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Titolo:
Olivocochlear efferent vs. middle-ear contributions to the alteration of otoacoustic emissions by contralateral noise
Autore:
Buki, B; Wit, HP; Avan, P;
Indirizzi:
Univ Auvergne, Fac Med, Lab Biophys Sensorielle EA 2667, F-63001 Clermont Ferrand, France Univ Auvergne Clermont Ferrand France F-63001 1 Clermont Ferrand, France Semmelweis Univ, ENT Dept, Budapest, Hungary Semmelweis Univ Budapest Hungary weis Univ, ENT Dept, Budapest, Hungary AZG Groningen, ENT & Audiol Dept, Groningen, Netherlands AZG Groningen Groningen Netherlands Audiol Dept, Groningen, Netherlands
Titolo Testata:
BRAIN RESEARCH
fascicolo: 1, volume: 852, anno: 2000,
pagine: 140 - 150
SICI:
0006-8993(20000103)852:1<140:OEVMCT>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
COMPOUND ACTION-POTENTIALS; COCHLEAR MICROMECHANICAL PROPERTIES; ACOUSTIC STIMULATION; DISTORTION PRODUCTS; SOUND STIMULATION; GUINEA-PIG; REFLEX; SUPPRESSION; HUMANS; BUNDLE;
Keywords:
medial olivocochlear bundle; otoacoustic emission; middle-ear impedance; stapedius reflex; middle-ear pressure;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
53
Recensione:
Indirizzi per estratti:
Indirizzo: Avan, P Univ Auvergne, Sch Med, Biophys Lab, POB 38, F-63001 Clermont Ferrand, France Univ Auvergne POB 38 Clermont Ferrand France F-63001 rand, France
Citazione:
B. Buki et al., "Olivocochlear efferent vs. middle-ear contributions to the alteration of otoacoustic emissions by contralateral noise", BRAIN RES, 852(1), 2000, pp. 140-150

Abstract

The medial olivocochlear efferent bundle is the key element of a bilateralefferent reflex activated by sound in either ear and acting directly on cochlear outer hair cells (OHC) via numerous cholinegic synapses. It probablycontributes to regulating the mechanical activity of the cochlea Otoacoustic emissions, being sounds emitted by the cochlea as a reflection of its activity and suppressed by efferent activation, are increasingly considered to be the privileged tool for a noninvasive assessment of the efferent reflex. However, confounding effects on otoacoustic emissions can occur. A primary influence is middle-ear muscle reflex activation, which shares common features with the effects of cochlear efferent activation. We report a systematic comparison of the responses of human otoacoustic emissions to efferentactivation by low-level noise in the contralateral ear to various middle-ear manipulations (reflex contractions of the stapedius muscle induced by high-level contralateral noise, moderate middle-ear pressure changes). The profiles of level and phase changes of otoacoustic emissions as a function offrequency were highly specific to the origin of the effects. The changes induced by middle-ear manipulations matched the predictions computed from a standard lumped-element middle-ear model, with one or two peaks around the resonance frequency(ies) of the involved subsystem, stapes or tympanic membrane. In contrast, the efferent effect was completely different, exhibitinga broadband-level suppression associated with a small phase lead. We propose that a careful vector analysis of otoacoustic emission modifications enables the identification of the contribution of the efferent reflex without ambiguity even when it is mixed with middle-ear effects. Thereby, otoacoustic emissions can be used more reliably as noninvasive probes of efferent olivocochlear function. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

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Documento generato il 30/11/20 alle ore 06:50:48