Sensitivity of Transient Evoked and Distortion Product Otoacoustic Emissions to the Direct Effects of Noise on the Human Cochlea

Abstract

Measurement of otoacoustic emissions (OAEs) has been proposed as a sensitive test t reliably assess the effects of noise exposure. The present study in humans was designed t evaluate the sensitivity and applicability of transient evoked OAEs (TEOAEs) and 2fl-f distortion product OAEs (DPOAEs) as quantitative indices of the functional integrity of th outer hair cells (OHC) during growth of and recovery from temporary threshold shift (TTS This was examined in two different groups of volunteers by measuring the per- and pos stimulatory effects of a one hour BBN and an on-site five hour exposure to loud music froi a discotheque. The results of both experiments show consistent growth and recover patterns for both DPOAEs and TEOAEs. For TEOAEs, both the reproducibility scores an signal to noise ratio values for the 4 kHz frequency band exhibited the greatest sensitivit The DPOAEs, on the other hand, showed the greatest sensitivity between 2 and 5.5 kH. Thus, both the TEOAEs and DPOAEs have a great potential in the detection of TTS after noise exposure.

Key Words:

• Temporary threshold shift
• Noise-induced hearing loss
• Otoacoustic emissions