Right Ear Advantage Drives the Link between Olivocochlear Efferent “Antimasking” and Speech in Noise Listening BenefitsAbstracts of the Annual MidWinter Research Meeting of the Association for Research in Otolaryngology (2015)
The human cochlea receives feedback from the medial olivocochlear (MOC) efferents arising in the caudal brainstem whose “antimasking” role enhances peripheral signal detection in adverse listening environments. In many aspects of audition, listeners show a right ear advantage, achieving superior behavioral performance with right- compared to left-ear stimulation. Here, we examined if a similar right-ear advantage extended to both speech-in-noise (SIN) listening and to contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs), a proxy measure of MOC strength. We found that speech reception thresholds in noise, measured using the QuickSIN test, were lower in the right- (RE) compared to left ear (LE). TEOAE suppression with contralateral broadband noise was also greater in REs. A strong negative correlation was observed between performance on the QuickSIN and the amount of cochlear suppression in REs, indicating that lower speech reception thresholds in noise were associated with larger amounts of MOC-related cochlear feedback. This brain-behavioral correlation was not observed in LEs. The rightward bias in SIN abilities, contralateral suppression of TEOAEs, and stronger association between physiological and perceptual measures for RE stimulation is consistent with the brain’s left hemisphere dominance for speech-language processing. We infer that corticofugal feedback from left cerebral cortex via the MOC efferent system may sensitize the right cochlea for signal-in-noise detection thereby facilitating figure-ground contrast and improving degraded speech listening abilities.
Citation InformationGavin M. Bidelman and Shaum P. Bhagat. "Right Ear Advantage Drives the Link between Olivocochlear Efferent “Antimasking” and Speech in Noise Listening Benefits" Abstracts of the Annual MidWinter Research Meeting of the Association for Research in Otolaryngology Vol. 38 (2015) p. 172 - 172
Available at: http://works.bepress.com/shaum-bhagat/82/