Low-level otoacoustic emissions may predict susceptibility to noise-induced hearing loss

Judi Lapsley Miller, Lynne Marshall, Laurie Heller, & Linda Hughes

Journal of the Acoustical Society of America, 120(1), 280-296.

Abstract

Transient-evoked otoacoustic emissions (TEOAEs), distortion-product otoacoustic emissions (DPOAEs), and pure-tone hearing thresholds were measured in 338 sailors before and after a six-month deployment on an aircraft carrier. Repeated-measures ANOVA indicated that hearing thresholds did not shift after deployment, but that OAE amplitudes decreased, indicating sensitivity to noise-induced changes in the inner ear. Correlations between OAE amplitude shifts and hearing threshold shifts indicated that OAEs and hearing thresholds did not shift together. DPOAEs and TEOAEs shifted concurrently, although the association was only moderate. Eighteen ears (fifteen sailors) had permanent threshold shifts (PTS) post-deployment. While only one-third of PTS ears showed significant OAE shifts that mirrored the PTS, 75% had at least one low-level or absent OAE at pre-deployment. Using a Bayesian analysis, post-deployment PTS was predicted by pre-deployment low-level or absent OAEs. The best predictor was pre-deployment TEOAE amplitude in the 4 kHz half-octave frequency band, where the risk for PTS in male sailors increased from approximately 3% to 20% as TEOAE amplitude decreased. When working in a noisy environment, OAEs may shift before there are measurable hearing threshold shifts. OAEs may be a diagnostic predictor for noise-induced-hearing-loss risk.

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Last updated 08 Nov 2009 04:37 PM