In Situ Otoacoustic Emission Monitoring to Assess the Effects of Noise Exposure on Hearing Health

Noise-induced hearing loss (NIHL) is the largest cause of action for indemnity in North American industries despite the widespread implementation of hearing conservation programs. Possible causes behind the onset of NIHL are the intervals between hearing tests which are generally too long and the tests are insufficiently sensitive to detect temporary hearing changes to act and prevent permanent hearing damage. Moreover, current noise regulations might be too lenient as to the permissible maximum noise levels. Short-interval hearing assessment could help to observe temporary changes in hearing health and prevent permanent damage. This study investigates the short-term effects of noise exposure characteristics using repeated measurements of otoacoustic emission (OAE) growth functions and presents the most significant predictors of hearing health changes as observed in sixteen individuals equipped with OAE earpieces. The experimental results of this study show that the impulsiveness and frequency spectrum of the noise level could be a possible cause of the decline in OAE levels. As a consequence, hearing conservation programs should consider taking these noise metrics into account for proper NIHL risk assessment. Such noise exposure and hearing health monitoring could greatly improve hearing conservation practices in the workplace by acting faster and eventually mitigate occupational hearing loss.