The Impacts of Noise Exposure on the Middle Ear Muscle Reflex in a Veteran Population.
Naomi F Bramhall, Kelly M Reavis, M Patrick Feeney and 1 others
PMID 35050699WHAT IT FOUND
Veterans with high noise exposure showed weaker middle ear reflexes than controls, but the difference did not reach statistical significance.
The reflex measure was not correlated with other brainstem responses, suggesting it may track different nerve fibers.
Key findings
01Veterans with high noise exposure had a modeled 25% reduction in middle ear muscle reflex magnitude compared to non-Veteran controls, but the confidence interval overlapped zero.
02Middle ear muscle reflex magnitude was not significantly correlated with auditory brainstem response wave I amplitude or envelope following response magnitude.
03Subclinical outer hair cell dysfunction did not appear to impact middle ear muscle reflex magnitude, supporting its potential use in individuals with mild hearing loss.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The primary finding of reduced MEMR magnitude in high-noise veterans was not statistically significant. The study relied on self-reported noise exposure history, which may be subject to recall bias. MEMR cannot distinguish between synapse loss and other types of cochlear deafferentation. The sample size was relatively small, particularly for the Veteran groups. Veterans with high noise exposure were predominantly male, which may limit generalizability across sexes.
Declared interests
The study was supported by the Department of Veterans Affairs Rehabilitation Research and Development Service and the National Institute on Deafness and Other Communication Disorders. No specific commercial conflicts of interest were reported in the provided text.
The easy way to misread this
Do not assume that a normal middle ear muscle reflex rules out noise-induced synaptopathy. The study found that MEMR magnitude did not correlate with ABR wave I amplitude or EFR magnitude, suggesting these tests may measure different aspects of auditory nerve function.