The Role of the Clinically Obtained Acoustic Reflex as a Research Tool for Subclinical Hearing Pathologies.
Andrew Causon, Kevin J Munro, Christopher J Plack and 1 others
PMID 33357018WHAT IT FOUND
The clinical acoustic reflex test did not detect subclinical hearing damage from noise exposure in young adults with normal hearing.
Reflex strength varied significantly with middle-ear compliance and sex, making it unreliable as a standalone measure of hidden hearing loss.
Key findings
01Acoustic reflex threshold and growth showed no significant correlation with estimated lifetime noise exposure.
02Middle-ear compliance significantly predicted acoustic reflex growth, with males showing higher compliance and steeper reflex growth than females.
03Ipsilateral and contralateral acoustic reflex measurements were not strongly predictive of each other, meaning the choice of testing method significantly alters the result.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study used a standard clinical 226 Hz probe tone; wideband systems might detect changes this method misses. The cohort had limited numbers of people with very high noise exposure, so it may not detect damage in those with extreme histories. Only the right ear was tested, assuming it represented the better ear, which may not hold for all participants. The study was preregistered but the specific curve-fitting method was not defined initially, leading to a post-hoc decision to use linear regression.
Declared interests
One author works for a medical device company in auditory prostheses, but this role began after the data collection and analysis. The study was funded by the Medical Research Council and NIHR Manchester.
The easy way to misread this
Do not interpret the lack of correlation with noise exposure as proof that acoustic reflexes are useless in all contexts. The study only shows that the *standard clinical protocol* is not sensitive enough to detect subclinical noise damage in this specific group of young adults with normal hearing.