Multi variant analysis of otoacoustic emissions and estimation of hearing thresholds: Transient evoked otoacoustic emissions

Evaluation of cochlear hearing loss by means of transiently evoked otoacous tic emissions is already established in clinical practice. However, accurat e prediction of pure-tone thresholds is still questioned and is still regar ded as troublesome. Both click- and tone-burst-evoked otoacoustic emissions at several intensity levels were measured and analysed in 157 ears from no rmally hearing and 432 ears from patients with different degrees of pure se nsory hearing loss using the ILO88/92 equipment. Results of otoacoustic emi ssions (OAE), elicited by clicks and tone-bursts at centre frequencies from 1 to 5 kHz, were analysed using two different statistical methods. Both mu ltivariate discriminant analysis and forward multiple regression analysis w ere used to determine which OAE variables were most discriminating and best at predicting hearing thresholds. We found that a limited set of variables obtained from both tone-burst and click measurements can accurately predic t and categorize hearing loss levels up to a limit of 60 dB HL. We found co rrect classification scores of pure-tone thresholds between 500 and 4000 Hz up to 100 per cent when using combined click and tone-burst otoacoustic me asurements. Prediction of pure-tone thresholds was correct with a maximum e stimation error of 10 dB for audiometric octave frequencies between 500 and 4000 Hz. Measurements of multiple tone-bursts OAEs have a significant clinical advan tage over the use of clicks alone for clinical applications, and a good cla ssification and prediction of pure-tone thresholds with otoacoustic emissio ns is possible.