Peripheral factors in loudness adaptation with OAE effects

Abstract

Tone decay (TD), the ipsilateral comparison paradigm (ICP), and the monaural simple adaptation (SA) procedure assess loudness adaptation differently; this may all be peripheral but it has not been previously compared in one study. Transient evoked oto-acoustic emissions (TEOAE) have their source in the outer hair cells of the cochlear periphery. A significant correlation (r=−0.60) between contralateral suppression of transient evoked OAEs and tone decay adaptation (r=−0.60) has been reported [Collet et al., Audiology 31, 1–7 (1992)]. A significant correlation (r=−0.36) between ICP adaptation and contralateral suppression of TEOAEs has been found [Ernest M. Weiler, Hongwei Dou et al., J. Acoust. Soc. Am. 103, 3052 (1998)]. Comparison of TD, ICP, and SA with suppression of TEOAEs used repeated measures testing of 75 students (20–35 yrs) of mixed nationalities. Significant correlations were found, but not at all values, between TD, ICP, SA, and suppression of TEOAEs at 80, 60, and 70 dB. A principle components factor analysis found factor I based on suppression, and factor II based on monaural adaptation. It was concluded that the ICP, TD, and SA are primarily peripheral in origin. TD and ICP each include variation in stimulus intensity which may play a role in triggering perception of loudness adaptation.