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Hearing Loss: Determining Eligibility for Social Security Benefits 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).
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Hearing Loss: Determining Eligibility for Social Security Benefits 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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: 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; 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; Jobs that require frequent conversation with strangers about unfamiliar topics, often without the aid of vision (for example, on the telephone); 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.
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Hearing Loss: Determining Eligibility for Social Security Benefits 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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-
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Hearing Loss: Determining Eligibility for Social Security Benefits 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: 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). 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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.
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Hearing Loss: Determining Eligibility for Social Security Benefits 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-
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Hearing Loss: Determining Eligibility for Social Security Benefits 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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.
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Hearing Loss: Determining Eligibility for Social Security Benefits 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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.
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Hearing Loss: Determining Eligibility for Social Security Benefits 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: 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. 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). 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.
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Hearing Loss: Determining Eligibility for Social Security Benefits 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: 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: 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). Evaluate the electroacoustic characteristics of the hearing aid, the map of the cochlear implant, and aided/electric sound field thresholds for appropriate stimuli. 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. Assess speech recognition performance in noise (single competing talker or other noise used with additional speech recognition tests ap-
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Hearing Loss: Determining Eligibility for Social Security Benefits 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: 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: Does the claimant work in a job in which there is auditory or speech communication, and in what language? Do most oral communication interactions occur in a quiet environment? Does the job require two-way speech communication on the telephone? Is oral communication in a moderately noisy environment (e.g., an office with coworkers talking)? Is oral communication in a highly noisy environment (e.g., a factory or a restaurant)? Is oral communication critical for life-threatening conditions in high noise levels (e.g., in firefighting or during a police action)? Are hearing protection devices required in the work environment?
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Hearing Loss: Determining Eligibility for Social Security Benefits 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.
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Hearing Loss: Determining Eligibility for Social Security Benefits 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
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Hearing Loss: Determining Eligibility for Social Security Benefits 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.
Representative terms from entire chapter: