Evoked Otoacoustic Emissions and Sensorineural Hearing Loss

Following Kemp's original studies, several others have confirmed the existence of otoacoustic emissions. Their clinical relevance remains, however, to be clarified. The various published studies have concerned small series. This study sought to specify otoacoustic emission characteristics in relation to sensorineural hearing loss (148 ears of 76 subjects). The results show that the presence of otoacoustic emissions drops as a function of hearing loss and that there is a highly statistically significant correlation between otoacoustic emission threshold and hearing loss at the 1000-Hz frequency. Otoacoustic emissions are never found when hearing loss at 1000 Hz exceeds 40 dB hearing level and when the mean audiometric hearing loss (at 500, 1000, 2000, and 4000 Hz) exceeds 45 dB hearing level. The main practical conclusion is that otoacoustic emission presence indicates middle frequency functional integrity of the outer hair cells of Corti's organ. Absence of otoacoustic emissions is harder to interpret.