i t y b e t w e e n t h e
t h r e s h o l d d i f f e r e n c e s o f S D T a n d F C T # 1 a n d # 2 . T h i s s t a b i l
i t y w o u l d i n d i c a t e a m o r e p r e d i c t a b l e r e l a t i o n s h i p b e t w e e n
t h e s e t w o t h r e s h o l d s w h e n u s i n g t h e f o r c e d - c h o i c e t e c h n i q u e
f o r e s t a b l i s h i n g i n t e l l i g i b i l i t y t h r e s h o l d s t h a n i s f o u n d
u s i n g t h e Y e s - N o t e c h n i q u e f o r e s t a b l i s h i n g i n t e l l i g i b i l i t y
t h r e s h o l d s .
C a r h a r t r e p o r t e d a c o r r e l a t i o n o f . 7 5 b e t w e e n s e s
s i o n - t o - s e s s i o n s p e e c h i n t e l l i g i b i l i t y t h r e s h o l d s u s i n g t h e
21
Y e s - N o t e c h n i q u e . T h e e x t r e m e l y h i g h c o r r e l a t i o n o f . 9 6
4
f o u n d b e t w e e n t h e f o r c e d - c h o i c e s e s s i o n - t o - s e s s i o n t h r e s h -
21Ibid.
65
o l d s c o n f i r m s t h e v a l u e o f t h i s t e s t t e c h n i q u e . T h e s e f i n d
i n g s a r e p a r t i c u l a r l y e n c o u r a g i n g f o r m e d i c o - l e g a l t e s t i n g
w h e r e s t a b l e a n d c o n s i s t e n t t h r e s h o l d s a r e m a n d a t o r y f o r
t h e p r o p e r e v a l u a t i o n o f t h e h e a r i n g d i s a b i l i t y .
N o s i g n i f i c a n t d i f f e r e n c e s w e r e f o u n d b e t w e e n t h e
t w o o r g a n i c g r o u p s , i . e . , c o n d u c t i v e a n d s e n s o r i - n e u r a l .
T h e f o r c e d - c h o i c e t e c h n i q u e c a n b e u s e d e f f e c t i v e l y w i t h
e i t h e r g r o u p .
T h e s p e e c h i n t e l l i g i b i l i t y t h r e s h o l d s o b t a i n e d u s i n g
t h e f o r c e d - c h o i c e t e c h n i q u e w e r e l o w e r , m o r e r e l i a b l e a n d
s h o w e d g r e a t e r s t a b i l i t y i n r e l a t i o n t o d e t e c t i o n t h r e s h o l d s
t h a n t h e s p e e c h i n t e l l i g i b i l i t y t h r e s h o l d s f o u n d u s i n g t h e
Y e s - N o t e c h n i q u e .
M a n y o t h e r a t t r i b u t e s o f t h i s m e t h o d w e r e o b s e r v e d
d u r i n g t h e e x p e r i m e n t . B o t h a u d i o l o g i s t a n d s u b j e c t b i a s
i s e l i m i n a t e d . T h e s u b j e c t i s f o r c e d t o r e s p o n d e a c h t i m e
h e i s o r d e r e d t o r e s p o n d . T h e d e c i s i o n o n h i s p a r t t o r e
s p o n d o r n o t h a s b e e n e l i m i n a t e d , t h u s e n a b l i n g b e t t e r s e s
s i o n - t o - s e s s i o n r e l i a b i l i t y . S u b j e c t i n h i b i t i o n w a s d e
c r e a s e d a n d t h e c h o i c e o f w o r d r e s p o n s e w a s r e d u c e d f r o m
e i g h t y - f o u r t o f i v e . S o m e o f t h e s u b j e c t s s t a t e d t h a t t h i s
p r o c e d u r e w a s e a s i e r t h a n t h e y e s - n o i n d i c a t o r . S u b j e c t s
r e p o r t e d h i g h e r c o n f i d e n c e w h e n t h e y h a d t h e w o r d s b e f o r e
66
t h e m . A f e w s u b j e c t s v o i c e d s o m e c o n c e r n a s t o w h e t h e r t h i s
t y p e o f t e s t w o u l d a c c u r a t e l y e v a l u a t e t h e i r h e a r i n g t h r e s h
o l d s . S e v e r a l s u b j e c t s e m p h a s i z e d t h a t t h e r e w e r e m a n y
t i m e s w h e n t h e y m a y h a v e r e s p o n d e d c o r r e c t l y w i t h o u t r e a l l y
" h e a r i n g " t h e w o r d . T h e s u b j e c t s w e r e u s i n g a l l a v a i l a b l e
a u d i t o r y c u e s g i v e n t h e m i n t h e i r d e c i s i o n a s t o w h i c h w a s
t h e c o r r e c t w o r d v i s u a l l y p e r c e i v e d o n t h e c a r d . T h i s d e
c i s i o n p r o c e s s h a s v a r i o u s s t a g e s , a c c o r d i n g t o B r u n e r .
T h e f i r s t s t a g e i n t h e p r o c e s s i s p r i m i t i v e c a t e g o r i z a t i o n .
T h i s r e s u l t s i n t h e p e r c e p t u a l i s o l a t i o n o f a n o b j e c t o r a n
e v e n t w i t h c e r t a i n c h a r a c t e r i s t i c q u a l i t i e s . A n e n v i r o n
m e n t a l e v e n t h a s b e e n p e r c e p t u a l l y i s o l a t e d a n d i s m a r k e d
b y c e r t a i n s p a t i o - t e m p o r a l - q u a l i t a t i v e c h a r a c t e r i s t i c s .
T h e s e c o n d s t a g e i s t h e c u e s e a r c h . T h e s u b j e c t i s
s c a n n i n g t h e c a r d ( d a t a ) t o f i n d c u e s t h a t p e r m i t a m o r e
p r e c i s e r e c o g n i t i o n o r p e r c e p t i o n . T h i s s t a g e i s f o l l o w e d
b y a c o n f i r m a t i o n c h e c k . W h e n a t e n t a t i v e d e c i s i o n h a s
b e e n m a d e t h e n a c o n f i r m a t i o n o f t h i s d e c i s i o n i s s o u g h t i n
t h e f o r m o f a s e a r c h f o r a d d i t i o n a l c u e s . T h e l a s t s t a g e
*
in the process of perceptual identification is .the termina—
tion of cue searching. The sensory in-put has been found
to best "fit" a given category. In this instance the sen
sory in-put was the test word and the category was the word
67
22
s e l e c t e d f r o m t h e f i v e w o r d s o n s u b j e c t s ' c a r d .
T h e r e s u l t s o f t h e t h r e s h o l d d i f f e r e n c e s o b t a i n e d
b e t w e e n t h e y e s - n o ( s e m a n t i c ) a n d t h e f o r c e d - c h o i c e ( a c c u r
a c y ) i n d i c a t o r m a y i n d i c a t e t h a t t h e u s e o f t h e a d d i t i o n a l
c u e s a v a i l a b l e i n t h e f o r c e d - c h o i c e i s o n e r e a s o n f o r t h e
l o w e r t h r e s h o l d s a n d m o r e r e l i a b l e s e s s i o n - t o - s e s s i o n
t h r e s h o l d s . T h e v e r y n a t u r e o f t h e t e c h n i q u e p e r m i t s f e w e r
u n d e s i r a b l e v a r i a b l e s w h i c h a r e e x t r a n e o u s t o s e n s o r y d i s
c r i m i n a t i o n . T h e d e c i s i o n o f r e s p o n d i n g o r n o t r e s p o n d i n g
t o t h e s t i m u l i i s r e m o v e d , t h e r e b y e l i m i n a t i n g o r d e c r e a s
i n g s u b j e c t b i a s . T h e t e c h n i q u e a l s o e l i m i n a t e s e x a m i n e r ' s
\
b i a s b y s e t t i n g u p c r i t e r i a o f s c o r i n g w h i c h c a n n o t b e
m a n i p u l a t e d a s e a s i l y a s t h e p r e s e n t 5 0 p e r c e n t r e s p o n s e
c r i t e r i o n .
^J. S. Bruner, "On Perceptual Readiness," Psycho
logical Review, LXIV (1957), 130-131.
CHAPTER V
S U M M A R Y , C O N C L U S I O N S , I M P L I C A T I O N S
S u m m a r y
T h e p u r p o s e o f t h i s s t u d y w a s t o i n v e s t i g a t e t w o
m e t h o d s o f o b t a i n i n g s p e e c h i n t e l l i g i b i l i t y t h r e s h o l d s o n
h a r d o f h e a r i n g s u b j e c t s , n a m e l y , t h e y e s - n o t e c h n i q u e a n d
t h e f o r c e d - c h o i c e t e c h n i q u e . S u b s i d i a r y p r o b l e m s s t u d i e d
w e r e t h e s e s s i o n - t o - s e s s i o n r e l i a b i l i t y o f t h e f o r c e d -
c h o i c e t e c h n i q u e , t h e d i f f e r e n c e b e t w e e n s p e e c h d e t e c t i o n
t h r e s h o l d s a n d t h e f o r c e d - c h o i c e t h r e s h o l d s a n d w h e t h e r
t h e r e w e r e d i f f e r e n c e s b e t w e e n t h e t w o o r g a n i c g r o u p s i n
t h e u s e o f a n y o f t h e s p e e c h t e s t s .
' T h e l i t e r a t u r e p e r t i n e n t t o t h e p r o b l e m w a s r e
v i e w e d . T h i s l i t e r a t u r e d e a l t p r i m a r i l y w i t h t h e p s y c h o
p h y s i c a l t e c h n i q u e s a d a p t e d f o r u s e i n c l i n i c a l a u d i o m e t r y ,
a r e v i e w o f p r e s e n t m a t e r i a l s a n d m e t h o d s u s e d i n s p e e c h
a u d i o m e t r y f o r t h r e s h o l d a s s e s s m e n t . F i n a l l y , a d i s c u s s i o n
o f t h e a p p l i c a t i o n o f f o r c e d - c h o i c e t e c h n i q u e i n e x p e r i m e n
t a l a n d c l i n i c a l t h r e s h o l d m e a s u r e m e n t s w a s p r e s e n t e d .
L i n d q u i s t T y p e I d e s i g n w a s c h o s e n t o e x p l o r e t h e
68
69
p r o b l e m . E a c h o f t h e f o r t y s u b j e c t s w a s t e s t e d u t i l i z i n g
b o t h t h e f o r c e d - c h o i c e t e c h n i q u e a n d t h e y e s - n o t e c h n i q u e .
T h e f o r t y s u b j e c t s w e r e c h o s e n r a n d o m l y a f t e r a n i n i t i a l
b a t t e r y o f t e s t s i n d i c a t e d t h a t t h e y s a t i s f i e d t h e c r i t e r i a
f o r a c c e p t a b i l i t y . S p e e c h i n t e l l i g i b i l i t y t h r e s h o l d s a n d
s p e e c h d e t e c t i o n t h r e s h o l d s w e r e o b t a i n e d o n a l l s u b j e c t s
u s i n g t h e s t a n d a r d c l i n i c a l s e m a n t i c i n d i c a t o r . F o r c e d -
c h o i c e t h r e s h o l d s w e r e e s t a b l i s h e d u s i n g t h e a c c u r a c y i n d i
c a t o r .
A m i x e d a n a l y s i s o f v a r i a n c e w a s c o m p u t e d f o r t h e
e n t i r e p o p u l a t i o n t o d e t e r m i n e w h e t h e r s i g n i f i c a n t n o n c h a n c e
v a r i a t i o n s b e t w e e n m e a n s w a s p r e s e n t b e t w e e n t e s t s a n d b e
t w e e n g r o u p s . T h i s a n a l y s i s r e v e a l e d t h e m a i n e f f e c t o f
t e s t s t o b e s i g n i f i c a n t a n d t h e s e t h r e s h o l d d a t a w e r e
t r e a t e d s t a t i s t i c a l l y u s i n g t h e t . t e s t .
I n a d d i t i o n , P e a r s o n ' s or w a s a p p l i e d t o t h e v a r i o u s
t h r e s h o l d m e a s u r e m e n t s t o d e t e r m i n e r e l a t i o n s h i p s a m o n g t h e
t w o g r o u p s a n d a m o n g t h e c o m b i n e d p o p u l a t i o n . T h e s e c o r r e
l a t i o n s w e r e c o m p u t e d t o d e t e r m i n e t h e r e l a t i o n s h i p b e t w e e n
t h e s p e e c h m e a s u r e m e n t s . T h e r a t i o o f d i f f e r e n c e s b e t w e e n
j r ' s w a s o b t a i n e d f o r t h e c o r r e l a t i o n s s h o w i n g t h e l a r g e s t
d i f f e r e n c e b e t w e e n g r o u p s .
70
C o n c l u s i o n s
W i t h i n t h e l i m i t s o f t h i s e x p e r i m e n t , t h e f o l l o w i n g
c o n c l u s i o n s a p p e a r w a r r a n t e d :
1 . T h e f o r c e d - c h o i c e t e c h n i q u e s h o w e d l o w e r s p e e c h
i n t e l l i g i b i l i t y t h r e s h o l d s t h a n t h e Y e s - N o t e c h n i q u e f o r
b o t h g r o u p s , t h o s e w i t h c o n d u c t i v e h e a r i n g l o s s a n d t h o s e
w i t h s e n s o r i - n e u r a l h e a r i n g l o s s .
2 . T h e f o r c e d - c h o i c e t e c h n i q u e d e m o n s t r a t e d s e s
s i o n - t o - s e s s i o n r e l i a b i l i t y .
3 . S p e e c h d e t e c t i o n t h r e s h o l d s w e r e l o w e r t h a n
t h e f o r c e d - c h o i c e t h r e s h o l d s f o r a l l s u b j e c t s .
4 . N o d i f f e r e n c e s w e r e s h o w n b e t w e e n t h e h a r d o f
h e a r i n g s u b j e c t s i n e i t h e r g r o u p , c o n d u c t i v e o r s e n s o r i
n e u r a l , i n t h e u s e o f t h e t h r e e s p e e c h t e s t s .
I m p l i c a t i o n s
T h i s i n v e s t i g a t i o n h a s p r o d u c e d v a l u a b l e i n f o r m a
t i o n c o n c e r n i n g t h e c l i n i c a l a p p l i c a t i o n o f t h e f o r c e d -
c h o i c e i n d i c a t o r i n e s t a b l i s h i n g t h r e s h o l d s o f s p e e c h i n
t e l l i g i b i l i t y . A l l o f t h e r e s e a r c h p r e c e d i n g t h i s s t u d y
u s e d p u r e t o n e s a s t h e s t i m u l i a n d t h e s u b j e c t s w e r e a l l
n o r m a l h e a r i n g . T h i s w a s t h e f i r s t s t u d y t o b e c o m p l e t e d
u s i n g h a r d o f h e a r i n g s u b j e c t s , a n d t o u s e s p e e c h a s t h e
71
s t i m u l u s . T h e s p e e c h i n t e l l i g i b i l i t y t h r e s h o l d s u s i n g t h e
f o r c e d - c h o i c e i n d i c a t o r w e r e a c c u r a t e a n d r e l i a b l e e s t i m a t e s
o f a u d i t o r y a c u i t y . T h e f i n d i n g s s u g g e s t t h a t t h i s c l i n i c a l
a d a p t a t i o n o f t h e f o r c e d - c h o i c e t e c h n i q u e c a n b e u s e d f o r
e s t a b l i s h i n g a u d i o l o g i c a l t h r e s h o l d s f o r s p e e c h . B e c a u s e o f
t h e r e l i a b i l i t y f o u n d i n s e s s i o n - t o - s e s s i o n t e s t i n g i t i s
p r o p o s e d t h a t t h i s t e c h n i q u e w o u l d b e p a r t i c u l a r l y v a l u a b l e
i n m e d i c o - l e g a l a u d i o l o g i c a l e v a l u a t i o n s .
S e v e r a l p r o b l e m s w e r e e v i d e n t w i t h t h e p r o c e d u r e
u s i n g t h e f o r c e d - c h o i c e t e c h n i q u e . T h e n e e d t o u s e c a r d s
w i t h t h e l i s t s t y p e d o n t h e m m a d e i t m a n d a t o r y f o r t h e s u b
j e c t s t o h a v e a d e q u a t e v i s i o n a n d a n a b i l i t y t o r e a d a t t h e
f i f t h g r a d e l e v e l . I n a c t u a l c l i n i c a l a p p l i c a t i o n t h e s e
r e s t r i c t i o n s w o u l d c o n f i n e t h e u s e o f t h i s t e s t t o s u b j e c t s
m e e t i n g t h e v i s u a l a n d r e a d i n g r e q u i r e m e n t s . P i c t u r e s , h o w
e v e r , m i g h t e l i m i n a t e a n y r e a d i n g p r o b l e m s t h a t m i g h t b e
e n c o u n t e r e d i n t h e e x a m i n a t i o n o f c h i l d r e n . A p i c t u r e o f
a b a s e b a l l , t o o t h b r u s h , e t c . , w o u l d b e p l a c e d o n t h e c a r d s
i n s t e a d o f t h e p r i n t e d w o r d . A f o l l o w - u p e x p e r i m e n t o n
c h i l d r e n u s i n g t h i s t y p e o f c u e c a r d w o u l d p o s s i b l y p r o v e
f r u i t f u l i n e v a l u a t i n g t h e u s e f u l n e s s o f t h i s m e t h o d f o r
a l l t y p e s o f s u b j e c t s .
The use of this technique for establishing intelli
g i b i l i t y t h r e s l i o l d s o n p a t i e n t s w i t h n o n - o r g a n i c h e a r i n g
l o s s s h o u l d h e c o n s i d e r e d i n c l i n i c a l t e s t i n g . O n e s u b j e c t
w h o w a s r e f e r r e d w i t h c o n s i s t e n t r e s u l t s o n t h e p r e - t e s t
b a t t e r y s h o w e d m u c h b e t t e r f o r c e d - c h o i c e t h r e s h o l d s t h a n
c o u l d b e e x p l a i n e d b y t h e p u r e t o n e t h r e s h o l d s . A c o m p l e t e
r e - e x a m i n a t i o n w a s a c c o m p l i s h e d a n d f i n a l t h r e s h o l d s f o r
b o t h s p e e c h r e c e p t i o n a n d p u r e t o n e s r e v e a l e d t h a t t h e
f o r c e d - c h o i c e t h r e s h o l d s w e r e i n d i c a t i v e o f a c t u a l o r g a n i c
t h r e s h o l d s . A l t h o u g h t h e s u b j e c t h a d t o b e r e j e c t e d , r e
s u l t s s u g g e s t t h a t p a t i e n t s w h o s h o w a r e l u c t a n c e t o r e s p o n d
a t t h r e s h o l d o r w h o s e r e s p o n s e s i n d i c a t e a d e g r e e o f n o n -
o r g a n i c h e a r i n g l o s s s h o u l d b e e v a l u a t e d u s i n g t h i s f o r c e d -
c h o i c e t e c h n i q u e .
T h e f o r c e d - c h o i c e t e c h n i q u e d o e s n o t c o n t r o l f a l s e
n e g a t i v e r e s p o n s e s g i v e n i n t e n t i o n a l l y b y t h e s u b j e c t s .
T h e n e e d f o r a t e s t d e s i g n t o d e t e c t t h e s e r e s p o n s e s i s i n
d i c a t e d . U n t i l t h i s t y p e o f r e s p o n s e i s c o n t r o l l e d o t h e r
a u d i o l o g i c a l t e s t s w o u l d h a v e t o b e i m p l e m e n t e d i f t h e s u b
j e c t w e r e f e i g n i n g a t o t a l l o s s o f h e a r i n g .
T h e u t i l i z a t i o n o f t h e f o r c e d - c h o i c e t e c h n i q u e i n
f u t u r e r e s e a r c h c o m p a r i n g s p e e c h d e t e c t i o n t h r e s h o l d s o b
t a i n e d u s i n g t h e a c c u r a c y i n d i c a t o r w i t h t h o s e o b t a i n e d u s
i n g t h e s e m a n t i c i n d i c a t o r s h o u l d a l s o p r o v e f r u i t f u l .
a p p e n d i x e s
APPENDIX A
E X P E R I M E N T E R ' S M A T E R I A L S
F O R C E D - C H O I C E W O R K S H E E T
N A M E
C # _
T Y P E O F L O S S
L E V E L
P / T A V .
A G E _
E A R
S E X
O R D E R
W O R D
L E V E L
W O R D
1 . w o r k s h o p
1 7 .
s i d e w a l k
2 . s c a r e c r o w
1 8 .
b l a c k b o a r d
3 . d o o r s t e p
1 9 .
b o n b o n
4 . w i l d c a t
20 . d o o r m a t
5 . f i r e f l y
21 .
b l o o d h o u n d
6 .
t h e r e f o r e
22 . a r m c h a i r
7 .
n o r t h w e s t
2 3 . v a m p i r e
8 . d o v e t a i l
2 4 .
w a s h b o a r d
9 . a i r p l a n e
2 5 .
h e a d l i g h t
10 .
t o o t h b r u s h
2 6 . c a r g o
11 . m u s h r o o m
2 7 . h o t d o g
12 . d r a w b r i d g e
2 8 . p a n c a k e
1 3 .
b o b w h i t e
2 9 . n u t m e g
1 4 . w h i z z b a n g
3 0 . e y e b r o w
1 5 . p a n c a k e
3 1 . p a d l o c k
1 6 .
p a d l o c k
3 2 . b a g p i p e
S D T T h r e s h
F C T h r e s h :
3 3 . w o o d c h u c k
34 . w o r k s h o p
35 . b i r t h d a y
3 6 . n o r t h w e s t
76
3 7 . h o r s e s h o e
3 8 . h o t d o g
__________ 3 9 . l i f e b o a t
4 0 . ' v a m p i r e
SIT Thresh:______________
# 2 F C T h r e s h : ________________________
BINOMIAL EXPANSION FOR FIVE-WORD LISTS
# T R I A L S # C O R R E C T P R O B A B I L I T Y
1 0 . 8 0 0
1 1 . 2 0 0
2 0 . 6 4 0
2 1 . 3 2 0
2 2 . 0 4 0 *
3 0 . 5 1 2
3 1 . 3 8 4
3 2 . 0 9 6
3 3 . 0 0 8 *
4 0 . 4 1 0
4 1 . 4 1 0
4 2 . 1 5 4
4 3 . 0 2 6 *
5 3 . 0 5 1
5 4 . 0 0 6 *
* U s i n g f o u r t r i a l s a t e a c h l e v e l , t h e e x p e r i m e n t e r
c o u l d d r a w t h e c o n c l u s i o n t h a t t h e s u b j e c t d i d b e t t e r - t h a n
c h a n c e ( a t t h e 5 p e r c e n t l e v e l o f c o n f i d e n c e ) i f h e c o r
r e c t l y a n s w e r e d t w o o u t o f t w o , t h r e e o u t o f t h r e e , o r
t h r e e o u t o f f o u r w o r d s .
77
. A P P E N D I X B
T A P E D M A T E R I A L
!
ORDER OF TAPED P.A.L. AUDITORY TEST #9 (Spondee)
b l o o d h o u n d t o o t h b r u s h
i n k w e l l b a g p i p e
s h o t g u n w o o d w o r k
e g g p l e n t e a r t h q u a k e
n o r t h w e s t b i r t h d a y
r a i l r o a d p l a y g r o u n d
h o r s e s h o e v a m p i r e
s i d e w a l k m o u s e t r a p
a l t h o u g h g r e y h o u n d
p i n b a l l h e a d l i g h t
c u p c a k e a i r p l a n e
b l a c k b o a r d c a r g o
w i g w a m f i r e f l y
l i f e b o a t g r a n d s o n
b e e h i v e s h i p w r e c k
m i s h a p o u t l a w
w o o d c h u c k b l a c k o u t
o u t s i d e w h i t e w a s h
f o o t s t o o l e a r d r u m
w i l d c a t h o t h o u s e
c o o k b o o k b u c k w h e a t
e y e b r o w y a r d s t i c k
s c h o o l b o y w a s h b o a r d
b a c k b o n e p l a y m a t e
p a d l o c k d a y b r e a k
t h e r e f o r e h o u s e w o r k
s o y b e a n n u t m e g
w h i z z b a n g d o o r s t e p
i c e b e r g w o r k s h o p
s u n d o w n j a c k k n i f e
a r m c h a i r w a t c h w o r d
b o n b o n d o o r m a t
c o u g h d r o p h e d g e h o g
s u n s e t p a n c a k e
f a r e w e l l s t a r l i g h t
h a r d w a r e m u s h r o o m
79
d u c k p o n d
p l a t f o r m
b o b w h i t e
s t a i r w a y
o a t m e a l
hot dog
b a s e b a l l
d r a w b r i d g e
dovetail
c o w b o y
m i d w a y
scarecrow
ORDER OF FORCED-CHOICE TEST WORDS AND COMMANDS
List
L i s t
List
i) l i s t e n :
Workshop
g u e s s :
11) listen:
Mushroom
guess:
2 ) l i s t e n :
Scarecrow
G U E S S :
L i s t # 1 2 ) L I S T E N :
D r a w b r i d g e
g u e s s :
f* 3 ) l i s t e n :
D o o r s t e p
g u e s s :
1 3 ) l i s t e n :
B o b w h i t e
g u e s s :
4) l i s t e n :
Wildcat
g u e s s :
14) listen:
Whizzbang
g u e s s :
5 ) l i s t e n :
Firefly
g u e s s :
L i s t # 1 5 ) L I S T E N :
P a n c a k e
g u e s s :
w 6 ) l i s t e n :
T h e r e f o r e
g u e s s :
1 6 ) l i s t e n :
P a d l o c k
g u e s s :
7 ) l i s t e n :
N o r t h w e s t
g u e s s :
17 ) l i s t e n :
S i d e w a l k
G U E S S :
8 ) l i s t e n :
D o v e t a i l
g u e s s :
L i s t # 1 8 ) L I S T E N :
B l a c k b o a r d
g u e s s :
# 9 ) l i s t e n :
A i r p l a n e
g u e s s :
19 ) l i s t e n :
B o n b o n
g u e s s :
io) l i s t e n :
T o o t h b r u s h
g u e s s : 81
2 0 ) l i s t e n :
D o o r m a t
g u e s s :
82
L i s t # 2 1 ) L I S T E N !
B l o o d h o u n d
G U E S S !
L i s t # 32 ) l i s t e n :
B a g p i p e
g u e s s :
2 2 ) l i s t e n :
A r m c h a i r
g u e s s :
3 3 ) l i s t e n :
W o o d c h u c k
g u e s s :
2 3 ) l i s t e n :
V a m p i r e
g u e s s :
3 4 ) l i s t e n :
W o r k s h o p
g u e s s :
2 4 ) l i s t e n :
W a s h b o a r d
g u e s s :
L i s t # 3 5 ) L I S T E N :
B i r t h d a y
g u e s s :
L i s t # 2 5 ) L I S T E N :
H e a d l i g h t
G U E S S :
3 6 ) l i s t e n :
N o r t h w e s t
g u e s s :
2 6 ) l i s t e n :
C a r g o
g u e s s :
3 7 ) l i s t e n :
H o r s e s h o e
g u e s s :
2 7 ) l i s t e n :
H o t d o g
g u e s s :
L i s t # 3 8 ) L I S T E N :
H o t d o g
g u e s s :
2 8 ) l i s t e n :
p a n c a k e
g u e s s :
3 9 ) L I S T E N :
L i f e b o a t
g u e s s :
L i s t # 2 9 ) L I S T E N :
N u t m e g
g u e s s :
4 0 ) l i s t e n :
V a m p i r e
g u e s s :
30 ) l i s t e n :
E y e b r o w
g u e s s :
3 1 ) l i s t e n :
P a d l o c k
g u e s s :
A P P E N D I X C
S U B J E C T M A T E R I A L S
*
A U D I T O R Y T E S T P . A . L . # 9
LIST I AND II
a i r p l a n e d o o r s t e p i n k w e l l s h i p w r e c k
a l t h o u g h d o v e t a i l j a c k k n i f e s h o t g u n
a r m c h a i r d r a w b r i d g e 1 i f e b o a t s i d e w a l k
b a c k b o n e d u c k p o n d m i d w a y s o y b e a n
b a g p i p e e a r d r u m m i s h a p s t a i r w a y
b a s e b a l l
e a r t h q u a k e m o u s e t r a p s t a r 1 i g h t
b e e h i v e e g g p l a n t m u s h r o o m s u n d o w n
b i r t h d a y e y e b r o w n o r t h w e s t s u n s e t
b l a c k b o a r d f a r e w e l l n u t m e g t h e r e f o r e
b l a c k o u t f i r e f l y o a t m e a l t o o t h b r u s h
b l o o d h o u n d f o o t s t o o l o u t l a w v a m p i r e
b o b w h i t e g r a n d s o n o u t s i d e w a s h b o a r d
b o n b o n g r e y h o u n d p a d l o c k w a t c h w o r d
b u c k w h e a t h a r d w a r e p a n c a k e w h i t e w a s h
c a r g o h e a d l i g h t p i n b a l l w h i z z b a n g
c o o k b o o k h e d g e h o g p l a t f o r m w i g w a m
c o u g h d r o p h o r s e s h o e p l a y g r o u n d w i l d c a t
c o w b o y h o t d o g p l a y m a t e w o o d c h u c k
64
cupcake
daybreak
door mat
h o t h o u s e
housework
iceberg
r a i l r o a d
s c a r e c r o w
schoolboy
w o o d w o r k
w o r k s h o p
yardstick
0
F O R C E D - C H O I C E W O R D L I S T S
A D A P T E D F R O M P . A . L . # 9
L i s t 1 L i s t 5 L i s t 9
1 .
w o r k s h o p
1 . d a y b r e a k 1 . h a r d w a r e
2 . b l a c k o u t
2 . a l t h o u g h 2 .
d a y b r e a k
3 . m i d w a y
3 . w o o d w o r k
3 .
b l a c k o u t
4 . h o r s e s h o e
4 . f i r e f l y 4 .
a i r p l a n e
5 . b u c k w h e a t
5 . b o b w h i t e
5 .
m u s h r o o m
L i s t 2
L i s t 6 L i s t 1 0
1 .
p l a y g r o u n d
1 . y a r d s t i c k
1 .
r a i l r o a d
2 . s c a r e c r o w
2 . o u t s i d e 2 . w i g w a m
3 . h o t d o g
3 . h o r s e s h o e
3 .
t o o t h b r u s h
4 . p l a t f o r m
4 . e g g p l a n t
4 .
s c a r e c r o w
5 . n u t m e g
5 . t h e r e f o r e
5 .
b l a c k b o a r d
L i s t 3
L i s t 7 L i s t 1 1
1 . d a y b r e a k
1 .
n o r t h w e s t
1 .
b a c k b o n e
2 . d o o r s t e p
2 . p a d l o c k 2 . w i g w a m
3 . w a s h b o a r d
3 . s t a r l i g h t
3 .
a r m c h a i r
4 . m u s h r o o m
4 . l i f e b o a t
4 . m u s h r o o m
5 . v a m p i r e
5 . s h i p w r e c k
5 . c o w b o y
L i s t 4
L i s t 8 L i s t 1 2
1 .
s t a i r w a y
1 .
b a s e b a l l 1 .
d r a w b r i d g e
2 . s i d e w a l K
2 . b l o o d h o u n d 2 . p a n c a k e
3 . c o w b o y
3 . d o v e t a i l - 3 .
c o u g h d r o p
4 . c o o k b o o k
4 . m o u s e t r a p 4 . g r e y h o u n d
5 . w i l d c a t
5 . p i n b a l l 5 -
o u t l a w
86
87
L i s t 1 3 L i s t 1 8
L i s t 2 3
1 . h e a d l i g h t
1 . c a r g o 1 . i c e b e r g
2 . o a t m e a l
2 . b l a c k b o a r d 2 . v a m p i r e
3 . f i r e f l y
3 . c o u g h d r o p 3 . m o u s e t r a p
4 . b o b w h i t e
4 . w o r k s h o p 4 . w i g w a m
5 . g r a n d s o n
5 . g r a n d s o n 5 . e a r t h q u a k e
L i s t 1 4
L i s t 1 9 L i s t 2 4
1 .
w h i z z b a n g
1 . b l a c k o u t 1 . w a s h b o a r d
2 . b a g p i p e
2 . w h i z z b a n g 2 . t o o t h b r u s h
3 . m i d w a y
3 . b o n b o n 3 . b o n b o n
4 . w i l d c a t
4 . h e d g e h o g 4 . b l a c k o u t
5 . s u n d o w n
« »
5 . e a r t h q u a k e 5 . p l a t f o r m
L i s t 1 5 L i s t 2 0 L i s t 2 5
1 . b o n b o n
1 . b a s e b a l l
1 .
s h i p w r e c k
2 . h e d g e h o g
2 . p i n b a l l 2 . p l a y g r o u n d
3 . e g g p l a n t
3 . m u s h r o o m 3 . p l a y m a t e
4 . w a t c h w o r d
4 . d o o r m a t 4 . m u s h r o o m
5 . p a n c a k e
5 . b u c k w h e a t 5 . h e a d l i g h t
L i s t 1 6
L i s t 2 1 L i s t 2 6
1 . p i n b a l l
1 . b o n b o n 1 . w o r k s h o p
2. p a d l o c k
2 . b l o o d h o u n d
2 . c a r g o
3 . i n k w e l l
3 . w o o d w o r k 3 . t h e r e f o r e
4 . e a r d r u m
4 . b a g p i p e 4 . s u n d o w n
5 . r a i l r o a d
5 . s h i p w r e c k 5 . n o r t h w e s t
L i s t 1 7 L i s t 2 2 L i s t 2 7
1 . b a c k b o n e
1 . h e d g e h o g
1 . d o o r m a t
2 . o u t s i d e
2 . c o u g h d r o p 2 . h o t d o g
3 . n o r t h w e s t
3 . c a r g o
3 . n u t m e g
4 . s i d e w a l k
4 . m u s h r o o m 4 . i c e b e r g
5 . l i f e b o a t
5 . a r m c h a i r 5 . b e e h i v e
88
L i s t 2 8 L i s t 3 3 L i s t 3 8
1 .
d a y b r e a k 1 .
p l a y m a t e
1 . h o t d o g
2 . b u c k w h e a t 2 . p l a y g r o u n d 2 . p a n c a k e
3 . p a n c a k e 3 . w o o d c h u c k 3 . o u t l a w
4 . s t a i r w a y 4 . b l a c k o u t 4 . w i g w a m
5 . p l a y g r o u n d 5 . s u n d o w n 5 . b i r t h d a y
L i s t 2 9 L i s t 3 4 L i s t 3 9
1 .
s h i p w r e c k
1 .
c o o k b o o k
1 . d o o r m a t
2 . h e d g e h o g 2 . b l o o d h o u n d 2 . p l a t f o r m
3 . n u t m e g
3. d o o r m a t 3 . e g g p l a n t
4 . a i r p l a n e 4 . v a m p i r e 4 . w h i t e w a s h
5 . b a s e b a l l 5 . w o r k s h o p . 5 . l i f e b o a t
L i s t 3 0 L i s t 3 5 L i s t 4 0
1 . e y e b r o w
1 .
c u p c a k e
1 . d o v e t a i l
2 . m u s h r o o m 2 . c o w b o y 2 . f a r e w e l l
3. s u n s e t
3. c o u g h d r o p 3. b a c k b o n e
4 . p i n b a l l 4 . b i r t h d a y 4 . v a m p i r e
5 . r a i l r o a d 5 . d o o r s t e p 5 . s t a r l i g h t
L i s t 3 1 L i s t 3 6
1 . g r e y h o u n d 1 . h a r d w a r e
2 . w o o d c h u c k 2 . s c a r e c r o w
3 . p a d l o c k 3 . n o r t h w e s t
4 . e a r t h q u a k e 4 . t h e r e f o r e
5 . h e a d l i g h t 5 . c a r g o
L i s t 3 2 L i s t 3 7
1 .
e y e b r o w
1 . g r a n d s o n
2 . b a g p i p e 2. w a s h b o a r d
3 . y a r d s t i c k 3 . b o n b o n
4 . d u c k p o n d 4 . m i s h a p
5 . p a n c a k e 5 . h o r s e s h o e
G R A Y ' S O R A L R E A D I N G T E S T
O n e o f t h e m o s t i n t e r e s t i n g b i r d s w h i c h e v e r l i v e d
i n m y b i r d r o o m w a s a b l u e j a y n a m e d J a c k i e . H e w a s f u l l o f
b u s i n e s s f r o m m o r n i n g t i l l n i g h t , s c a r c e l y e v e r s t i l l . H e
b a d b e e n s t o l e n f r o m a n e s t l o n g b e f o r e b e c o u l d f l y , a n d
b e b a d b e e n r e a r e d i n a b o u s e l o n g b e f o r e h e b a d b e e n g i v e n
t o m e a s a p e t .
89
APPENDIX D
I N S T R U C T I O N S F O R :
a ) B e k e s y A u d i o m e t r y
b ) S p e e c h I n t e l l i g i b i l i t y T h r e s h o l d M e a s u r e m e n t
c ) F o r c e d - C h o i c e T h r e s h o l d M e a s u r e m e n t
d ) S p e e c h D e t e c t i o n T h r e s h o l d M e a s u r e m e n t
INSTRUCTIONS FOR BEKESY AUDIOMETRY
Y o u w i l l b e t e s t e d t w i c e w i t h t h i s a u t o m a t i c a u d i o
m e t e r . T h e f i r s t t e s t w i l l c o n s i s t o f a p u l s e d t o n e ( b e e p -
b e e p - b e e p ) . W h e n e v e r y o u a r e s u r e y o u h e a r t h i s p u l s e d
t o n e p r e s s t h e l e v e r . K e e p i t d o w n a s l o n g a s y o u h e a r t h e
p u l s e d t o n e a n d r e l e a s e i t w h e n y o u n o l o n g e r h e a r i t .
T h e s e c o n d t e s t w i l l c o n s i s t o f a c o n t i n u o u s t o n e
( b e e e e e e e e p ) . F o l l o w t h e s a m e p r o c e d u r e b y d e p r e s s i n g t h e
l e v e r a s l o n g a s y o u h e a r t h e t o n e a n d r e l e a s i n g i t w h e n
y o u n o l o n g e r h e a r i t .
I N S T R U C T I O N S F O R S I T
H e r e i s a l i s t o f w o r d s w h i c h I w i l l g i v e y o u d u r
i n g t h e t e s t . P l e a s e s t u d y t h e s e w o r d s f o r t h e n e x t f i v e
m i n u t e s s o t h a t y o u w i l l b e c o m e f a m i l i a r w i t h t h e m .
N o w w e w i l l b e g i n t h e t e s t . I w i l l g i v e y o u t h e s e
t w o - s y l l a b l e w o r d s . J u s t a s s o o n a s y o u h e a r t h e m , r e p e a t
t h e m b a c k t o m e . I f y o u h e a r 11 c o w b o y , " r e p e a t a l o u d " c o w
b o y . " T h e s e w o r d s w i l l b e v e r y s o f t . Y o u w i l l h a v e t o
91
92
s t r a i n t o h e a r t h e m , b u t j u s t a s s o o n a s y o u c a n m a k e t h e m
o u t , r e p e a t t h e m . D o y o u h a v e a n y q u e s t i o n s ?
I N S T R U C T I O N S F O R F C T E S T
T h e r e a r e f i v e w o r d s l i s t e d o n e a c h c a r d . A t t h e
t o p o f e a c h c a r d t h e n u m b e r o f t h e c a r d i s i n d i c a t e d . B e -
f o r e e a c h t e s t w o r d i s g i v e n , y o u w i l l h e a r a m a n ' s v o i c e
s a y i n g " L i s t e n l " T h i s i s y o u r s i g n a l t o b e a t t e n t i v e a s
t h e t e s t w o r d w i l l s o o n f o l l o w . F o l l o w i n g t h e t e s t w o r d
y o u w i l l h e a r t h e c o m m a n d " G u e s s I " U p o n t h i s c o m m a n d s e
l e c t t h e w o r d t h a t y o u t h i n k w a s g i v e n a n d r e p e a t i t a l o u d .
Y o u m u s t g u e s s a f t e r e a c h c o m m a n d w h e t h e r y o u w e r e a w a r e
t h a t y o u h e a r d a w o r d o r n o t . A f t e r s e l e c t i n g a w o r d f r o m
t h e l i s t , r o t a t e t h e c a r d t o t h e b a c k . Y o u a r e t h e n r e a d y
f o r t h e n e x t t e s t s e r i e s . A t c e r t a i n i n t e r v a l s t h e l i s t
n u m b e r w i l l b e g i v e n t o m a k e s u r e y o u h a v e r o t a t e d t h e c a r d
t o t h e c o r r e c t l i s t . I f y o u f i n d a d i s c r e p a n c y , n o t i f y t h e
e x a m i n e r i m m e d i a t e l y . R e m e m b e r , y o u m u s t r e s p o n d w i t h a
s e l e c t e d w o r d a f t e r t h e c o m m a n d " G u e s s ! "
I N S T R U C T I O N S F O R S P E E C H D E T E C T I O N
T H R E S H O L D T E S T
T h i s t e s t w i l l u t i l i z e t w o - s y l l a b l e w o r d s . J u s t a s ^
93
s o o n a s y o u t h i n k y o u h e a r s o m e t h i n g , r a i s e y o u r f i n g e r .
K e e p i t u p a s l o n g a s y o u h e a r s o m e t h i n g a n d l o w e r i t w h e n
*
y o u c a n n o l o n g e r h e a r a n y t h i n g . D o n o t w a i t u n t i l y o u c a n
u n d e r s t a n d t h e w o r d s . R a i s e y o u r f i n g e r w h e n y o u t h i n k y o u
c a n d e t e c t a n o i s e a n d l o w e r i t w h e n y o u c a n n o l o n g e r d e
t e c t i t .
A P P E N D I X E
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BIBLIOGRAPHY
BIBLIOGRAPHY
Books
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1-5*
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"The Relationship of Subliminal Perception to
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10.0
Hirsh, Ira, et al. "Development of Materials for Speech
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Hughson, W. and Westlake, H. "Manual for Program Outline
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Wilcott, R. C. "A Search for Subthreshold Conditioning at
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Experimental Psychology. XLVI (October, 1953), 271-
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Unpublished Materials
Smith, Bettye W. "An Experimental Study to Determine Speech
Intelligibility Thresholds Using Forced-Choice Tech
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Tests
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*

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Asset Metadata

Creator Smith, Bettye Wilton (author)

Core Title An Experimental Study Of Intelligibility Thresholds Of Hypacusic Adults Using Forced-Choice And Yes-No Techniques

Degree Doctor of Philosophy

Degree Program Speech

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag OAI-PMH Harvest,Theater

Language English

Contributor Digitized by ProQuest (provenance)

Advisor Garwood, Victor P. (committee chair), Boyd, Harold M.E. (committee member), Dickens, Milton (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c18-317834

Unique identifier UC11359058

Identifier 6405164.pdf (filename),usctheses-c18-317834 (legacy record id)

Legacy Identifier 6405164.pdf

Dmrecord 317834

Document Type Dissertation

Rights Smith, Bettye Wilton

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

Repository Name University of Southern California Digital Library

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