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Hearing Loss: Determining Eligibility for Social Security Benefits (2005)

Chapter: 4 Testing Adult Hearing: Conclusions and Recommendations

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Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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4
Testing Adult Hearing: Conclusions and Recommendations

KEY ISSUES

The committee was charged to answer several questions, which are addressed here as they pertain to adults. A few of these questions, dealing with nonspeech sounds, objective/physiological tests, and improving reliability, are relatively easy and are discussed first. The remaining questions involve issues of predictive validity—Can a particular result on a hearing test predict inability to work?—and are both complex and difficult; much of this section is devoted to a discussion of what is known and what is not yet known about these issues.

Nonspeech Sounds

Perception of nonspeech sounds is important in the workplace because many workers need to be able to detect, discriminate, recognize, and localize nonspeech sounds. However, there are no tests of discrimination and localization abilities of nonspeech sounds in routine clinical use today, and the committee therefore can make only recommendations for research in this area (see Research Recommendations 4-9 and 4-10). In contrast, the ability to detect nonspeech sounds such as warning signals can be predicted using procedures that take into account the intensity and frequency content of the signal and background noise, as well as the puretone thresholds (the audiogram) of the worker, with or without a hearing protection device (International Organization for Standardization, 1986).

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

Because jobs vary so greatly with regard to the need to hear warning signals (in many cases, accommodations such as visual warning signals can be substituted), and because the spectrum and level of specific warning signals would need to be known to predict signal audibility, the committee does not recommend their inclusion in the Social Security Administration (SSA) medical listings of Step 3. Rather, these issues are best dealt with in Steps 4 and 5 of the SSA process, when expert opinion on specific work conditions can be obtained.

Objective Tests

As described in Chapter 3, objective (physiological) tests, such as evoked potentials and otoacoustic emissions, are extremely useful for determining what part of the auditory system is affected in a person with hearing loss, and for testing persons who cannot or will not cooperate in behavioral testing. Nevertheless, in almost all cooperative adults, behavioral tests produce the best evidence of hearing abilities. For uncooperative adults, frequency-specific evoked potential threshold tests, while much more time-consuming than behavioral audiometry, provide good evidence of hearing loss, but only to the extent that they are known to correlate with pure-tone audiometry. These statements represent conventional wisdom in the international audiology community, and we are unaware of any data or even opinion to the contrary.

Improving Reliability

Current Step 3 procedures in adults require speech discrimination testing (which we refer to as speech recognition testing), but they do not specify several important variables: the word list used, recording versus live voice, the number of test words, the level of presentation, and whether people who use hearing aids or cochlear implants are tested with or without their devices. All of these variables affect the difficulty and the variability of speech tests. Recommended guidelines for speech testing used by SSA in Step 3 should control each of these variables to improve the reliability of speech testing.

Predictive Validity

The committee’s key task, a very difficult one, is to recommend standardized hearing tests that optimally predict the inability to work, taking into account issues of hearing aids, cochlear implants, non-English-speaking claimants, nonauditory deficits, and the hearing demands of different workplaces. This task can be approached as a problem in diagnostic test

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

accuracy (Swets, 1988). For any given test and cutoff (such as 40 percent correct on a test of word recognition, as in the current medical listings), a claimant will fall into one of four groups:

True positive (TP): test score is below cutoff and the claimant is in fact disabled.

False positive (FP): test score is below cutoff but the claimant can work.

True negative (TN): test score is above cutoff and the claimant can work.

False negative (FN): test score is above cutoff but the claimant is in fact disabled.

Obviously, TPs and TNs are accurate and desirable outcomes, and FPs and FNs represent undesirable errors. In general, the fewer errors the better, but what should be recommended if two tests (or two cutoffs) produce similar numbers of total errors but different proportions of FPs and FNs? For example, assume that for one group of 1,000 claimants the 40 percent cutoff on the speech test produced 20 FPs and 50 FNs. Assume further that a 60 percent cutoff produced 50 FPs and 20 FNs (because every additional TP reduces the number of FNs by one, an equivalent description of this hypothetical example would be that changing the cutoff from 40 to 60 percent produced marginal increases of 30 TPs and 30 FPs).

It would be impossible to choose one cutoff over the other based only on the total number of errors, but if one type of error were more undesirable than the other, one would pick the cutoff that minimized the more costly error. The costs of an FP error at Step 3 of the SSA disability process include reduced productivity from an individual who could be employed as well as the cost of SSA benefits. FN costs include the hardship of the wrongly denied claimant, although these costs can be reduced in Steps 4 and 5 of the process, in which a claimant denied in Step 3 may still be found to be disabled. If one test (e.g., word recognition) produced fewer of both types of errors than another (e.g., a sentence test), the choice of tests would be easy, but choosing the optimal cutoff would still involve a trade-off in which it is impossible to reduce one type of error without increasing the other. It is difficult to recommend optimal tests and cutoffs without specifying the relative costs of FP and FN errors; this would require a value judgment that is beyond the purview of the committee.

Regardless of the relative costs of FP and FN errors, if the “diagnosis” of a claimant for SSA is indeed “inability to engage in any substantial gainful activity,” there are strong reasons, discussed in Chapter 1, to believe that this cannot be done with perfect accuracy in a process, like

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

SSA’s Step 3, that considers only a claimant’s hearing test results. This is true—even if one were to limit oneself to predicting the ability to understand speech at work—because there are three sets of variables that interact in determining how well listeners can recognize, identify, and comprehend speech, but clinical hearing tests can address only one of these sets. Hearing tests do not evaluate nonauditory variables specific to the claimant (age, education, intelligence, motivation, native language, cognitive problems, etc.), nor do they evaluate the variable communication demands of different workplaces. The spectrum of communication demand in the workplace is nearly infinite, but a few examples illustrate the broad range of possibilities:

  1. Jobs in which accommodations for deaf and hard-of-hearing persons (e.g., email, instant messaging, and occasional use of interpreters) make it possible for them to function without ever needing to use speech communication;

  2. Jobs that require only occasional unhurried conversation, face-to-face in a quiet office, talking with familiar persons about familiar subjects, with the opportunity to ask for repeats and clarifications;

  3. Jobs that require frequent conversation with strangers about unfamiliar topics, often without the aid of vision (for example, on the telephone);

  4. Jobs that sometimes require rapid high-stakes responses to unpredictable messages that may come from distraught strangers who speak English poorly, in noisy backgrounds without visual input (a police officer or firefighter, for example).

Job type 1 requires no hearing. There must be many such jobs: 75 percent of working-age men who describe themselves as deaf are employed (Houtenville, 2002). Job types 2, 3, and 4 all require hearing ability, but many people who could perform job type 2 would be unable, because of hearing loss or nonauditory problems, to meet the communication demands of job types 3 and 4. Job type 4 probably requires an alert, motivated, trained person who hears as well as a typical healthy young adult. Without knowing the distribution of jobs with differing levels of communication demand available to people who apply for SSA disability, and without knowing the distribution of nonauditory characteristics among claimants, it is difficult to propose a Step 3 medical listing criterion that would be likely to accurately identify people as disabled in all cases.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

LIMITATIONS OF CURRENT FORMULA AND TESTING PROTOCOL

Hearing impairment in adults that qualifies for disability benefits under the existing SSA determination in Step 3 is a loss of hearing that is not restorable by a hearing aid. The current formula specifies that disability determination is met by documentation of average hearing thresholds (500, 1000, and 2000 Hz) of 90 dB hearing level (HL) or worse for air conduction stimuli and at maximal levels for bone conduction stimuli in the better ear or speech discrimination scores of 40 percent or less in the better ear. Expert testimony presented in the public forum held by the committee indicates that these criteria often fail to identify individuals who may be at risk in the workplace because of hearing loss, particularly those in hearing-critical jobs. There are several reasons for such failures:

  • The existing formula for disability determination for adults doesn’t take into account speech recognition performance at average conversational speech levels, which are likely to be encountered in everyday communication situations.

  • The current procedure doesn’t evaluate speech recognition in noise; poor speech understanding in noise could severely impair the ability to function effectively in many jobs that are dependent on oral communication.

  • The current procedures and formula do not consider performance with a hearing aid or implantable device. Actual performance with these devices cannot be predicted from unaided performance. Direct measures of performance with the assistive device and appropriate weighting to the disability determination formulas should reflect the extent to which the assistive device benefits an individual with hearing loss for certain hearing-critical job tasks.

  • The current protocol does not include assessment of sound localization, nor the ability to differentiate a change in an acoustic stimulus (i.e., sound discrimination). While these are fundamental hearing abilities, especially in certain hearing-critical jobs, there currently are no standard clinical methods of assessing these auditory functions. Research should be directed at this need.

  • The current formula doesn’t recognize that individuals with severe hearing losses (71-90 dB HL pure-tone average or PTA) cannot receive spoken communication auditorily without a hearing aid. Persons with severe hearing losses cannot detect the presence of conversational speech, nor can they accurately recognize the spoken message without a hearing aid. Many adults with severe hearing losses with early onset have not

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

been successful hearing aid users, as described in Chapter 5, and function primarily in the deaf world. They have been educated at schools for the deaf, including postsecondary schools for the deaf. It should be noted that postsecondary schools for the deaf, including Gallaudet University and the National Technical Institute for the Deaf, have an enrollment criterion of average hearing loss exceeding 70 dB HL. Employment data demonstrate that, on average, adults with severe and profound hearing losses (> 70 dB HL) have a lower rate of employment (Blanchfield, Feldman, Dunbar, and Gardner, 2001) and lower earnings than individuals with normal hearing (e.g., Houtenville, 2002). The committee is not aware of published data that indicate any differences in employment trends between persons with severe hearing loss and persons with profound hearing loss. Finally, Food and Drug Administration regulations state that adults with hearing losses exceeding 70 dB HL may be candidates for cochlear implants, in recognition of the limited benefit that these individuals may receive from amplification. Thus, claimants with severe hearing losses who do not wear hearing aids or cochlear implants have essentially no ability to hear or understand conversational speech in the workplace and may be placed at a significant disadvantage as a result.

GENERAL RECOMMENDATIONS

The foregoing discussion suggests that there is a fundamental contradiction between the SSA’s definition of disability based on a physical impairment and the reality of highly successful performance in the workplace by some individuals with these very same impairments. The committee deliberated about whether there should be medical listings at all. One could argue “no.” However, we do not recommend eliminating medical listings at this time because evidence is lacking about their current performance (i.e., the error rate inherent in Step 3 and the quality and uniformity of individual evaluations in Steps 4 and 5) and because there are clear advantages of medical listings as consistently applied criteria that are less costly than requiring all claimants to proceed directly to Steps 4 and 5.

The committee debated whether there should be changes in the current medical listings for Step 3. For example, we carefully examined the evidence for changing the PTA cutoff from 90 to 70 dB. We do not recommend a change in the PTA cutoff at this time because evidence is lacking about the accuracy of the current PTA cutoff in correctly identifying individuals with severe disability and correctly rejecting individuals without severe disability.

The committee also considered whether the speech recognition score cutoff should change from 40 to 50 percent correct, or whether the current

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

word recognition test should be replaced with a sentence recognition test. Again, we do not recommend a change at this time because evidence is lacking about performance of the current cutoffs and tests. In summary, there remain deficiencies in knowledge about the performance of current cutoffs in the medical listings, and it is difficult to recommend changes to them without knowledge of the performance of these criteria or alternatives to the existing criteria.

In contrast to the lack of data on the ability of clinical tests to predict ability to work, considerable research evidence now exists about the effects of procedural variables on the reliability and internal validity of performance on audiological tests. As a result, the committee is in a position to recommend removing ambiguities in the standard test protocol with the goal of improving the performance of the testing process. The principal recommended change to the disability determination process, therefore, consists of clarification of the methodological procedures used for the audiological assessment, which is expected to be useful for improving the reliability and validity of the test results. Additional test measures (e.g., speech recognition in noise) are recommended as part of the audiological assessment that will provide important documentation for decision points in Steps 4 and 5 of the SSA disability determination process.

The recommendations in this chapter are a refinement of the protocol for evaluating claimants for hearing impairment disability. The principal changes proposed for the evaluation of adults include testing speech recognition in the sound field while the claimant wears his or her own hearing aid or cochlear implant, in two conditions: (1) in quiet at 70 dB sound pressure level or SPL, using two 50-word lists of the Veterans Administration (VA) recordings of Northwestern University Auditory Test No. 6 (NU6) and (2) in two noise conditions (the noise is a single competing talker) using a single 50-word list in each noise condition, with speech presented at 70 dB SPL and noise presented at +10 dB and 0 dB signal-to-noise (S/N) ratios. If the claimant does not use a hearing aid or cochlear implant, then the speech recognition tests (quiet and noise) are presented to the listener in the sound field in the unaided mode (ears uncovered). An individual claimant is tested either in the aided mode or the unaided mode, but not both. The test in noise is included to provide relevant data for decisions in Steps 4 and 5. In addition, we propose adding a series of questions to be answered using a checklist during the audiological assessment to indicate the quality of the test results. A final recommendation for the protocol is to evaluate claimants who are nonnative speakers of English with speech recognition tests in their native language, if available.

There are no revisions proposed to the criteria for significant and disabling hearing impairment; rather, the existing cutoffs would be ap-

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

plied to measures obtained in very specific test conditions. Moreover, the criteria vary somewhat for claimants who wear a hearing aid or cochlear implant compared with claimants who are unaided. For claimants who do not wear a hearing aid or cochlear implant, the criterion for hearing disability is a PTA in the profound range (≥ 90 dB HL) or speech recognition performance less than or equal to 40 percent correct in quiet. For those claimants who wear a hearing aid or cochlear implant, the criterion for hearing disability is aided speech recognition performance less than 40 percent correct in quiet under specified test conditions.

These changes to the protocol are expected to yield an improvement in validity and can be supported by two generic examples:

  1. Under the current medical listings, many persons with severe hearing loss who are not cochlear implant users are denied eligibility because their PTA 512 is better than 90 dB HL and their speech recognition score, measured at unrealistically high presentation levels, is higher than 40 percent correct. Many of these individuals are false negatives. Specifying the presentation level of 70 dB SPL in the sound field will certainly reduce these false negatives (but will also create some new false positives, it is hoped few in number compared with the reduction in the number of false negatives).

  2. Under the current medical listings, assuming most SSA personnel don’t permit aided testing, virtually everyone with a cochlear implant is declared eligible. Clearly, many of these individuals are false positives because with the cochlear implant they can perform well in the workplace. Specifying aided sound field testing will certainly reduce false positives (but will also create some new false negatives, it is hoped few in number compared with the reduction in false positives).

SPECIFIC RECOMMENDATIONS

The following discussion on tests for disability determination applies to tests that may be used in Steps 2, 3, 4, or 5 of the SSA disability determination process. Any recommendations for medical listings (Step 3) are identified explicitly as such.

Otolaryngological Examination

Action Recommendation 4-1. The otolaryngological exam that is required for disability determination should be performed by an otolaryngologist certified by the American Board of Otolaryngology. The recommended examination is described in detail in Chapter 3. The committee

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

recommends that this examination follow the audiological testing, but by no more than six months. This reversal of the order of examinations from the current SSA guidance is based on the committee’s judgment that the results of audiological testing must be considered by the otolaryngologist in reaching his or her conclusions about the claimant.

Criteria for Selecting Tests for Disability Determination

The committee considered a number of different issues in developing criteria for the selection of tests to be recommended for use in disability determination. Some issues were specified by the SSA: the tests should be readily available at no additional cost to the agency, should be part of the standard of care, should yield reliable and valid data, and should provide good descriptors of human performance in the real world. The committee was steadfast to the principle that each test must have undergone rigorous testing procedures for standardization, so that the following characteristics of the test are known:

  • expected performance of individuals with normal and disordered auditory systems,

  • expected variability in performance,

  • expected performance at particular presentation levels and through particular transducers, and

  • test-retest stability.

Another highly desirable goal was to select tests for which correlations are known between performance on the test in specific conditions and actual performance in the workplace. We also sought tests that could be performed in unaided and aided listening conditions to indicate the benefit that a claimant receives from a hearing aid, cochlear implant, or other assistive listening device in real-world situations. Tests that could be performed by claimants who are nonnative speakers of English were also preferred.

Few tests examined by the committee met all of these criteria. As a result, we identified tests that met most of the principal criteria specified. We recommend use of the tests described in this section until such time as new tests are developed, or existing tests are modified, to meet all of the criteria stipulated. As acceptable tests become available, they should be considered by SSA for inclusion in the disability determination process. Specification of required standardization procedures is provided throughout this section for the benefit of individuals interested in developing tests for future use by SSA.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

The Test Battery Approach

Action Recommendation 4-2. In order to capture an accurate assessment of an individual’s hearing abilities on a given day, a test battery is recommended. The test battery approach permits a determination of the validity of the claimant’s responses by examining intertest agreement. If SSA continues to use both pure-tone and speech testing, then more than one test in the battery can be used to determine if an individual has met the requirements for a disability based on hearing impairment. A person who may not be able to take a particular test in the battery (e.g., because of a language barrier) may still have a successful claim on the basis of performance on other component tests in the battery. The measures to be assessed in the test battery for adults are:

  • pure-tone thresholds in each ear presented via air and bone conduction transducers,

  • speech thresholds using earphones in each ear,

  • speech recognition performance for signals presented in the sound field at average conversational levels in quiet and in noise,

  • tympanometry, and

  • acoustic reflex thresholds.

The latter two tests are included to rule out conductive pathology, because a conductive component to the hearing loss often can be managed medically with improvement in hearing sensitivity. In addition, acoustic reflex threshold assessment can be useful in identifying cases of feigning a severe or profound hearing loss that would be undetected by other tests in the battery. It is recommended that the entire test battery be completed before a determination of disability is formulated.

Personnel to Conduct the Testing

Action Recommendation 4-3. The test procedures required for determining a disability based on hearing impairment must be conducted by a clinical audiologist who holds state licensure (if applicable). Audiologists working in states in which no licensure exists should be certified by the American Speech-Language-Hearing Association (Certificate of Clinical Competence in Audiology, or CCC-A) or by the American Board of Audiology.

Audiologists are hearing health care professionals who identify, assess, and manage disorders of the auditory system of individuals across the life span and of individuals from diverse linguistic and cultural backgrounds. They follow a stringent code of ethics (American Speech-

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

Language-Hearing Association, 2002). A professional audiologist is deemed necessary because the recommended procedures include performing tests with the claimant’s own hearing aid(s) or cochlear implant(s) set to their optimal adjustments. The only professional who has the requisite knowledge, training, and clinical experience to perform these and other auditory tests comprising the test battery is the clinical audiologist.

Environment and Equipment for Testing

Action Recommendation 4-4

Test Environment

Audiological assessments are conducted in controlled acoustic environments to minimize the detrimental and unpredictable effects of background noise. The environment for assessment of auditory threshold must conform to standards of the American National Standards Institute (ANSI) for limits on maximum permissible ambient noise levels (American National Standards Institute, 2003a). The presence of noise in excess of these required levels produces shifts in measured auditory thresholds, particularly for low-frequency sounds.

The reverberation characteristics of the test environment should also be controlled if sound field measures are conducted. Reverberation refers to the prolongation of sound in a room, resulting from reflections of sound at the boundaries of the room enclosure. Reverberation is quantified by the reverberation time, defined as the duration, in seconds (sec), for a signal to decay 60 dB below its steady-state value after termination. The recommended reverberation time for the audiometric environment is 0.2 sec or less (American Speech-Language-Hearing Association, 1991a). Control of both noise and reverberation can be achieved with double-walled sound-attenuating chambers.

Equipment for Testing

The principal equipment used for behavioral assessment of auditory thresholds and speech recognition is the audiometer. The audiometer generates pure-tone signals and can present speech signals that are either live voice or prerecorded. The examiner controls signal intensity, stimulus temporal characteristics, and signal transducer (earphones, bone conduction vibrator, or loudspeaker). ANSI Standard S3.6-1996 (American National Standards Institute, 1996) specifies the reference-equivalent threshold sound pressure levels (RETSPL) for signals presented via earphones and loudspeakers, as well as reference-equivalent threshold force

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

levels (RETFL) for signals presented via bone conduction transducers. These terms (RETSPL and RETFL) refer to the sound pressure levels or force levels of explicit signals (pure tones and speech), presented via specific transducers, that correspond to the average threshold of hearing in young adult listeners with normal hearing. A full electroacoustic calibration of audiometric equipment to these reference levels (or those specified in future, revised ANSI standards) should be conducted initially with new equipment and annually thereafter (American Speech-Language-Hearing Association, 2002).

Other types of audiometric equipment are used for the electrophysiological measures described in other sections of this report. Acoustic immittance meters measure the admittance of the middle ear system and are employed in assessment of middle ear function (tympanometry and acoustic reflexes). Calibration of these devices is detailed in ANSI Standard S3.39-1987 (R2002) (American National Standard Institute, 2000b). Auditory evoked potentials (e.g., electrocochleography, auditory brainstem response or ABR—see the section later in the chapter) and otoacoustic emissions (e.g., transient-evoked otoacoustic emissions, distortion product otoacoustic emissions) can be measured with clinical instruments or more sophisticated laboratory equipment. As of this writing, there are no national standards governing the calibration of this type of equipment. However, electroacoustic equipment should be calibrated to conform to the manufacturer’s specifications, when appropriate (American Speech-Language-Hearing Association, 1993). All power-line-operated instruments must also satisfy minimum ANSI safety requirements for grounding and levels of electrical stimulation (American National Standards Institute, 1993).

A stringent protocol for infection control is used for all audiometric equipment (Cohen and McCullough, 1996). In particular, any audiometric supplies that come into direct contact with the external auditory canal (such as ear tips) must be either discarded after a single use or sterilized to prevent the spread of infectious disease.

The Checklist

Action Recommendation 4-5. The committee recommends that SSA require a checklist to accompany all hearing test results obtained for adults who are filing a claim for hearing disability. The checklist should be completed by the clinical audiologist at the time of the test and submitted with other data as part of the claim for disability. (Item 5 should be completed by the audiologist or the otolaryngologist, whoever is last to examine the claimant.) Thus, any individual interested in filing a disability

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

claim based on hearing loss must ensure that the checklist is completed at the time of the audiological examination. The checklist is an indication of the quality of the data collected to be used in the disability determination process and includes additional useful information for evaluating a claim in Steps 3, 4, and 5. Checklist items, together with the rationale for their selection, appear throughout this section. The complete checklist is presented in Box 4-1, with a notation of answers that are unacceptable and thus require retesting. If any answers are missing or not satisfactory, the examination report should not be accepted for use in disability determination.

Brief Case History

A brief case history should be obtained prior to the hearing assessment for disability determination. The case history ensures that the individual is not experiencing temporary conditions that may affect the accurate assessment of hearing acuity. Essential questions to be asked during this brief case history pertain to recent noise exposure that may produce a temporary threshold shift. It is recommended that an individual not be tested if there is a history of recent noise exposure (within 72 hours) or if hearing sensitivity is noticeably poorer on the exam day, in cases of fluctuating hearing loss. Another important issue is whether the person experiences a fluctuating hearing loss. If the hearing isn’t stable, this would suggest the need for additional testing.

CHECKLIST ITEM 1: Does the claimant work in a noisy environment?

CHECKLIST ITEM 2: Is there a history of significant noise exposure in the past 72 hours?

CHECKLIST ITEM 3: Does the claimant report a fluctuating hearing loss? If so, was the claimant tested on a day when his or her hearing was noticeably poorer?

A person’s performance on some auditory tasks is often a function of the age of onset of hearing loss and mode of onset (sudden versus gradual). Adults who have a recent, sudden onset of hearing loss sometimes exhibit particular difficulty on audiological measures. A checklist item is included that inquires about mode of onset and, if sudden, if it was recent. For a very recent hearing loss, a second audiogram may be advised, after the claimant has had more time to adjust to the loss.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

BOX 4-1
Checklist for Disability Determination

The following questions must be answered “Yes” or “No.” A response that falls in a shaded box indicates that the test results are not acceptable. The test must be repeated on another day.

Item

Response

1. Does the claimant work in a noisy environment?

2. Is there a history of significant noise exposure in the past 72 hours?

3. Does the claimant report a fluctuating hearing loss? If so, was the claimant tested on a day when his or her hearing was noticeably poorer?

4. Did hearing loss begin suddenly? If so, did it begin recently (in the past year)?

5. Is the time between the medical exam and the audiometric exam 6 months or less?

6. Did the audiologist obtain a speech recognition threshold with respondees?

7. Did the evaluation yield information indicating that the test results appear to be valid? (Judgment based on PTA-SRT agreement, communication skills during the case history, and interlist consistency of speech recognition performance.)

8. Does the claimant wear a hearing aid, cochlear implant, or other device?

9. If yes, was the claimant tested with the hearing aid, cochlear implant, or other device?

10. Has the claimant been using a hearing aid or cochlear implant for a sufficient duration to derive maximum benefit from it?

11. Answer both (a) and (b), based on your professional opinion: (a) Has the claimant been tested with a reasonably optimal amplification system or coclear implant?

(b) Is this person a candidate for either a hearing aid or a cochlear implant at this time?

12. Is the claimant required to use hearing protection on the job?

CHECKLIST ITEM 4: Did the hearing loss begin suddenly? If so, did it begin recently (in the past year)?

CHECKLIST ITEM 5: Is the time between the medical exam and the audiometric exam 6 months or less? (To be completed by professional who is the last to examine the claimant.)

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

Rationale and Procedures for Pure-Tone Testing

An essential component of the test battery is an assessment of the softest sounds an individual can detect. The standard pure-tone threshold audiometric test for stimuli presented via earphones (air conduction) and via a bone oscillator (bone conduction) is required for this purpose. The test frequencies include the octave intervals from 250 to 8000 Hz for air-conducted stimuli, and from 250 to 4000 Hz for bone-conducted stimuli, with masking used as necessary to eliminate stimulus perception by the nontest ear. The resulting pure-tone audiogram will permit a determination of the degree and type of hearing loss, as well as the relationship of the hearing sensitivity between the two ears.

The pure-tone test must be conducted without the use of a hearing aid or cochlear implant (unaided). That is, any device must be removed from the claimant in order to conduct the test. Even if an individual wears a cochlear implant, it is necessary to assess hearing sensitivity bilaterally as part of the record, and because there may be some residual hearing in the unimplanted ear.

Generally, a single audiogram is required for disability determination. If an individual reports being in a noisy environment within the past 72 hours, he or she must return for testing another day when they have been free of noise exposure for at least a 72-hour period of time. This is the amount of time required for recovery from a temporary threshold shift resulting from most forms of noise exposure. However, if there is a recent history of acoustic trauma (i.e., exposure to a blast or explosion) or of the use of ototoxic drugs, then a repeat audiogram may be necessary after 3-6 months recovery time (Pahor, 1981; Segal, Harell, Shahar, and Englender, 1988). A second audiogram may also be obtained in cases of fluctuating hearing loss, recent head trauma, or very recent, possibly unstable, hearing loss, when the audiologist makes this determination.

The pure-tone audiogram is useful for predicting speech recognition performance at average conversational speech levels (60-70 dB SPL) in quiet. It is an independent measure of hearing sensitivity, regardless of an individual’s use of amplification. Pure-tone threshold testing can be completed successfully regardless of an individual’s native language (assuming that test instructions are given appropriately); thus it is free of possible language barriers that can impede performance on speech recognition measures. An individual’s performance on a standard puretone threshold test may also indicate signs of feigning a hearing loss or exaggerating a true hearing loss.

Pure-tone thresholds are measured with high test-retest reliability in cooperative adults (Carhart and Jerger, 1959). The 95 percent confidence interval for a measurement of pure-tone threshold is about ± 5 dB (Brown,

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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1948; Robinson, 1960). Because audiometric thresholds vary over about 100 dB, the confidence interval is about 10 percent of this range. Thus, pure-tone audiometry has been considered a relatively reliable test. Its validity has been tested by many studies comparing average pure-tone thresholds (most often for 500, 1000, and 2000 Hz, referred to in this report as PTA 512) to self-report using a variety of questionnaires that assessed hearing difficulties in everyday life (reviewed by Hardick, Melnick, Hawes et al., 1980; King, Coles, Lutman, and Robinson, 1992). Correlation coefficients typically ranged from 0.5 to 0.7, representing a moderately strong relationship between pure-tone thresholds and self-report. The pure-tone audiogram has been the standard test procedure for disability determination in the past. As a consequence, a comparison can be made between previous hearing test results and current test results, to determine if there has been a significant change in hearing sensitivity over time.

As described earlier, the committee decided to recommend no change in the medical listing criteria for pure-tone audiometry: 90 dB for PTA 512. We debated not only the “cutoff” of 90 dB but also the choice of PTA 512. It is clear that people with hearing loss limited to frequencies above 2000 Hz have more trouble in difficult listening situations, such as identifying isolated words in a noisy background without being able to see the speaker, than do normal listeners (e.g., Suter, 1985). Because of this, the American Medical Association and most state workers’ compensation programs use PTA 5123 (adding 3000 Hz) as the variable on which “binaural hearing impairment” and monetary compensation are based. For the same reason, in Chapter 7 we recommend that disability for children, which begins in the mild range of hearing loss, should also consider frequencies above 2000 Hz. Nevertheless, we recommend that SSA retain the use of PTA 512 for adult disability determination for several reasons:

  1. As is true for the 90 dB cutoff, there are no data to show that any other pure-tone audiometric variable would perform better in predicting an inability to work.

  2. Frequencies above 2000 Hz appear to be less important for people with severe to profound hearing loss than for people with mild hearing loss (Webster, 1964). The Step 3 medical listings currently are applied at the boundary between severe and profound hearing loss.

  3. Most research describing the problems and auditory performance of people with severe or profound hearing loss has used PTA 512 as the relevant classifying variable (e.g., Blanchfield et al., 2001; Corthals, Vinck, De Vel, and Van Cauwenberge, 1997; Flynn, Dowell, and Clark, 1998). We know of no study showing that another frequency combination correlates better than PTA 512 with the hearing difficulties of such people.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×
  1. The demonstration that frequencies above 2000 Hz can make a difference in difficult situations cannot be extrapolated to a conclusion that they are as important as lower frequencies across the range of listening situations in everyday life. The research cited above does not demonstrate that any other frequency combination generally correlates better than PTA 512 with self-reported hearing problems. One reason for this finding may be that many everyday listening situations permit the use of vision; visual cues are complementary to low-frequency auditory cues and somewhat redundant with high-frequency cues. Another reason is that many everyday conversations take place in relatively quiet places and involve sentences rather than isolated words; both of these factors reduce the relative importance of high-frequency auditory cues.

There are many cases in which hearing sensitivity changes over time, especially cases of presbycusis, recent ototoxicity, and continuing noise exposure. In order to present a consistent report of findings to SSA, it is strongly recommended that the time interval between the audiometric assessment and the otological evaluation be 6 months or less. However, this may not always be reasonable in certain health care settings. If the audiogram is more than 6 months old and the claimant does not meet the listings, SSA may request a new audiogram.

Rationale and Procedures for Speech Threshold Testing

A speech threshold is a required measure in the test battery for the primary purpose of cross-checking the validity of the pure-tone audiogram and indicating the person’s ability to detect and recognize speech. The standard procedure is to measure a speech recognition threshold (SRT) using recorded spondees and a descending procedure (American Speech-Language-Hearing Association, 1988). A checklist item should be completed to indicate that standard test stimuli were used for assessing the speech threshold.

CHECKLIST ITEM 6: Did the audiologist obtain a speech recognition threshold with spondees?

The SRT should agree within ± 6 dB with the three-frequency PTA (500, 1000, 2000 Hz) (Wilson and Strouse, 1999) or with the Fletcher average (average of two best thresholds obtained between 500 and 2000 Hz) in cases of audiograms for which the threshold at 2000 Hz differs from the threshold at 500 Hz by 20 dB or more (Fletcher, 1950). In the event that an individual cannot repeat the spondee words at suprathreshold levels, a speech detection threshold (SDT) should be measured.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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In listeners who can perform both measures, the SDT is obtained at levels that are 8-12 dB better (lower) than the SRT because the SDT requires simple detection while the SRT requires detection and recognition. Because the SDT is obtained at relatively low levels, the SDT is expected to be better than the PTA by 2 to 18 dB. However, because detection thresholds are measured in both the SDT and pure-tone thresholds, the SDT generally corresponds to the best pure-tone threshold (Campbell, 1998). The audiogram forms should indicate the procedure, SRT or SDT, that was used in the assessment.

Consistency between the speech threshold and the pure-tone thresholds indicates that the audiogram is probably valid, and that should be noted on the following checklist item. In evaluating the validity of the hearing test results, the audiologist also should consider the claimant’s communication skills during the case history and the overall consistency of speech recognition performance, in relation to the pure-tone audiogram. If the test isn’t valid, it should be repeated and, if still invalid, the patient should be tested using auditory evoked potentials.

CHECKLIST ITEM 7: Did the evaluation yield information indicating that the test results appear to be valid? (Judgment based on PTA-SRT agreement, communication skills during the case history, and interlist consistency of speech recognition performance.)

If a claimant is not a native speaker of English, a recommended modification of the standard procedure for measuring SRT is to present digit pairs in place of spondee words. If the claimant is unable to identify these items with a verbal or a pointing response, then a SDT should be assessed.

Criteria for Selecting a Speech Recognition Test for Disability Determination

The ability to understand conversational speech in quiet and in noise is essential to communication in a range of work settings. For SSA disability determination, it is important to assess speech recognition performance in quiet to predict the extent to which an individual can receive instructions and communicate orally with coworkers, clients, patients, supervisors, and students in quiet listening environments. Because many work environments have noise backgrounds, assessment of speech understanding performance in simulated noise conditions is also important to predict the communication function of workers in these typical situations. The preferred procedure for assessing speech recognition for disability determination would be one that replicates a typical communication in-

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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teraction in the workplace, including the type of communication message, the sex of the talker, the sound pressure level of the speech signal, the acoustic characteristics of the environment (presence of noise, S/N ratio, presence of reverberation, and reverberation time), and the ability to see the speaker’s face. The closer the correspondence between the stimuli and procedures of the speech recognition test and communication in the workplace, the better the clinical test ought to predict performance in the workplace. Conversely, the more the test conditions simulate the claimant’s specific job, the less standard the testing will be across claimants. This could result in a problem of perceived fairness.

The ideal assessment to determine an individual’s disability in the workplace would be to conduct a task analysis of the communication demands placed on the worker, determine job-specific phrases in that work setting, assess typical background noise levels and speech levels experienced by the worker in the field, and attempt to closely approximate the work setting in the clinical audiometric assessment of the individual. Although this approach is expensive, it is at the very heart of the process of identifying actual disability on an individual basis. SSA should consider developing strategies to facilitate this type of work-related disability assessment for hearing impairment. Nevertheless, at the present time there is a gap in knowledge about the relationship between the communication performance of workers in real-world communication settings and speech recognition performance on current clinical procedures, and data are urgently needed to examine this relationship. Until evidence is available establishing a close link between clinical tests and actual performance in the workplace, SSA must rely on a set of commonsense principles to use in recommending appropriate tests for evaluation. To that end, the committee developed a set of specific criteria to use in selecting clinical speech recognition tests for disability determination at the present time. These specific criteria are in addition to those described above in the section on criteria for selecting tests for disability determination.

A basic principle is that a speech recognition test is a specific recording of test materials. A speech recognition test without recorded materials is unacceptable for disability determination for adults. In addition, if more than one recording of a set of speech materials is available, only the recorded version that conforms to the specified requirements may be used in the evaluation.

The first criterion in selecting a speech recognition test is that normative data must be available for the recorded test conducted both in quiet and in noise. The rationale for this requirement is that use of the same measure for testing in quiet and in noise permits a direct assessment of the impact of the noise environment on communication.

A second criterion for the speech recognition test is that normative

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

data must be available for the speech signals presented at SPLs representing typical speech levels encountered in communication. Specifically, normative data must be available for a typical speech level of 60-70 dB SPL in the sound field (or equivalent level in dB HL), which is within the range of everyday conversational speech levels.

A third criterion for the speech recognition test is that normative data must be available for background noise presented at typical S/N ratios encountered in daily communication. A single S/N ratio representative of work settings is difficult to quantify, as noted above. An alternative to testing performance at one “average” S/N ratio is to evaluate performance at two S/N ratios that represent a moderate noise level and a more challenging noise level, such as +10 dB and 0 dB, respectively. A moderate S/N ratio is observed in many acoustic environments in which communication takes place with a slight noise background; the more severe S/N ratio represents only the most challenging communication situations. The more severe S/N ratio (0 dB) may be important for predicting communication performance in hearing-critical jobs known to have high noise levels.

Extrapolation of data published by Wilson et al. (1990) indicates that people with normal hearing score approximately 87 percent correct (standard deviation approximately 3.8-5.0 percent) at the more favorable S/N ratio condition of +10 dB. People with normal hearing score approximately 63 percent correct (standard deviation = 8 percent) in the more severe S/N ratio condition of 0 dB, on the VA compact disc version of the VA-NU6 with a single competing talker (Wilson et al., 1990). The committee recommends that this kind of additional testing in noise should be conducted for all claimants and should be included to provide data for expert opinion in Steps 4 and 5. Determination of significant difficulty in noise should be made after consideration of normal listeners’ performance in noise, which, as noted above, is often less than optimal.

At the present time, there is only one speech recognition test that meets these three basic criteria: the VA compact disc (versions 1.0 and 1.1) of the NU6 test (Tillman and Carhart, 1966), as described in the normative studies by Wilson et al. (1990) and Stoppenbach et al. (1999) (henceforth referred to as VA-NU6).1 While some limitations are noted with this test, particularly the use of monosyllabic words and only four equivalent lists, it is the only test for which normative data are available in quiet and in competition at typical S/N ratios. This version of the NU6 is the only test

1  

The web site www.va.gov/621quillen/clinics/asp/products contains details and order-ing information about the test. We recommend that SSA work with the VA to acquire a license for the test and to develop a mechanism for mass distribution of this material to audiologists conducting assessments for disability determination.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

identified by the committee that meets the recommended criteria for SSA disability determination. It should be noted that the calibration tone for the VA-NU6 test reflects the peaks of the carrier phrase. Thus, the root-mean-square (RMS) level of each test word is slightly lower than that of the calibration tone.

The “competition” or “noise” in this test consists of sentences spoken by a single talker. The single-talker competition was chosen rather than a broadband noise competition because for this version of the VA-NU6 test, the mean speech recognition performance levels of listeners with normal hearing are within the range 50-90 percent correct, over the S/N ratios of interest. Specifically, listeners with normal hearing exhibited mean speech recognition scores of approximately 87 percent and 63 percent at +10 dB and 0 dB S/N ratios, respectively, for the single-talker competition, but only 47 percent and 8 percent, respectively, for the broadband noise competition. There was a concern that measuring the performance of listeners with hearing impairment in the broadband noise competition at typical S/N ratios where listeners with normal hearing score so low would always result in floor effects. More importantly, using a single-talker masker gives the potential to identify listeners with hearing loss who are especially disadvantaged by background noise situations that are very little trouble to many other listeners. These are the individuals who may score considerably above 40 percent in quiet but less than 40 percent in noise at the +10 dB S/N ratio. This is because they are not able to take full advantage of the periodic dips in the level of the masker. The purpose for testing in noise is to identify persons for whom working in a noisy situation is worse than one might ordinarily predict. The committee determined that a single-noise masker is a good choice for that task.

The recommended protocol includes presentation of two 50-item lists of VA-NU6 for testing in quiet. Percentage-correct scores should be derived for each of these 50-item lists and compared. In addition, a composite score based on all 100 items should be derived if the two 50-item scores are within the maximum acceptable test-retest differences, as shown in Table 4-1. This table was constructed using Thornton and Raffin’s data (1978, p. 515) (n-50 column) showing maximum acceptable differences (p > .05) between the two 50-word scores. Comparing the two 50-word scores permits the audiologist to determine whether or not the difference between the two test scores is within the expected normal variability. If the intertest difference exceeds the table entries, the test should be considered invalid. For example, if the lower score obtained for the two tests is 20 percent, then the higher score should be 36 percent or less for the two scores to be considered valid. In addition, the combined 100-word score has better reliability than a 50-word score. For example, the 95 percent confidence interval for a score of 40 percent on a

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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TABLE 4-1 Maximum Acceptable Test-Retest Differences for 50-Word Test Scores

If the lower score is:

Then the difference should be no greater than:

0 percent

4 percent

2

8

4

10

6

12

8 to 12

14

14 to 20

16

22 to 60

18

62 to 70

16

72 to 78

14

80 to 82

12

84 to 86

10

88 to 90

8

92

6

94 to 96

4

98

2

 

SOURCE: Based on Thornton and Raffin (1978, Table 4, p. 515).

50-word list is 26 to 58 percent, but for a 100-word score, the 95 percent confidence interval is narrower, 30 to 50 percent.

The recommended protocol also involves presentation of one 50-item list of the VA-NU6 test in competing message (single-talker competition) at +10 dB S/N ratio and one 50-item list in competition at 0 dB S/N ratio. The level of the speech signal is constant at 70 dB SPL. The nominal 70 dB SPL for the VA-NU6 test is actually a frequent-peak level. The long-term RMS level is closer to 65 dB SPL, comparable to the long-term RMS level of conversational speech. All speech recognition testing is conducted in the sound field with speech and competition presented through a single loudspeaker located at 0° azimuth at a distance of 1 meter from the listener. Stimuli presented in the sound field should be calibrated according to methods specified in ANSI S3.6 (American National Standards Institute, 1996). Additional issues regarding sound field measurements, including equipment specifications, the environment, and control of extraneous variables, can be found in American Speech-Language-Hearing Association (1991b).

Other tests may be developed or modified to meet the criteria listed above, and indeed this is encouraged, especially for tests that use everyday sentences or job-related phrases. There is some concern, however,

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

that other tests will not yield equivalent scores to the VA-NU6, and results obtained with these tests will be difficult to interpret in relation to cutoff values established for VA-NU6. To be acceptable for use in disability determination, other tests must undergo rigorous standardization procedures. These standardization procedures include demonstrating the equivalence of scores on the new test relative to the VA-NU6 version for standard presentation levels and noise levels with the same group of listeners, the equivalence of scores on different lists of the new test, the content validity, and the test-retest reliability of the new test.

In addition to these requirements for any new test, there are preferred characteristics for tests to be developed. These characteristics include stimuli that reflect everyday speech, recorded versions that are standardized on listeners with normal hearing and with hearing loss, recordings in the most common non-English languages spoken in the United States that are standardized on native speakers of those languages, evidence of reliable scores, availability of numerous equivalent lists, procedures that minimize the influence of cognitive factors, a reasonable administration time, and known psychometric properties (i.e., performance-intensity functions). It would also be valuable for test developers to derive the frequency importance function, which indicates the relative importance of individual spectral regions for a particular set of speech materials, to improve the accuracy of articulation index (AI)/speech intelligibility index (SII) calculations, as well as the transfer function for the new speech material, which is a function relating the speech intelligibility score to the SII (American National Standards Institute, 2002e). The transfer function will depend on the syntactic, semantic, linguistic, and contextual information being transmitted, as well as the characteristics of the talkers and listeners; it will be useful for comparing expected performance on the new test to expected performance on other available speech recognition tests.

Many promising tests are currently available but not yet recommended for use in disability determination. One example is the Hearing in Noise Test (HINT) (Nilsson, Soli, and Sullivan, 1994). A notable advantage of the HINT is that recordings are available in several languages, in addition to English. This test meets many of the other desired characteristics of a recommended test, but it is not easy to obtain the test without purchasing additional equipment, the cost is high, and the test was standardized as a threshold test rather than a suprathreshold test presented at typical speech levels. The scores on this sentence test that would yield performance equivalent to scores on the VA-NU6 are not known.

Another attractive test is the QSIN (Etymotic Research, 2001), which involves presentation of sentence materials at multiple S/N ratios. However, normative data are not yet available for this test.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

RECOMMENDED PROTOCOL (STEPS 3, 4, AND 5) AND MEDICAL LISTING FORMULA (STEP 3)

The broad objective of the recommended disability determination for adults is to identify individuals who are unable to perform on the job because of the limitations imposed by significant and permanent hearing loss. The basic premise in determining the criteria is that an individual who cannot hear speech at a conversational level, or who understands fewer than 40 percent of isolated words without contextual cues in a typical listening environment, has a significant hearing disability. The recommended protocol and cutoffs for disability determination are intended to reduce the likelihood of failing to identify an individual with hearing loss who cannot function in a particular workplace. The methods used to accomplish this include evaluating claimants on speech recognition tests presented in the sound field at conversational speech levels and retaining the 40 percent cutoff for speech recognition performance in this condition for the Step 3 medical listing. The testing of claimants with their own hearing aids or cochlear implants in this condition is expected to reduce the likelihood of identifying people as disabled who are able to function well in the workplace with their own devices. In addition, testing in noise is recommended for the basic protocol at two S/N ratios; this information will be useful for evaluation of a claim in Steps 4 and 5.

There is very little research-based evidence to link performance on clinical audiometric tests with actual performance in the workplace, and this is perhaps the most pressing research recommendation for the SSA. Lacking empirical evidence, the committee relied on its collective expertise to develop a set of linkages between performance on clinical tests and expected performance on work-related hearing-critical tasks, presented in Table 4-2. On the basis of this framework, clinical test results indicating that an individual cannot hear conversational-level speech (as is the case for a claimant with a severe hearing loss who doesn’t use a hearing aid), or understands no more than 40 percent of isolated words in a typical listening environment with minimal contextual cues and no visual cues, should be interpreted as showing that the claimant has a significant hearing disability.

The recommended formula does not change the medical listing for hearing impairment in Step 3. Rather, it changes the procedures for assessment that should significantly impact outcomes in Step 3. The current SSA formula defines hearing disability for claimants who do not use a hearing aid or a cochlear implant as a sensorineural hearing loss of 90 dB HL or worse in the better ear, based on the air conduction PTA of 500, 1000, and 2000 Hz and bone-conduction thresholds at the limits of the test equipment. A person with these audiometric characteristics cannot detect

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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TABLE 4-2 Relationships Between Performance on Audiometric Tests and Performance on Work-Related Hearing-Critical Tasks

Test Type

Performance Level

Expected Performance in the Workplace

Pure tones

PTA 512 ≥ 90 dB HL

Unable to hear or understand conversational-level speech; may detect amplified sounds only.

Pure tones

PTA 512:71-89 dB HL

Unable to hear or understand conversational-level speech; will detect amplified speech; distortion of amplified speech usually present; hearing loss sufficient to render the individual a visually oriented person; may or may not be able to understand speech with a hearing aid without visual cues.

NU6 speech test in sound field at 70 dB SPL, in quiet

0-40 percent correct

Very poor word recognition performance in quiet; unable to understand most spoken words without contextual cues and without visual cues.

 

 

Severely limited ability to follow novel auditory-only words embedded in instructions in the workplace.

 

 

Severely limited ability to understand individual spoken words using the telephone.

 

 

Severely limited ability to understand televised or videotaped spoken words if speaker is off-camera.

 

 

Severely limited ability to understand a lecture if seated at a distance (unable to see the speaker’s face).

 

 

Severely limited ability to follow individual words in a conversation at a meeting when the talker or topic is switching.

NU6 speech test in sound field at 70 dB SPL with noise (+10 dB S/N ratio)

0-40 percent correct

Very poor word recognition performance in moderate noise levels.

 

Severely limited ability to follow individual spoken words while using the telephone in a typical office environment (i.e., with moderate noise, such as background of people talking, office machinery noise, phones ringing, etc.).

 

 

Severe difficulty understanding individual words in unfamiliar phrases, when there are limited contextual cues and no visual cues in a typical office environment (i.e., with moderate noise, such as background of other people talking, office machinery noise, phones ringing).

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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Test Type

Performance Level

Expected Performance in the Workplace

 

 

Severe difficulty understanding shouted individual words with a background of moderate-level equipment noise.

NU6 speech test in sound field at 70 dB SPL with noise (0 dB S/N ratio)

0-40 percent correct

Very poor word recognition performance in high noise levels.

 

Severely limited ability to understand individual words in unfamiliar phrases, when there are limited contextual cues and no visual cues in environments with high noise levels.

 

 

Severe difficulty understanding shouted individual words with a background of high-level equipment noise.

conversational-level speech without amplification and, as a result, has such limited audibility without a hearing aid or cochlear implant that they could not converse in most settings without visual cues.

The committee carefully weighed lowering the PTA criterion to 70 dB HL (severe hearing loss). However, data do not currently exist on employment trends for individuals with severe hearing losses, and it is difficult to determine the specificity and sensitivity of a change in the medical listings. As a result, the committee recommends retaining the medical listing in Step 3, based on PTA, until additional data are available (see research recommendations).

An alternative criterion in the recommended hearing disability formula is a speech recognition score of less than or equal to 40 percent correct, for speech stimuli presented at an average conversational level (70 dB SPL) in the sound field at 0° azimuth (directly in front of the listener) in quiet. Two full lists (50 words each) of the VA-NU6 test should be presented and a composite score derived (i.e., percentage correct out of 100 items). Claimants who wear hearing aids or cochlear implants are tested only in the aided condition, using their own hearing aids or cochlear implants set to the usual settings. If the claimant does not own a hearing aid or cochlear implant, he or she should be tested unaided with both ears uncovered. Individuals who meet the recommended medical listing for speech recognition are unable to understand most isolated words in sentences spoken at an average conversational level without visual or contextual cues.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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Although it is true that there are no published reports of standardization of the recommended aided testing procedure, there is considerable published research supporting the use of monosyllabic word tests presented in the sound field at an average conversational level. For example, Larson et al. (2000) evaluated 360 individuals with moderate hearing impairment using NU6 words presented in the sound field in quiet at a conversational speech level in unaided and aided conditions. Mean unaided performance was approximately 58 percent correct and mean aided performance was approximately 88 percent correct. Similarly, Flynn et al. (1998) used a comparable procedure for assessing aided performance in individuals with severe and profound hearing losses. A number of studies have also assessed the performance of cochlear implant users with NU6 words presented in the sound field at average conversational levels (Fishman, Shannon, and Slattery, 1997; Tyler, Fryauf-Bertchy, Gantz, Kelsay, and Woodworth, 1997) or with other similar monosyllabic word recognition tests (e.g., Skinner et al., 2002). Thus it appears that use of the recommended test procedures is common practice for evaluating listener performance with hearing aids or cochlear implants, and that aided performance with these devices often demonstrates improvement over unaided performance.

The criteria above apply to the use of recorded, standardized speech materials, such as the VA-NU6 test (Wilson et al., 1990). Other speech recognition tests may be used in place of the VA-NU6, but the cutoff score for the disability criterion must be adjusted to the 40 percent equivalent score of the VA-NU6, delivered at a speech presentation level of 70 dB SPL in quiet. The equivalent scores must be established in the same subjects in a research study and must appear in a peer-reviewed publication prior to adoption for SSA disability determination.

The committee recommends that the standard audiometric protocol should include speech recognition testing in noise. As in the quiet situation, claimants should be tested with their own hearing aids or cochlear implants, adjusted to the usual settings, or unaided if the claimant does not use a hearing aid or cochlear implant. The recommended test is the VA-NU6 test presented at a speech level of 70 dB SPL with a single competing talker at two S/N ratios: +10 and 0 dB. A single, full (50-item) list is sufficient for each of these conditions. Both the speech and the noise (competing talker) should be presented through a single loudspeaker in the sound field, located at 0° azimuth. The +10 dB S/N ratio is intended to capture the acoustic characteristics of typical, moderate noise environments, whereas the 0 dB S/N ratio simulates work settings characterized by high noise levels. High noise levels are found in industrial settings with heavy machinery, on the runway at airports, inside the cab of trucks,

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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at construction sites, inside homes and offices during cleaning with machinery, and in restaurants and bars, among others.

The selection of a single-talker competition in the evaluation protocol is somewhat of a compromise. The committee sought to include a speech recognition test in noise in the SSA disability determination process that conformed to the criteria stipulated above. As noted, there was only one recorded, standardized speech recognition test at the time of this writing that satisfied these criteria: VA-NU6. Although this recording of VA-NU6 words has been standardized with both a single-talker competition and a broadband noise competition, the performance of normal-hearing listeners in the broadband noise competition was extremely limited, suggesting that this noise would not be practical for testing listeners with hearing impairment.

Nevertheless, the committee recognizes that there are some limitations inherent in the use of a single competing talker. The level of the single-talker masker will vary with time; the level will decrease during the pauses between words and during the lower level parts of speech. Speech recognition scores with a single-talker masker will generally be higher than with a steady-state masker, because listeners can take advantage of the momentary improvements in S/N ratio that occur during the dips in the noise level. However, listeners with hearing loss may not be able to take advantage of these dips as well as listeners with normal hearing for various reasons.

A second issue relates to “informational masking” or the nonenergetic masking that occurs due to the perceptual similarity between the signal and the masker. Steady-state noise creates a direct covering of the target signal through energetic masking, but a background noise consisting of talkers creates informational masking in addition to the energetic masking. Thus, some of the advantage of the single-talker masker that results from improved S/N ratios during the dips may be minimized due to informational masking. This discussion underscores the need for additional research aimed at developing speech tests in noise using background noises that simulate different listening environments consisting of talkers or steady-state noise or both, and typical S/N ratios (see Research Recommendation 4-2).

When claimants are tested in the more severe noise condition (S/N ratio = 0 dB), their performance should be compared with normative data collected under the same test conditions. It is suggested that a criterion for disability in this condition should be at least two standard deviations below mean normal performance, and it is at the discretion of the expert providing an opinion in Steps 4 and 5.

If the claimant doesn’t speak English, he or she should be tested in the native language using the SSA-recommended test or an equivalent test, if

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

available. If an acceptable speech recognition test is not available in the claimant’s native language, then a determination of disability will be made exclusively on the basis of the pure-tone threshold results. This could be perceived as unfair to persons who do not speak English well, since they would lose the chance to qualify on the basis of reduced speech recognition. According to the U.S. Census Bureau (2003) approximately 18 percent of the U.S. population speaks a language other than English in the home. Communication in some work environments also takes place in languages other than English. Thus, a priority for research is the development and validation of speech recognition tests in the most common languages other than English spoken in the United States that produce performance scores that are equivalent to those obtained on tests standardized in English. Individuals who cannot be tested reliably with standard behavioral techniques for pure-tone threshold assessment should be tested with auditory evoked potentials.

If an adult claimant wears a hearing aid or a cochlear implant, this must be noted on the checklist. Any claimant who wears a hearing aid must be evaluated in the unaided mode on the pure-tone threshold test and speech threshold test (described above) in addition to aided conditions for speech recognition testing (detailed below). Similarly, a claimant who wears a cochlear implant must be evaluated under earphones without the device, for the pure-tone threshold test and speech threshold test, and while wearing the device for the speech recognition tests.

CHECKLIST ITEM 8: Does the claimant wear a hearing aid, cochlear implant, or other device?

CHECKLIST ITEM 9: If yes, was the claimant using the hearing aid, cochlear implant, or other device during the speech recognition test?

In this case, the audiologist must determine how long the individual has used this device, the daily use of the device (hours/day), and if the individual has had a sufficient adjustment period to the device. The recommended adjustment period is at least 3 months for a hearing aid and 6 months for a cochlear implant. The audiologist also must measure the electroacoustic characteristics of the hearing aid following prevailing ANSI standards (American National Standards Institute, 2002c, 2002d, 2003b, or updated versions) and determine if the hearing aid is a reasonably optimal amplification system for this individual, in relation to the pure-tone thresholds and amplification targets derived from a hearing aid prescription. If the examining audiologist determines that the hearing aid is not a reasonably optimal fit for the claimant, it should be noted

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

in Checklist Item 11. The audiologist should not alter the device, but should proceed to aided testing with the hearing aid set to the claimant’s usual settings. However, the claimant should be encouraged to have the hearing aid adjusted by the fitting audiologist or the examining audiologist, and return for additional testing after a suitable period of adjustment. We strongly recommend that claimants who wear cochlear implants be evaluated at a center that programs cochlear implant devices and manages cochlear implant patients, to ensure that the cochlear implant map is appropriate for the patient at the time of the evaluation. If the claimant is tested at a cochlear implant center, then the audiologist should assess their map (t-levels and c-levels) and determine if the cochlear implant is operating adequately for this individual. If the evaluation does not take place at a cochlear implant center, then the audiologist should not make any adjustments to the device but should proceed to behavioral measures in the sound field. Several aided behavioral tests are recommended, in addition to those specified in the standard protocol, to ensure that the device is a reasonable fit for the claimant. These behavioral measures must be conducted with the hearing aid or cochlear implant adjusted to the claimant’s usual settings.

The additional testing with the claimant’s own device(s) consists of measures of signal detection in the sound field. Detection thresholds in the sound field are assessed differently with the two types of devices (hearing aids and cochlear implants), in accordance with current standards of care, although speech recognition measures are assessed identically. Behavioral measures obtained in the sound field for cochlear implant users include thresholds for frequency-modulated (warble-tone) stimuli and speech recognition scores in quiet and noise using the same stimuli and noises as recommended for unaided testing. A cochlear implant generally is considered to be working correctly if the electric thresholds to FM stimuli are 35-45 dB HL (assuming that electrode impedances are low and balanced and the battery is charged).

Sound field measures for hearing aid users are speech recognition thresholds and speech recognition scores in quiet and in noise. The recommended loudspeaker arrangement for sound field testing is for both target speech and background noise to be presented at 0° azimuth, to accommodate variations in monaural or binaural devices. Based on the behavioral and electroacoustic measures, the audiologist should complete checklist questions pertaining to the use and adequacy of the hearing aid or cochlear implant.

If a claimant does not use a hearing aid or a cochlear implant, he or she is tested in the unaided condition only. In some cases, the individual claimant will not wear a hearing aid or cochlear implant and the audiologist may determine that he or she can benefit from a hearing aid. Such a

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

person should be encouraged to obtain an appropriate device through the state department of vocational rehabilitation or through Medicaid, because the expense of a suitable hearing aid or cochlear implant may far exceed the resources of the claimant. If the claimant is able to obtain a suitable hearing aid or cochlear implant, then he or she should be retested for disability determination after receiving the device and having a sufficient opportunity to adjust to it. We recommend that the claimant be fully eligible to receive disability support on the basis of unaided testing until they receive and adjust to their hearing aid or cochlear implant.

CHECKLIST ITEM 10: Has the claimant been using a hearing aid or cochlear implant for a sufficient duration to derive maximum benefit from it (3 months for a hearing aid and 6 months for a cochlear implant)?

CHECKLIST ITEM 11: Answer both (a) and (b), based on your professional opinion:

(a) Has the claimant been tested with a reasonably optimal amplification system or cochlear implant?

(b) Is this person a candidate for either a hearing aid or a cochlear implant at this time?

For aided evaluation, the speech recognition criteria for disability determination are the same as those recommended for unaided assessment. Specifically, if an individual demonstrates aided performance that is 40 percent correct or poorer in quiet, then he or she qualifies for disability. If an individual does not qualify for disability on the basis of aided testing, then the claimant is not awarded benefits at Step 3 (based on meeting the medical listings), although evidence considered at Steps 4 and 5 may result in the awarding of benefits.

Some work environments are characterized by high noise levels. The Occupational Safety and Health Administration regulations require workers to use hearing protection if they work in environments with noise levels exceeding 90 dBA for an 8-hour day, to reduce the traumatic effects of noise on hearing. However, the requirement to wear hearing protection can make it more difficult for people with sensorineural hearing loss to function on the job. Knowledge about employment in industrial settings with high noise levels and the communication demands in the workplace may be useful for disability examiners and vocational experts in formulating disability decisions in Steps 4 and 5. The need to use hearing protection can make the work environment even more difficult for a worker who would benefit from hearing aids in other settings, and might affect the claimant’s ability to perform a particular job.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

CHECKLIST ITEM 12: Is the claimant required to use hearing protection on the job?

Table 4-3 presents a nonexhaustive set of descriptors of auditory tasks that may be encountered in the workplace. The current set of recommendations addresses many of these auditory tasks, but not all of them. Table entries include identification of those tasks addressed in the current protocol and formula, as well as those not addressed. The hearing-related tasks in the workplace that have not been addressed are those that should be evaluated in future research aimed at identifying the importance of these tasks in the workplace, as well as developing tests to measure performance on these tasks.

TABLE 4-3 Dimensions and Difficulty of Auditory Tasks in the Workplace in Relation to Clinical Tests Measured in the Standard Audiometric Protocol

Dimension

Easy

Addressed?

Difficult

Addressed?

Talker familiarity

Familiar talkers

No

Unfamiliar talkers

Yes

Phrase familiarity

Familiar job-related phrases

No

Novel phrases

Yes (assumed)

Talker gender

Adult male

No

Adult female

Yes

Speech level

Maximum level for highest score (PB-max)

No

Conversationallevel speech

Yes

Background noise

Quiet

Yes

Noise

Yes

Type of noise

Modulated

Yes

Steady-state

No

Energetic vs. informational masking noise

Energetic masking (no speech content)

No

Informational masking (speech content)

Yes

Number of background talkers

Single talker

Yes

Multiple talkers

No

Signal-to-noise ratio

Favorable (+10 dB)

Yes

Challenging (0 dB)

Yes

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

Dimension

Easy

Addressed?

Difficult

Addressed?

Spatial separation between target signal and background noise or speech

Large spatial separation

No

No spatial separation

Yes

Visual cues

Visual cues (in addition to auditory cues)

No

Auditory cues only

Yes

Number of talkers

One

Yes

Multiple talkers, switching

No

Location of talkers

Fixed

Yes

Variable

No

Reverberation

Short (< .2 sec RT)

Yes

Long (1.0 sec or more RT)

No

Task duration

Brief

Yes

Long (> 30 min)

No

Signal quality

Excellent

Yes

Distorted (public address systems)

No

Language familiarity

Native English

Yes

Nonnative English

Yes

Use of hearing aid

Test with hearing aid

Yes

Test without hearing aid

Yes

Use of cochlear implant

Test with cochlear implant

Yes

Test without cochlear implant

No (no measurable performance)

Signal detection

 

Yes

 

 

Discrimination of sound change

 

No

 

 

Localization

 

No

 

 

STEP-BY-STEP PROTOCOL

Action Recommendation 4-6. Presented below is a step-by-step out-line of the recommended protocol. Table 4-4 summarizes the criteria for disability based on performance on pure-tone audiometry and speech recognition tests. Box 4-1 (p. 114) presents a listing of all items required on the checklist, to be included with the results of audiometric testing.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

TABLE 4-4 Summary of Criteria for Hearing Disability

Test Procedure

Unaided Testing (for person who does not wear a hearing aid or cochlear implant)

Testing with Hearing Aid or Cochlear Implant

Pure tones

PTA 512 ≥ 90 dB HL in better ear and bone conduction at limits of equipment, OR

Not applicable

Speech recognition in quiet

≤ 40 percent at 70 dB SPL in sound field

≤ 40 percent at 70 dB SPL in sound field

Protocol for Person Who Doesn’t Use a Hearing Aid or Cochlear Implant

Audiologist:
  1. Assess pure-tone thresholds for each ear separately by air conduction under earphones and by bone conduction. Calculate PTA based on air conduction thresholds at 500, 1000, and 2000 Hz.2 Assess SRTs for each ear separately under earphones. Conduct tympanometry and measure acoustic reflex thresholds.

  2. Assess speech recognition performance for two full 50-item lists of monosyllabic words presented at 70 dB SPL in the sound field at 0° azimuth in quiet (speech recognition test: VA-NU6 recording or other equivalent tests approved by SSA subsequent to this report). Testing is binaural with ears uncovered. Calculate and report percentage-correct scores for each list individually and for the two lists combined. If the score in quiet is 0 percent correct, it is not necessary to continue testing in noise (Step 3).

  3. Assess speech recognition performance for one full 50-item list of monosyllabic words (VA-NU6) presented at 70 dB SPL in the sound field in competing message (single competing talker), at +10 dB S/N ratio. Both speech and noise are to be presented from a single loudspeaker located at 0° azimuth. Subsequently, assess speech recognition perfor

2  

If for any frequency the measured threshold is greater than 110 dB or if there is no response at the limit of the audiometer, a threshold value of 110 dB should be used for calculating the PTA.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

mance for one full 50-item list of monosyllabic words (VA-NU6) presented at 70 dB SPL in the sound field in competing message (single competing talker) at 0 dB S/N ratio. Both speech and noise are presented from a single loudspeaker located at 0° azimuth.

Social Security Administration:
  1. Determine if claimant qualifies on basis of medical listing:

Is PTA in the better ear ≥ 90 dB HL and bone conduction at the limits of the equipment → If yes qualifies.

or

Is speech recognition performance in quiet ≤ 40 percent correct?

If yes → qualifies.

If claim is denied based on Step 3 medical listing, go to Steps 4 and 5 and review speech recognition performance in noise, in relation to workplace environment.

Protocol for Person Using a Hearing Aid or Cochlear Implant

Audiologist:
  1. Conduct unaided testing, as above (pure tones for each ear separately by air conduction and SRTs for each ear separately under earphones, pure tones for bone conduction, tympanometry, acoustic reflex thresholds).

  2. Evaluate the electroacoustic characteristics of the hearing aid, the map of the cochlear implant, and aided/electric sound field thresholds for appropriate stimuli.

  3. Assess speech recognition performance for two full 50-item lists of monosyllabic words (total = 100 words) presented in the sound field in quiet at 0° azimuth, while claimant wears the hearing aid or cochlear implant, with the device adjusted to the user’s normal settings. Testing is binaural with unaided ear uncovered. The speech presentation level is 70 dB SPL. Determine and report percentage-correct recognition performance for each list separately and for the two lists combined (speech recognition test: VA-NU6 recording or equivalent). If claimant scores 0 percent, it is not necessary to continue testing in noise.

  4. Assess speech recognition performance in noise (single competing talker or other noise used with additional speech recognition tests ap-

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

proved by SSA subsequent to this report), with speech presented at 70 dB SPL and S/N ratio = +10 and 0 dB through a single loudspeaker located at 0° azimuth, while claimant wears the hearing aid or cochlear implant, with the device adjusted to the user’s normal settings. Testing is binaural (if there is an unaided ear, it should be uncovered). Determine percentage correct (speech recognition test is 50-item list of VA-NU6 recording or equivalent, using a different list in each condition from those used in 3 above).

Social Security Administration:
  1. Determine if claimant qualifies for disability.

If claimant scores ≤ 40 percent correct on speech recognition test in quiet → qualifies. If claimant doesn’t qualify, use data collected in noise for Steps 4 and 5 disability determination.

ADVICE AND RECOMMENDATIONS FOR STEPS 4 AND 5

Action Recommendation 4-7. The current protocol includes evaluation of speech recognition performance in noise, in addition to the existing tests of speech recognition performance in quiet and pure-tone hearing sensitivity, with the goal of assisting SSA officers in evaluating claims in Steps 4 and 5. The committee recommends that SSA should examine the claimant’s speech communication tasks on the job, in relation to performance on these audiological measures. The claimant should provide information about the communication and hearing requirements on their job. For example, the following communication requirements should be determined:

  1. Does the claimant work in a job in which there is auditory or speech communication, and in what language?

  2. Do most oral communication interactions occur in a quiet environment?

  3. Does the job require two-way speech communication on the telephone?

  4. Is oral communication in a moderately noisy environment (e.g., an office with coworkers talking)?

  5. Is oral communication in a highly noisy environment (e.g., a factory or a restaurant)?

  6. Is oral communication critical for life-threatening conditions in high noise levels (e.g., in firefighting or during a police action)?

  7. Are hearing protection devices required in the work environment?

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

The specific communication requirements on the job should then be linked to the auditory skills that the individual possesses by examining Table 4-2.

RECOMMENDATIONS FOR NEEDED RESEARCH

The review of procedures and materials for assessing speech recognition underscores the need for additional research in a number of topic areas, particularly for purposes of developing speech recognition tests that predict functional hearing ability in the workplace. The committee recommends that SSA collaborate with other agencies, such as the National Institutes of Health and the U.S. Department of Education, to support a number of research objectives in this area. The first set of research recommendations presented below identifies those with the highest priority according to the committee.

Research Recommendations with Highest Priority

Research Recommendation 4-1. Develop standardized speech recognition measures and procedures that correlate with functional hearing ability in the workplace. Any new speech tests must be validated as predictors of performance on everyday tasks in the workplace. Validation may include establishing the relationship between aided and unaided performance on newly developed standardized speech tests administered in controlled clinical settings, either to corresponding performance on everyday communication tasks in the workplace, or to self-report or reports of others (supervisors, family members, coworkers) about oral communication difficulties. This validation step is essential for adoption of any new speech tests for purposes of disability determination.

Research Recommendation 4-2. Develop sentence materials that permit assessment of performance in both quiet and noise. Tests that quantify performance with a metric that is readily interpreted (e.g., percentage correct) would be particularly useful. Evaluation of the test properties with selected background noises that simulate different listening environments and typical S/N ratios (e.g., Pearsons, Bennett, and Fidell, 1977) is essential for estimating everyday performance.

Research Recommendation 4-3. Evaluate recognition performance for speech materials presented at conversational speech levels in the sound field by a wide range of listeners, including those with varying degrees of hearing loss and those who use hearing aids and cochlear implants. These must also be known to quantify the effects of hearing loss and the use of assistive devices on speech understanding in conditions that simulate everyday listening.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

Research Recommendation 4-4. Assess basic auditory requirements of jobs, and how they relate to auditory measures that are available. This could be done on a job-specific basis, using an occupational taxonomy like O*Net, or could be based on some set of basic hearing functions.

Research Recommendations with Secondary Priority

Research Recommendation 4-5. Develop speech recognition tests in the most common languages other than English spoken in the United States, in order to evaluate nonnative speakers of English in a comprehensive assessment protocol comparable to that used with native speakers of English. Based on reports by the U.S. Census Bureau, 2003, the most common languages are Spanish (28 million speakers) and Chinese (2 million speakers), with French, German, Tagalog, Vietnamese, Korean, Russian, Polish, and Arabic also spoken by at least half a million residents each. The psychometric properties (performance-intensity functions, performance at varying S/N ratios, etc.) of these tests in a foreign language must be evaluated, as well as the validity of response formats that can be scored by audiologists unfamiliar with the test language.

Research Recommendation 4-6. Standardize video-recorded (VCR or DVD) sentence tests presented in unisensory and bisensory modalities. These would be particularly valuable to assess the extent to which the availability of visual cues aids speech reception in everyday listening situations by individuals with significant hearing loss. Normative evaluation of the psychometric properties of the materials presented in the unisensory (auditory) and bisensory (auditory + visual) modalities must be available before such tests could be adopted for use in disability determination.

Research Recommendation 4-7. Develop and validate methods to detect and manage exaggeration of speech recognition problems during administration of the speech tests, including comparison of AI/SII predictions to the observed score in quiet.

Research Recommendation 4-8. Evaluate the accuracy of the current Step 3 medical listing for hearing impairment that qualifies for disability. The committee recommends that SSA collect and analyze longitudinal data on documented earnings on claimants who fail to win eligibility over the next several years. (Such data are already available to the SSA.) All personal identifying information would be masked and the research design would be approved by the appropriate institutional review board. People who have no significant earnings from employment could be characterized as “false negatives” and people who have significant earnings would be “true negatives.” In addition, performance data for those who are granted benefits or who are medically eligible but do not receive

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
×

benefits could also be tracked. For all claimants, sound field testing should be performed (with hearing aids if the claimant has them), both in quiet and in noise, as part of the new recommended protocol. SSA could then analyze which of the hearing test measures (PTA, speech recognition performance in the sound field for VA-NU6 presented in quiet, speech recognition performance in the sound field for VA-NU6 in noise at two S/N ratios) predicted the outcome (false negative versus true negative). Conceivably, two or more variables could provide independent predictive power, justifying use of a composite variable in a new medical listing. If there is just one best predictor, SSA could then find the best new cutoff score by examining the marginal changes in the FN/TN ratio as the cutoff is varied.

Research Recommendation 4-9. Develop and validate clinical tests of localization for purposes of estimating everyday performance in real-world environments while listeners are unaided or use hearing aids or cochlear implants.

Research Recommendation 4-10. Develop and validate clinical tests of auditory discrimination for evaluating the ability to detect small changes in acoustic signals necessary for hearing-critical jobs.

Suggested Citation:"4 Testing Adult Hearing: Conclusions and Recommendations." National Research Council. 2005. Hearing Loss: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/11099.
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Millions of Americans experience some degree of hearing loss. The Social Security Administration (SSA) operates programs that provide cash disability benefits to people with permanent impairments like hearing loss, if they can show that their impairments meet stringent SSA criteria and their earnings are below an SSA threshold. The National Research Council convened an expert committee at the request of the SSA to study the issues related to disability determination for people with hearing loss. This volume is the product of that study.

Hearing Loss: Determining Eligibility for Social Security Benefits reviews current knowledge about hearing loss and its measurement and treatment, and provides an evaluation of the strengths and weaknesses of the current processes and criteria. It recommends changes to strengthen the disability determination process and ensure its reliability and fairness. The book addresses criteria for selection of pure tone and speech tests, guidelines for test administration, testing of hearing in noise, special issues related to testing children, and the difficulty of predicting work capacity from clinical hearing test results. It should be useful to audiologists, otolaryngologists, disability advocates, and others who are concerned with people who have hearing loss.

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