assessment of hearing handicap: comment on the ’’kryter series’’

Assessment of hearing handicap: comment on the "Kryter series"

William G. Noble

University of New England, Armidale, Australia (Received 14 August 1974; revised 4 November 1974)

The assessment of hearing handicap resulting from exposure to noise has been extensively discussed by Kryter [J. Acoust. Soc. Am. 53, 1211-1234 (1973)] and by subsequent commentators. It is argued that many problems and relevant findings on this issue have been overlooked in that series. It is further argued that a measure based on self-report holds more promise for the valid assessment of hearing handicap resulting from noise-induced hearing loss than performance tests of auditory pure-tone sensitivity or speech reception.

Subject Classification: 65.64; 50.70.

I suppose gaining the publication of one's researches is the first battle; the next is to get people to take notice of them once published. In an early paper (Noble, 1968) I presented findings of research on groups of men exposed to different amounts of occupational noise, and showed that the assessment of hearing handicap was possible using a self-report technique. The use of self-report was not itself new. Silverman, Thurlow, Walsh, and Davis (1948) and High, Fairbanks, and Glorig (1964) used self-report methods, the latter group even made efforts to secure the reliability of their scale. My research, however, was the first to be carried out in the very population for whom handicap assessment is of such vital interest. Had that (minor) work been my only contribution to this problem area I would not have ex- perienced the frustration which resulted from reading the paper by Kryter (1973) on the topic of "Impairment to hearing from exposure to noise" and from some of the responses to that paper. But the fact is that since the time of that initial work, one minor (Noble, 1970)and two major reports (Noble and Atherley, 1970; Atherley and Noble, 1971) have appeared, all of which were avail- able prior to receipt of the "Kryter series" by this journal.

I would like to use this opportunity to outline relevant aspects of the work referred to above (plus related studies) in the hope that some of the apparent obscurity (and conversely, some of the apparent certitude)which is expressed in the Kryter series concerning the measurement of hearing handicap and the role of performance tests in that endearour can be reviewed.

In the first work referred to (Noble, 1968), the results showed that average self-reported impairment of everyday hearing ability on a short questionnaire was dis- tributed significantly across otherwise matched occupational groups exposed habitually to different amounts of noiseø A direct relation, then, was observable between causal agent and resulting handicap. While the latter was also directly related to average pure-tone threshold sensitivity of the groups, no attempt was made at that time to correlate the two measures.

In considering the question of criterion of hearing handicap, the point was put then, and in a later work (Noble, 1970), that arbitrary "fences" were of unknown validity in making what is, after all, a social decision.

A behavioral criterion promised greater validity. The criterion proposed was the lowest questionnaire score obtainable in samples of people drawn from hearing clinics. This population can reliably be considered as hearing handicapped, for it comprises people who have come seeking help for disorders which are no longer tolerable in their day-to-day lives. Thus, anyone in a "noise-induced-hearing-loss" population whose questionnaire score lies above the lowest hearing clinic score can be considered to suffer "everyday hearing handicap." In an unpublished work (Noble, 1969), the above notion was presented in a more refined form. The tenth-percentile score from the hearing clinic population was proposed as the "fence, to ensure that the criterion excluded persons who (it was observed) were coerced into attending the clinic, and also persons whose sole complaint was tinnitus (a disabling phenomenon in its own right, as I will point out later, but for criterion purposes irrelevant to the issue)ø Further, the distribution of questionnaire scores observed in hearing clinic samples could stand as the incremental distribution of "hearing handicap," such that an individual whose score lay at the 50th percentlie of the clinic sample distribution would be 50% handicapped, and so on. [

The above criterion was uttered in connection with

a more advanced questionnaire. This, the Hearing Measurement Scale (HMS) has been fully and publicly described (Noble and Atherley, 1970), and in answer to the question which may be already forming in the reader's mind, this scale has been thoroughly tested and is of proven reliability. Repeated application on 27 industrial subjects after six months gave a reliability coefficient (Spearman) of 0.928. The validity of the HMS for assessing everyday hearing handicap has also been secured by virtue of extensive research in clinical and industrial groups to obtain questions which are relevant and relevantly weighted to the effects of deafness in daily life. It is, to date, the only instrument whose development has been throughout handled with due consideration to principles of test construction, for the purpose in developing it was to obtain a valid system for measuring degree of hearing handicap per se, and not a list of questions whose nature conformed to the sort of auditory function measured by pure-tone or speech tests.

750 J. Acoust. Soc. Am., Vol. 57, No. 3, March 1975 Copyright ¸ 1975 by the Acoustical Society of America 750

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751 Letters to the Editor 751

In his summing-up of the symposium at which further data regarding the Hearing Measurement Scale were presented (Atherley and Noble, 1971), Glorig (1971) stated: "lVhen the questionnaire appears to come out with different results than one would expect from look- ing at the man's hearing levels, there is probably some- thing wrong with the questionnaire" (p. 258). This opinion reflects the style of the Hearing Handicap Scale (High, Fairbanks, and Glorig, 1964), which Speaks, Jerger, and Trammell (1970) foun•d to be a measure of auditory detection (i.e., a verbal equivalent of threshold determination--what Glorig would call "hearing level").

Not, one should emphasize, that performance tests are to be regarded with outright suspicion. But they cannot be seriously accepted a l•riori as valid for measuring hearing handicap (q.v., Silverman and Hirsh, 1955). To be sure, part of the final validation of the Hearing Mea- surementscale wasa comparison of relevant subsections with appropriate performance measures--and confirma- tion of relations was gained between, e.g., speech detection and normal-condition everyday speech hearing; tonal threshold sensitivity and everyday signal detection. Also, as I will describe presently, correlations between the HMS as a whole and certain hearing tests are positive. But from the outset of the development program nothing was taken as valid for handicap assessment. Hearing handicap was seen, in any case, as involving more than failure to detect sounds, or even failure to aurally discriminate speech, although these are of major importance in the repertoire of auditory skills. Acquired disorder, such as tinnitus, was found to con- tribute significantly to hearing handicap in some in- stances, by reason of its interference with peaceful episodes and even with sleep. Disruption of spatial localization was also observed and made contribution

to overall handicap.

The reception of speech, in the final event, might be taken as the most critical role of the auditory system. But the requirements for "speech perception," as against "aural reception of speech" (the distinction be- ing one between everyday and clinical test contexts) are quite different. Visual discrimination, to aid in pickup of lip and laryngeal movement (Sanders and Goodrich, 1971), and localization ability, to aid in pickup of signals in a competitive surround (Broadbent, 1958), play their part in the everyday world. And use of such a skill as lip-reading is mediated by the factor of visual acuity (Hardick, Oyer, and Irion, 1970), and even by the factor of job type. Kryter (1973) notes that Kell, Pearson, Acton, and Taylor (1971) found 53% of jute weavers reported reliance on lip-reading. I have reported elsewhere (Noble, 1972) that this high incidence is likely due to the fact of continuous occupational noise, making aural reception of speech impossible. In occupations where noise is intermittent, but just as damaging, lip-reading skill is not required, and therefore less likely to be acquired. •' So, final everyday handicap is the greater.

There is, as far as I can judge, no way that these kinds of intervening and extrinsic variables will be accounted for by a test of speech reception. How the

individual fares in the day-to-day world is presently assessable only by direct inquiry or observation. The latter is practically impossible, the former is quite possible, and, as I point out, at least one proven scale exists to provide means for doing the job.

It should be made clear that positive correlations are observable between scores on the HMS and tests of

auditory performance. Noble (1969)found that total- scale scores of a group of industrial subjects correlated best with speech reception threshold for continuous dis- course (a newspaper article) in a free-field test situa- tion IN= 30; Spearman (St)= 0. 632] and also correlated at St=0.565 with right-ear discrimination score for CID monosyllables (N=46). Correlation with pure-tone threshold, however, was virtually nonexistent at 0.5, 1, and 2 kHz (N=45), but reached levels of St=0.50 to 0.60 at 3, 4, and 6kHz.

These different levels of association show that lower-

frequency pure-tone sensitivity is unrelated to self- re- ported hearing handicap, and that while association between tests of speech hearing and self-report is evi- dent, it is not close enough for confident prediction in individual cases.

The above data and arguments should give "distin- guished researchers" in this field reason to reconsider what has to be assessed under the "hearing handicap" rubric. Futhermore, revision of traditional views is surely necessary in light of an extensive research of .the literature (Noble, 1973)whose outcome fails to support a conclusion that in those with noise-induced hearing loss there are reliable relations between tonal acuity and speech discrimination or even speech detection. I will wholeheartedly support Kryter and assert on the basis of correlational findings reported here and on the basis of the above-mentioned review that the use

of tonal threshold at 500 to 2000 Hz to predict anything other than signal detection ability is groundless.

Not only, then, is current practice failing to get to grips with the realities of everyday hearing handicap, it is not even internally consistent. The method I have developed has its own problems, particularly in regard to veracity of response, though that problem is not be- yond solution or control (Noble and Atherley, 1970). Its virtue lies in dealing squarely with the reality of the hearing handicap issue and in answering questions which, from the reading of your series, might be taken as not having been tackled.

1A preliminary application of this system was made to a group of 12 weavers, and it was found that three of them exceeded the criterion. Two of these, it turned out, had recently at- tended a hearing clinic to acquire hearing aids. A third weaver had also acquired a hearing aid, and her score lay just below the 10th percentlie. This is an eloquent, ff preliminary, finding in support of the validity of the proposal;

2All of the 12 weavers referred to earlier reported ability to lip-read; only 25% of fettlers, whose jobs entail intermittent exposure to noise, when they themselves work on a metal casting, reported likewise.

Atherley, G. R. C., and Noble, W. G. (1971). "Clinical Picture of Occupational Hearing Loss obtained with the Hear-

J. Acoust. Soc. Am., Vol. 57, No. 3, March 1975


752 Letters to the Editor 752

ing Measurement Scale," in Occupational Hearing Loss, D. W. Robinson, Ed. (Academic, London), pp. 193-206.

Broadbent, D. E. (1958). Perception and Communication (Pergamon, London), p. 25.

Glorig, A. (1971). "A Summing-up," in Occupational Hearing Loss, D. W. Robinson, Ed. (Academic, London), pp. 253-260.

Hardick, E. J., Oyer, H. J., and Irion, P. E. (1970). "Lip- reading Performance as Related to Measurements of Vision," J. Speech Hear. Res. 13, 92-100.

High, W. S., Fairbanks, G., and Glorig, A. (1964). "Scale for Self-Assessment of Hearing Handicap," J. Speech Hear. Disord. 29, 215-230.

Kell, R. L., Pearson, J. C. G., Acton, W. I., and Taylor, W. (1971). "Social Effects of Hearing Loss due to Weaving Noise," in Occupational Hearing Loss, D. W. Robinson, Ed. (Academic, London), pp. 179-191.

Kryter, K. D. (1973). "Impairment to Hearing from Exposure to Noise," J. Acoust. Soc. Am. 53, 1211-1234.

Noble, W. G. (1968), "The Assessment of Disability from Chronic Acoustic Trauma," Int. Audiol. 7, 353-359.

Noble, W. G. (1969). "A Scale for the Measurement of Hear- ing Loss and Disability," Doctoral dissertation, University of Manchester.

Noble, W. G. (1970). "A New Concept of Damage Risk Crite- rion," Ann. Occup. Hyg. 13, 69-75.

Noble, W. G. (1972). "Critical Factors in the Assessment of Deafness due to Noise," Malco Audiol. Lib. Ser. 11, (8).

Noble, W. G. (1973). "Pure-Tone Acuity, Speech-Hearing Ability and Deafness in Acoustic Trauma: A Review of the Literature," Audiol. 12, 291-315.

Noble, W. G., and Atherley, G. R. C. (1970). "The Hearing Measurement Scale: A Questionnaire for the Assessment of Auditory Disability," J. Aud. Res. 10, 229-250.

Sanders, D. A., and Goodrich, S. J. (1971). "The Relative Contributions of Visual and Auditory Components of Speech to Speech Intelligibility as a Function of Three Conditions of Frequency Distortion," J. Speech Hear. Res. 14, 154-159.

Silverman, S. R., Thur!ow, W. R., Walsh, T. E., and Davis, H. (1948). "Improvement in the Social Adequacy of Hearing following the Fenestration operation," Laryngoscope 58, 607-631.

Silverman, S. R., and Hirsh, I. J. (1955). "Problems Re- lated to the use of Speech in Clinical Audiometry," Ann. Otol. Rhinol. Laryngol. 64, 1234-1244.

Speaks, C., Jerger, J., and Trammell, T. (1970). "Measure- ment of Hearing Handicap," J. Speech Hear. Res. 13, 768- 776.

J. Acoust. Soc. Am., Vol. 57, No. 3, March 1975


assessment of hearing handicap: comment on the ’’kryter series’’

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