DISTORTION PRODUCT VERSUS TRANSIENT EVOKED OTOACOUSTIC EMISSION IN NOISE INDUCED HEARING LOSS

Abstract

Noise is a leading cause of sensorineural hearing loss in our present day society . High-level noise, occurring either continuously or as single or internittent impulses, leads fu:st to reversible, temporary threshold shift and eventually results m sensorineural hearing loss beginning around 4 to 6 kHz .

Otoacoustic emiSSions used to detect the changes m hearing due to noise exposure.

In tllis study we evaluate both DPOAEs and TEOAEs in noise induced hearing loss and also to compare between them .

The study included two groups, the frrst, control group consisted of 20 normal ears and the second, and the study group consisted of 100 ears that were exposed to noise for more than 5 years. Pure-tone audiometry, tympanometry, TEOAE and DPOAE were done to both groups .

The result has shown significant decrease in the amplitude in the study group compared with the control group . Also the DPOAEs were frequency specific than TEOAEs .