April 2021 The Hearing Journal
The Social Security Administration (SSA) should use a monosyllabic word recognition test to evaluate the hearing ability of people with cochlear implants (CIs), recommends a special committee convened by the National Academies of Sciences, Engineering, and Medicine in a recent report, Evaluating Hearing Loss for Individuals with Cochlear Implants. The report was requested by the SSA as the agency seeks to generalise its Listings criteria for hearing loss disability determination.
Currently, the SSA uses the Hearing in Noise Test (HINT) to measure sentence recognition of individuals who have CIs, as part of a screening procedure for qualifying for disability benefits. However, the committee found that the HINT has limitations that should prompt a change in the testing procedure. According to the report, the HINT is limited by its “ceiling effects," referring to the consistently high scores that people with Cis now achieve on the test primarily due to advancements in CI technology and the fact that the examination is often administered in a quiet environment. The report also pointed out that the HINT is no longer commercially available and has become difficult for clinics to obtain.
ENSURING STANDARDIZED TESTING
To update the SSA's hearing evaluation of post-implantation hearing, the committee recommended a monosyllabic word recognition test, as opposed to the sentence recognition measured by the HINT. The SSA already uses word tests to evaluate hearing in individuals who do not have a cochlear implant. The recommended post-implantation test should have the following characteristics:
- It should be conducted with a full word list that is standardised and phonetically or phonemically balanced.
- 60 dB SPL using hearing technology recommended for the individual that is functioning properly and adjusted to the individual's normal settings. In cases of single-sided deafness or asymmetric hearing loss, the non-implanted ear should not be occluded for testing.
- The level should be calibrated for sound field presentation.
- The test material should be recorded to ensure standardised administration;
- Testing should occur in quiet in a sound-treated booth; and
- The listener should be seated one meter from the loudspeaker at 0-degree azimuth.
A cut-off score of 40% or less on a monosyllabic word would be used. This is the same cut-off that the SSA currently uses for the word recognition scores of individuals with hearing loss but without CIs.
“Because this is an accepted criterion for determining disability status for individuals with hearing loss, the committee felt it was reasonable to use the same criterion for all individuals with hearing loss—irrespective of their hearing technology," said René H. Gifford, PhD, CCC-A, committee member and the director of the Cochlear Implant Program at the Vanderbilt Bill Wilkerson Center as well as the associate director of Implantable Hearing Technologies.
Standardised monosyllabic word assessments, she noted, are easily accessible and routinely used at diagnostic audiology clinics. “Furthermore, the fields of Audiology and Otology are moving toward CI candidacy determination based on monosyllabic word recognition performance," Gifford told The Hearing Journal. “In fact, two of the three CI manufacturers have completed FDA-regulated clinical trials investigating a revised indication for adult CI candidacy including individuals scoring up to 40 percent aided word recognition. Thus, there was not only a precedent for the existing SSA criterion for hearing-related disability determination and wide availability and familiarity of monosyllabic word tests, but there is also supporting evidence that this level of speech recognition performance is consistent with severe communication difficulty rendering a listener a CI candidate”.
In summary, the committee agreed that should an individual continue to meet criteria for a CI following cochlear implantation—scoring less than 40 percent for aided monosyllabic word recognition—this would certainly be consistent with a hearing-related disability.
MEASURING FUNCTIONAL HEARING
It may be noted that the report advised not to occlude the non-implanted ear when testing for asymmetric hearing loss. This differs from the typical procedure for determining implant candidacy, which occludes the better ear. “These recommendations are not relevant for determining candidacy for cochlear implantation," clarified Gifford. “All committee members expressed complete support for ear-specific testing for CI candidacy determination, but our charge was focused exclusively on disability. With respect to disability, the SSA has always considered how an individual can function in everyday living conditions. CI recipients with single-sided deafness use both their CI and their better-hearing ear for everyday communication and are evaluated in that listening configuration.”