Effect of Contralateral Medial Olivocochlear Feedback on Perceptual Estimates of Cochlear Gain and CompressionReportar como inadecuado




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Journal of the Association for Research in Otolaryngology

, Volume 17, Issue 6, pp 559–575

First Online: 22 August 2016Received: 13 February 2015Accepted: 17 June 2016

Abstract

The active cochlear mechanism amplifies responses to low-intensity sounds, compresses the range of input sound intensities to a smaller output range, and increases cochlear frequency selectivity. The gain of the active mechanism can be modulated by the medial olivocochlear MOC efferent system, creating the possibility of top-down control at the earliest level of auditory processing. In humans, MOC function has mostly been measured by the suppression of otoacoustic emissions OAEs, typically as a result of MOC activation by a contralateral elicitor sound. The exact relationship between OAE suppression and cochlear gain reduction, however, remains unclear. Here, we measured the effect of a contralateral MOC elicitor on perceptual estimates of cochlear gain and compression, obtained using the established temporal masking curve TMC method. The measurements were taken at a signal frequency of 2 kHz and compared with measurements of click-evoked OAE suppression. The elicitor was a broadband noise, set to a sound pressure level of 54 dB to avoid triggering the middle ear muscle reflex. Despite its low level, the elicitor had a significant effect on the TMCs, consistent with a reduction in cochlear gain. The amount of gain reduction was estimated as 4.4 dB on average, corresponding to around 18 % of the without-elicitor gain. As a result, the compression exponent increased from 0.18 to 0.27.

Keywordsmedial olivocochlear reflex MOCR temporal masking curve TMC click-evoked otoacoustic emissions CEOAEs contralateral acoustic stimulation cochlear amplification Mark D. Fletcher and Katrin Krumbholz contributed equally to this work.

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Autor: Mark D. Fletcher - Katrin Krumbholz - Jessica de Boer

Fuente: https://link.springer.com/







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