Distortion product otoacoustic emission fine structure of symphony orchestra musicians

Otoacoustic emissions (OAE) are sounds produced by the healthy inner ear. They can be measured as low-level signals in the ear canal and are used to monitor the functioning of outer hair cells.Several studies indicate that OAE might be a more sensitive measure to detect early noise-induced hearing losses than puretone audiometry. The distortion product otoacoustic emission (DPOAE) fine structure is obtained when the ear is stimulated by dual tone stimuli using a high frequency resolution. It is characterized by quasi-periodic variations across frequency, as it can be observed in the hearing threshold microstructure also. In this study DPOAE fine structures and hearing thresholds are obtained for symphony orchestra musicians both for left and right ears and before and after the orchestra rehearsal. DPOAE fine structures are analyzed with an automatic classification algorithm, which describes the ripple pattern by parameters. A difference between left and right ears could be detected for the DPOAE level but not for the fine structure parameters. No difference between the measures taken before and after exposure could be observed.