Medial Olivocochlear Reflex Strength Predicts Musical Perception and Speech-in-Noise Performance in Nonmusicians

The medial olivocochlear (MOC) reflex enhances the signal-to-noise ratio (SNR) in the cochlea and is implicated in auditory scene analysis. Although musicians often exhibit robust MOC function, it remains unclear whether related auditory advantages stem from innate predisposition or training-induced plasticity. This study investigated the relationship between individual variations in MOC reflex function, musical perception, and speech-in-noise (SIN) performance in nonmusicians.

Fifty-eight normal-hearing nonmusicians were divided into two groups on the basis of the magnitude of their MOC reflex strength, quantified via contralateral suppression of transient evoked otoacoustic emissions (cTEOAEs) measured separately in each ear. Participants with suppression values above the sample median were assigned to the high MOC function group, whereas those with values below the median comprised the low MOC function group. All participants underwent pure-tone and high-frequency audiometry, auditory efferent system evaluation, speech-in-noise (SIN) testing at 0 and -10 dB SNRs, and musical perception assessment using the Montreal Battery for Evaluation of Amusia (MBEA).

The group with stronger MOC reflex activity demonstrated significantly better performance on MBEA scale and memory subtests and superior SIN perception at 0 dB SNR. Hierarchical regression confirmed MOC strength as a significant predictor of SIN performance at -10 dB SNR. Mediation analysis revealed that musical perception abilities partially mediated the relationship between MOC function and SIN performance.

Variations in MOC reflex function among nonmusicians constitute a foundational biological trait that shapes auditory perception, supporting both musical abilities and speech-in-noise processing in the absence of formal musical training.