Tinnitus and Auditory Perception After a History of Noise Exposure: Relationship to Auditory Brainstem Response Measures.
Naomi F Bramhall, Dawn Konrad-Martin, Garnett P McMillan
PMID 29337762WHAT IT FOUND
In young adults with normal hearing, a lower early auditory brainstem response wave was associated with reported tinnitus.
It was not associated with speech perception in quiet or noise, or loudness discomfort. This is an association, not a diagnostic test.
Key findings
01Lower ABR wave I amplitude was associated with reported tinnitus, and the association remained after adjusting for sex and DPOAE level.
02ABR wave I amplitude was not associated with speech perception in quiet, speech-in-noise performance, or loudness discomfort levels.
03Among people with normal hearing, tinnitus was reported by 82% of Veterans with high noise exposure, 7% of Veterans with lower noise exposure, and 0% of the two non-Veteran groups.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study was cross-sectional, so it cannot show that lower wave I amplitude caused tinnitus or that tinnitus began after noise exposure. Cochlear synaptopathy could not be confirmed because there was no temporal bone analysis, and wave I amplitude is an indirect measure of auditory nerve activity. Wave I amplitude varied too much between individuals to diagnose synaptopathy or tinnitus in one patient. The sample was small, especially for females with tinnitus; only 2 female Veterans with high noise exposure were available, and only 2 female participants reported tinnitus in the test ear. Loudness discomfort level alone may not reliably measure hyperacusis, so the null result for loudness discomfort levels does not settle whether hyperacusis is related to wave I amplitude. The speech-in-noise test used was the WIN test, and the authors note that other or more difficult speech tests may be needed to detect noise-related effects. Extended high-frequency thresholds were not obtained for 3 participants with tinnitus and 15 participants without tinnitus, and DPOAE screening may not detect all outer hair cell damage.
The easy way to misread this
Do not read the wave I amplitude association as proof of cochlear synaptopathy or as a way to diagnose tinnitus in an individual patient. The study was cross-sectional, synaptopathy could not be confirmed without temporal bone analysis, and individual wave I amplitude variability was too large for single-patient diagnosis.