The Role of the Medial Olivocochlear Reflex in Psychophysical Masking and Intensity Resolution in Humans: A Review

Abstract

This review addresses the putative role of the medial olivocochlear (MOC) reflex on psychophysical masking and intensity resolution in humans. A framework for interpreting psychophysical results in terms of the expected influenced of the MOC reflex is introduced. This framework is used to review the effects of a precursor or contralateral acoustic stimulation on 1) simultaneous masking of brief tones, 2) behavioral estimates of cochlear gain and frequency resolution in forward masking, 3) the build-up and decay of forward masking, and 4) measures of intensity resolution. Support, or lack thereof, for a role of the MOC reflex in psychophysical perception is discussed in terms of studies on estimates of MOC strength from otoacoustic emissions and the effects of resection of the olivocochlear bundle in patients with vestibular neurectomy. Novel, innovative approaches are needed to resolve the dissatisfying conclusion that current results are unable to definitively confirm or refute the role of the MOC reflex in masking and intensity resolution.