Short-term buildup of contralateral olivocochlear emission suppression and its effect on the words-in-noise test

This study aimed to quantify the short-term buildup of olivocochlear suppression of transient-evoked otoacoustic emissions (TEOAEs) in humans by varying the duration of a contralateral suppressor. Specifically, we tested whether suppression magnitude changes with different durations of interrupted wideband noise (2, 4, and 6 seconds) and examined whether efferent suppression strength relates to speech-in-noise performance.

A within-subject design was used to compare TEOAE suppression across three contralateral block durations. Behavioural speech-in-noise measures (WIN test) were obtained to evaluate potential associations between efferent activity and perceptual outcomes.

Thirty-one adults (ages 20-29) with clinically normal hearing and no history of otologic or neurologic disorders participated.

Olivocochlear suppression magnitude increased with longer (6s) contralateral noise durations, indicating a short-term buildup of efferent activity over several seconds. No significant ear differences were observed. While suppression strength did not correlate with the 50% speech recognition threshold, stronger suppression was associated with steeper psychometric slopes, suggesting a link between efferent function and perceptual efficiency.

Findings demonstrate a time-dependent buildup of medial olivocochlear activity. The relationship between suppression magnitude and psychometric slope implies that stronger efferent function may contribute to adaptive listening strategies in challenging acoustic environments.