Summary

The U.S. Social Security Administration (SSA) administers the Social Security Disability Insurance (SSDI) program and the Supplemental Security Income (SSI) program. Those programs provide disability benefits to individuals who qualify due to a disability. Once SSA establishes the presence of a severe medically determinable impairment, it determines whether the impairment meets or equals the criteria in the Listing of Impairments (the Listings), which are lists of medical conditions that qualify a candidate for disability benefits regardless of the applicant’s age, education, or work experience. If an individual does not meet Listings-level criteria, they can still qualify for disability further along in the sequential evaluation process based on “residual functional capacity,” or functional limitations resulting from their medical impairments. The Listings are organized into 14 body systems for adults and 15 body systems for children. Special senses-related disorders that affect the ability to hear are evaluated under SSA Listings 2.00 for adults and Listings 102.00 for children. SSA organizes the evaluation of hearing loss into two broad categories: hearing loss not treated with cochlear implantation and hearing loss treated with cochlear implantation. The focus of this report is hearing loss in adults and children treated with cochlear implantation.

The current Listings that address hearing loss treated with cochlear implantation (2.11 and 102.11) contain criteria that evaluate hearing ability through a word recognition score determined using the Hearing in Noise Test (HINT) performed in a quiet sound field. To be used in SSA’s program, HINT testing must be performed on a person with properly functioning cochlear implants set at normal settings, with no visual testing cues, in a

quiet sound field and at 60 dB HL (decibels in hearing level). SSA seeks to generalize the Listings criteria found in 2.11B and 102.11B (of Subpart P of Part 404, Listing of Impairments) so that the criteria can be evaluated with the results from hearing tests other than the HINT but with similar levels of validity, specificity, sensitivity, and reliability. Unlike the Listing for hearing loss in individuals with cochlear implants, the Listing for hearing loss not treated with cochlear implantation (2.10 and 102.10) does not specify a test (i.e., the HINT). Instead, it requires a “word recognition score of 40 percent or less in the better ear determined using a standardized list of phonetically balanced monosyllabic words.”

STATEMENT OF TASK

SSA has requested that a consensus committee of the National Academies of Sciences, Engineering, and Medicine identify and recommend generalized testing procedures and criteria for evaluating the level of functional hearing ability needed to make a disability determination in adults and children after cochlear implantation. The committee will produce a report detailing and supporting their findings, conclusions, and recommendations based on published evidence (to the extent possible) and professional judgment (where published evidence is lacking). The committee will:

1. Identify and describe the salient test characteristics of the HINT, which is currently used to determine the functional hearing ability in adults or children with hearing loss treated with cochlear implantation, and provide recommendations as to how to generalize those characteristics into criteria that can be applied to other validated hearing tests for persons with cochlear implants.
2. Describe the characteristics of hearing tests, administered in the sound field, either binaurally or monaurally, in either quiet or noise, that are in use for those with cochlear implants, and describe to the degree possible:
   1. The availability of the selected tests with respect to the instruments themselves, trained administrators of the tests, and insurance coverage or costs incurred with testing;
   2. The patient burden of undergoing these tests;
   3. Whether testing procedures or parameters, or the appropriateness of the test itself, vary based on the age of the person being tested;
   4. Whether the test outcomes are expected to vary based on demographic or other patient characteristic factors, including repeated testing with the same instrument; and

2. 5. The validity, specificity, sensitivity, reliability, and generalizability of the tests.
3. Among the hearing tests described in task 2, identify those with characteristics most similar to the HINT, determine which tests, performed in the sound field, either binaurally or monaurally, in either quiet or noise, produce measurements most closely analogous to the word recognition score of the HINT (given HINT testing parameters of properly functioning cochlear implants set at normal settings, with no visual testing cues, in a quiet sound field, at 60 dB HL), and describe to the degree possible:
   1. What differences exist between the identified tests and the HINT in terms of the specific elements of hearing ability they measure;
   2. The committee’s recommendations as to how scores from the identified tests can be compared or converted to equivalent scores on the HINT; and
   3. The committee’s recommendations for the scores on hearing tests that correspond to a level of functional hearing ability that causes marked and severe functional limitation in a child or that prevents an adult from doing any gainful activity, regardless of his or her age, education, or work experience, and whether those scores can be expressed in a form comparable between hearing tests such as percentile or standard deviation from the norm.
4. Examine the special considerations inherent in evaluating hearing ability in persons with single-sided deafness or asymmetric hearing loss receiving a cochlear implant and describe:
   1. Any special considerations in the testing and treatment of persons with bilateral but unequal hearing loss;
   2. Whether there is a correlation between the presence and degree of hearing loss in the less-affected ear and the recovery time or treatment for individuals with single-sided deafness or asymmetric hearing loss receiving a cochlear implant in their more-affected ear;
   3. Whether there is a level of hearing ability in the less-affected ear which would render cochlear implantation in the more-affected ear immaterial with respect to meeting the severity of hearing loss in the Listings (i.e., would not prevent an adult from engaging in any gainful activity nor a child from having “marked” limitations in two domains of functioning or an “extreme” limitation in one domain);
   4. Whether the tests identified in task 3 remain appropriate for testing hearing ability in persons with single-sided deafness

1. 4. or asymmetric hearing loss receiving a cochlear implant and why, and if there are any differences in how the tests should be administered or interpreted; and
   5. Whether the equivalent scores identified in task 3 remain accurate proxies for the HINT word recognition scores when assessing persons with single-sided deafness or asymmetric hearing loss receiving a cochlear implant.

In its discussion with SSA, the committee interpreted its charge to provide SSA with a recommendation for tests that would be accessible and feasible for widespread use by audiology clinics, and that would align with standard clinical practice.

COCHLEAR IMPLANTS

Cochlear implants are small electronic devices that help provide a sense of sound to profoundly deaf or severely hard-of-hearing individuals. They function differently from hearing aids, as implants do not amplify sounds to improve normal hearing; instead, they give a person a representation of sounds in the environment, which in turn helps with understanding speech. Cochlear implants are surgically implanted and work by replacing the function of the damaged cochlea (inner ear) and stimulating the auditory nerve directly. The most recently published data from the National Institute on Deafness and Other Communication Disorders state that in 2012 approximately 58,000 adults and 38,000 children in the United States were reported to have cochlear implants. However, due to the expansion of indications and implantations in the past decade, those numbers are now a significant under-estimate. The American Cochlear Implant Alliance estimates that there were a total of 217,000 cochlear implant users in the United States in 2019. That number is based on a 9 percent annual growth rate from 2012.

In early clinical trials, to qualify for cochlear implants, adults were required to score 0 percent on open-set measures of sentence recognition, and children were required to demonstrate bilateral profound sensorineural hearing loss, as the outcomes with cochlear implants were unknown. As the safety and efficacy of cochlear implants became known, the criteria to receive a cochlear implant changed. Traditionally, most devices based candidacy on a sentence score for adults and on a word score for children. However, in 2019 the U.S. Food and Drug Administration (FDA) approved the MED-EL devices for use in children (5 years of age and older) and adults with single-sided deafness (SSD) and asymmetric hearing loss (AHL). Both approvals include indications that base candidacy on a word score for both children and adults and represent a trend toward the use

of monosyllabic word measures with both children and adults in the field of cochlear implants. From 2000 to early 2020, cochlear implants were FDA-approved for use in children beginning at 12 months of age; however, in March 2020, Cochlear Ltd. (Sydney, Australia) received FDA approval to expand the labeled indications from 12 to 9 months of age. For young children who are deaf or severely hard-of-hearing, using a cochlear implant exposes them to sounds during an optimal period for developing auditory speech and language skills. There is a growing body of literature demonstrating that children who receive cochlear implants before 12 months of age significantly outperform children who are implanted between 12 and 18 months on measures of language development, speech perception, and vocabulary as well as speech intelligibility (i.e., how well others are able to understand one’s speech).

THE HEARING IN NOISE TEST

The HINT, first published in 1994, is the test that SSA currently uses to determine functional hearing ability in adults or children with hearing loss treated with cochlear implantation. The HINT measures sentence recognition and is standardized to be administered with background noise, although SSA uses the HINT sentences in a quiet sound field. The HINT corpus is composed of 250 sentences, which are categorized into 25 lists. The sentences for the HINT were adapted from 336 Bamford-Kowal-Bench (BKB) sentences written in British English to American English sentences of equivalent content and length. During the test, the subject uses both ears (binaural hearing) and is required to repeat sentences in a quiet environment and with competing noise presented from different directions.

The volume of each sentence is adjusted based on listener response. Following each correct response, the volume is decreased, which increases the level of difficulty for the next sentence on the list. After an incorrect response the volume is increased, which reduces the difficulty for hearing each subsequent sentence. The level of background noise is held constant.

The HINT was developed in 1994 to be adaptively measured (i.e., the signal-to-noise ratio was adjusted between trials according to whether the response was correct) in order to minimize floor and ceiling effects.¹ However, clinical use of the HINT does not incorporate adaptive administration; rather, the sentences are typically presented at a fixed level “in quiet,” that is, in a quiet environment. This, along with improvements in cochlear implant technology, has resulted in individuals with cochlear implants scoring consistently near the ceiling on the HINT. Unilateral cochlear implant

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¹ A ceiling effect occurs when the items on a test are so easy that most people would achieve or be close to the highest possible score.

recipients with post-lingual onset of deafness are routinely achieving 60 percent open-set word recognition, on average. Indeed, an increasingly higher proportion of adult and pediatric cochlear implant recipients demonstrate at or near ceiling-level performance for sentence recognition in quiet.

Despite its common inclusion in cochlear implant candidacy and outcomes criteria for cochlear implant recipients, recent work has demonstrated that the HINT is limited not just by its ceiling effects when presented in quiet or fixed signal-to-noise ratios, but also by its administration, its ecologic validity, and its availability.

In particular, the lack of availability of the HINT materials has created various problems. When the Minimum Speech Test Battery (MSTB) was first conceptualized in 1996, cochlear implant surgery was performed only at select major medical centers in the United States. Those centers were able to obtain necessary test materials and had the appropriate equipment set up to perform speech performance assessments. However, due to the HINT’s exclusion from the most recent MSTB and because it is no longer available for purchase, the HINT is difficult for clinics across the United States to obtain.

As requested in the Statement of Task, the committee describes salient characteristics of the HINT. A summary is provided below in Table S-1.

CHARACTERISTICS OF SELECTED SENTENCE AND WORD TESTS

Chapter 4 provides an overview of characteristics of selected speech tests that are commonly used to evaluate hearing loss in adults and children with cochlear implants, in addition to the HINT. Table S-2 briefly summarizes those tests and their reliability or other salient characteristics. With the exception of the HINT and the Digit Triplet test, the tests presented in Table S-2 are readily available for purchase in the United States.

TESTING HEARING ABILITY IN PERSONS WITH SINGLE-SIDED DEAFNESS OR ASYMMETRIC HEARING LOSS RECEIVING A COCHLEAR IMPLANT

Historically, indications to qualify for a cochlear implant and indications to qualify for disability due to hearing loss have required patients to have significant bilateral hearing loss. With cochlear implants, this was a decision made in early clinical trials when the safety and efficacy of cochlear implants were not yet proven. The decision to provide cochlear implants to patients with significant SSD or AHL was made only recently in 2019,

TABLE S-1 Salient Characteristics of the Hearing in Noise Test (HINT)

^a The intended use may not be consistent with actual use due to fixed-presentation recommendations from the Minimum Speech Test Battery in 1996.

^b The clinician presenting the materials must be fluent in the language of administration.

when FDA approved cochlear implants for adults and children (ages 5 and up) with SSD and AHL. This decision was based on research demonstrating that most individuals with SSD or AHL demonstrated improvements in word and sentence recognition in quiet in the implanted ear, improvements in sentence recognition in noise when noise was presented to the better hearing ear, improvements in sound localization, and improvements in self-perceived quality of hearing.

The presence of bilateral profound hearing loss not treated with a cochlear implant will prevent adults from engaging in any gainful activity and will result in children having marked limitations in various domains of functioning. Currently, adult patients without a cochlear implant meet the criteria in the Listings if they demonstrate an average air conduction hearing threshold of 90 dB or greater in the better ear and an average bone conduction hearing threshold of 60 dB or greater in the better ear (2.10A), or if they demonstrate a word recognition score of 40 percent correct or

TABLE S-2 Reliability and Other Notable Characteristics of Selected Sentence and Word Tests

less in the better ear determined using a standardized list of phonetically balanced monosyllabic words (2.10B). Thus, patients’ hearing loss must be bilateral and must have a significant impact on their ability to communicate. If an adult patient’s hearing loss has been treated with a cochlear implant, he/she is considered disabled for 1 year after initial implantation (2.11A). On occasion, adults and children will continue to demonstrate difficulty hearing even after they receive a cochlear implant. When this occurs, they can still qualify for disability if they demonstrate a word recognition score of 60 percent correct or less determined using the HINT Sentences test (2.11B, 102.11). Most adults and children with bilateral significant hearing loss who receive a cochlear implant derive benefit from the device, and the improvements they receive often prevent them from qualifying for disability after 1 year of using the device.

As indicated previously, cochlear implants were not yet approved by FDA for use in patients with SSD or AHL when the current SSA guidelines were developed. Prior to approval of cochlear implants for SSD and AHL, indications for cochlear implants, like indications for disability, were based on the “best” hearing situation. Thus, most cochlear implant recipients who were implanted previously qualified for disability under both 2.10 and 2.11 prior to receiving a cochlear implant as they likely experienced significant hearing loss in each ear. That would not be the case for patients who currently receive a cochlear implant due to SSD or AHL because they possess normal or near-normal hearing in their better ear.

Under current SSA guidelines, patients with SSD or AHL automatically qualify for disability for a period of 1 year following cochlear implantation, with no consideration given to the hearing in their better ear. To remain consistent with the wording and rationale used in current guidelines for hearing loss not treated with cochlear implantation (Listings 2.10 and 102.10), it is reasonable to consider the hearing in the better ear when determining whether a patient with a cochlear implant qualifies for disability due to hearing loss after he/she receives a cochlear implant.

CONCLUSIONS AND RECOMMENDATIONS

Since its development in 1994, the HINT has been widely used to measure cochlear implant candidacy and post-operative outcomes. However, the test characteristics, the state of cochlear implant technology, and the environment that made the HINT a common choice of assessment in 1994 are different in 2021. The HINT has several limitations in its characteristics and deviation from its intended use. The MSTB recommendations note that “advances in technology, improvements in outcomes, and changes in candidacy criteria have resulted in ceiling effects on the HINT sentences

when presented in quiet.” FDA usage in effectiveness studies and unclear candidacy criteria from insurance providers (e.g., the Centers for Medicare & Medicaid Services) add to the limitations of the test. Finally, due to its exclusion from the most recent MSTB and the fact that it is no longer available for purchase, the HINT is difficult for clinics across the United States to obtain.

More recently, word recognition testing—which includes the administration of a phonemically balanced word list such as the Northwestern University Auditory Test Number 6, Central Institute for the Deaf W-22, or the Maryland consonant–nucleus–consonant word lists—has come to be employed in most audiology clinics. Monosyllabic word recognition is also currently the standard for pediatric cochlear implant candidacy, and the field is moving toward use of a monosyllabic word recognition criterion for determining adult candidacy in the United States. Additionally, for more than two decades monosyllabic word recognition has been used to characterize post-operative outcomes for both adult and pediatric cochlear implant recipients. Furthermore, SSA has been using monosyllabic words to determine initial and continued eligibility for SSA benefits for individuals with hearing loss who have not been treated with cochlear implantation.

The committee was tasked with recommending how scores from the identified tests can be compared with or converted to equivalent scores on the HINT. However, given the committee’s concerns with the utility of the HINT and limitations such as ceiling effects and lack of availability, deriving equivalent scores on the HINT would produce scores with limited interpretability. Additionally, while it may be of value to have a common metric or a conversion equivalent in the presence of newer tests, this task is complicated by a lack of large research studies with head-to-head comparisons of the HINT to other tests. Thus, the committee was unable to calculate meaningful equivalent test scores for the HINT.

The current use of the HINT sentences as criteria for cochlear implantation likely suffers from ceiling effects of the test materials, given improvements in modern cochlear implant technology and a lack of availability of test materials. Research may support an update of assessment of cochlear implementation via different materials. Speech assessment via sentences fundamentally differs from assessment via individual words because it offers context to the information, and such context may result in improved scores in speech understanding. Thus, given the difficulty of obtaining the HINT, the shift in the cochlear implant community toward using word tests, and the fact that SSA already uses word tests for individuals with hearing loss who do not have a cochlear implant, the committee makes the following recommendation:

As of this writing, examples of tests that meet those criteria and that are commonly used by audiologists to evaluate hearing loss in people with cochlear implants include the consonant–nucleus–consonant words or the Northwestern University Test No. 6 for adults and the Phonetically Balanced Kindergarten or Lexical Neighborhood Test for children.

SSA also asked the committee whether the tests identified in task 3 remain appropriate for testing hearing ability in persons with single-sided deafness or asymmetric hearing loss receiving a cochlear implant and why, and if there are any differences in how the tests should be administered or interpreted. The committee notes that the same tests and testing parameters can be used, with a few additional considerations. Testing for disability for hearing loss has typically focused on the test results obtained with the better ear. Thus, a patient who receives a cochlear implant due to SSD or AHL should be required to participate in testing that represents the listening situation that he/she uses on a daily basis, which typically includes an un-occluded better ear and an ear using hearing technology. Alternatively, it could be based on the individual being required to meet current requirements for hearing loss not treated with cochlear implantation in the ear not treated with a cochlear implant (Listing 2.10 and 102.10).

The Statement of Task requests that the committee “identify and recommend generalized testing procedures and criteria for evaluating the level of functional hearing ability needed to make a disability determination in adults and children after cochlear implantation.” Thus, based on standard clinical practice and the committee’s professional judgment:

Finally, the Statement of Task asks the committee

In response, the committee suggests that SSA use the same cut-off criteria for evaluating hearing loss in individuals with cochlear implants as the current Listing for hearing loss in individuals without cochlear implants. That cut-off aligns with the criteria used in the most recent FDA clinical trials for cochlear implants. Specifically, FDA trials use a cut-off score of 40 percent correct or less in the ear to be implanted and 50 percent correct or less in the contralateral ear on a recorded monosyllabic word test presented at 60 A-weighted dB (dB A).

The committee’s recommendation would allow SSA to provide a singular speech recognition measure and criterion across all individuals, irrespective of hearing technology. Given that cochlear implants are currently the final step on the hearing health care continuum, the committee believes that should an individual with a cochlear implant continue to meet the criteria for cochlear implantation after they have been implanted with their device, they clearly have demonstrated that the cochlear implant has not provided significant benefit. As such, the cochlear implant recipient most likely has a disability related to hearing loss.

No single test can fully capture the broad neurological faculties that allow for speech and language understanding. Speech perception tests assess a diverse set of abilities, and each provides different insight into specific auditory and processing capabilities. As a single measure, monosyllabic

word tests cannot capture the full auditory and communication profile of a listener, but the committee believes that it is a good proxy. The use of monosyllabic words does not penalize or reward a listener for being adept at top-down processing. Furthermore, the use of monosyllabic words is consistent with current clinical speech audiometry practice and is readily accessible. While it was not within the committee’s scope of work, the committee notes as a consideration that additional information from self-report or parent-report questionnaires may be useful in better characterizing an individual’s real-world communicative functioning. To fully evaluate auditory function, it can be helpful to include a subjective perspective from the patient or from their parent. Self-report or parent-report measurements, when used as a supplement to auditory threshold and speech testing, can help capture the complete picture of the impact of hearing loss in a given individual.

As a final note, the above recommendations were made based on the state of knowledge available to committee members at the time of writing. As advances in clinical practice, assessment measures, and hearing technology emerge, it is possible that better measures for assessing significant disability will become available. Therefore, should more information become known in the future, it may be necessary to revisit the recommendations in this report.