Apports de l'analyse temporelle des otoémissions acoustiques provoquées transitoires à l'identification de leurs sources

Transient-evoked otoacoustic emissions (t-EOE) are of growing importance in clinical routine as an objective tool for screening hearing losses due to cochlear dysfunction. For this purpose, their presence or absence is thought to be a reliable criterion. Apart from such applications, the question of their generation and propagation in a normal or impaired cochlea remains challenging. In particular, it seems that several of their properties are sensitive to the status of the whole cochlea, thus if it was confirmed, it would not be straightforward to predict the alterations of t-EOE components as a function of audiometric data, and the reverse would be even more delicate. The goal of this work was to substantiate the hypothesis that t-EOE properties depend the whole cochlear status by analysing their temporal patterns in human ears, with either irreversible audiometric alterations attributed to noise-induced hearing loss, or reversible changes in basal cochlear function produced by high-frequency masking tones. The temporal patterns examined by wavelet analysis were conspicuously dependent on the cochlear status at high frequencies. In the first experiment (NIHL), EOE patterns enabled to predict whether or not the audiogram was normal around 8 kHz. With high-frequency masking, very complex changes in temporal patterns were observed. These results suggest that EOE and hearing loss are correlated in a complex manner