Relationship between the severity of cochlear deafness and eOAE recorded by ILO88

Abstract

After recording evoked otoacoustic emissions (eOAE) to click in 154 ears of 90 patients with cochlear deafness by using ILO88 which was made by Kemp and Bray for recording and analysing eOAE easily, the relationship between eOAE and severity of cochlear deafness was studied. The results obtained were as follows.
(1) The severity of hearing loss and eOAE detection.
If we judge the presence of eOAE with two criteria, the detection of eOAE wave and the reproducibility more than 40%, eOAE was detected with the reliability of 94% in 81 ears with the mean hearing loss at the 4 frequencies from 500Hz to 4000Hz less than 35dBHL. eOAE was not detected with the reliability of 89% and 92% in 73 and 63 ears with the mean hearing loss at the 4 frequencies more than 35dBHL and 44dBHL, respectively.
eOAE was not found with the reliability of 94% in 64 ears with the mean hearing loss at the 2 frequencies 1000Hz and 2000Hz more than 40dBHL.
(2) The severity of hearing loss and eOAE power.
In 84 ears with eOAE detection, negative correlation (r=-0.44) between the severity of hearing loss and eOAE power was found when total echo power and highest peak power at the frequencies from 1000Hz to 2000Hz in FFT pictures were used as an indicator of eOAE power.
From the results mentioned above, we concluded that ILO88 was useful for screening of cochlear deafness with the mean hearing loss more than 35 or 40dBHL at the frequencies from 500Hz to 4000Hz.