Much attention is given to those of us who are diagnosed and treated for hearing loss. And, strong education programs are working to get undiagnosed people with hearing loss to a local hearing health professional for assistance with their hearing. But what about the over 25 million adults in the United States that have been tested for hearing loss with results that fall “Within Normal Limits” but still complain of hearing difficulty or speech in noise detection. Unfortunately, the benefits of hearing aids or other assistive listening technology are not presented to them in traditional hearing evaluations because their hearing is considered within the normal range.
However, the benefits of using assistive devices can produce tangible increases in the quality of hearing and distinguishing speech in noisy environments for this segment of the population. A group of researchers gathered statistical data and presented evidence on the benefits of hearing assistive devices in the October 2018 issue of Hearing Review.
The reviewed data indicated that there is much more depth and nuance to hearing evaluation than what standardized tests are currently capturing. Using self-report assessments such as the Client Oriented Scale of Improvement (COSI) or the Hearing Handicap Inventory for Adults (HHIA), the incidents of self-reported hearing difficulty and speech in noise detection was 37% to 43% higher than reported on conventional assessment tests.
These self-assessment tools are commonly used on patients that have a diagnosed hearing loss, but less so on people whose hearing falls within normal ranges.
A New Perspective On Hearing
The classification of “normal” hearing is often misleading since it uses fairly narrow parameters to make that determination, without taking the full picture into perspective. While audiologists may not want to throw the baby out with the bathwater, they may want to consider adding official classifications such as “hearing sensitivity within the range of normal limits” when referring to “normal” hearing based on audiometric measurements.
This may help broaden the conditions that qualify or warrant additional evaluation to assess the need for specific assistive listening devices in situations where “normal” hearers have difficulty hearing.
There may be some hidden factors that explain why individuals whose hearing falls within normal limits still complain of hearing difficulty or speech in noise detection difficulty.
One theory is that standard hearing evaluations are not sensitive enough to detect hidden hearing loss (HHL) or Cochlear Synaptopathy (CS), which can reduce neural output from the cochlea.
Another theory takes extended high-frequency hearing loss into consideration, a problem that directly relates to speech in noise difficulty.
Auditory Processing Disorders (APD) is a controversial term that indicates difficulty processing speech in noise. No diagnosis method has been identified for this condition.
Auditory Neuropathy Spectrum Disorder (ANSD) is often missed by conventional hearing assessments. Individuals with ANSD have dyssynchronous firing of the auditory nerve fibers, resulting in abnormal speech resolution and difficulty with speech intelligibility.
Administering Testing For Speech-In-Noise
A Speech-in-noise test is an effective way to evaluate and address complaints of hearing difficulty in individuals with “normal” hearing. It is also effective for individuals who have diagnosed hearing loss. Yet, less than 15% of audiologists use this test.
This and similar tests are crucial to the future identification of hearing difficulties in all forms.