Lack of correlation between medial olivocochlear reflex strength and sentence recognition in noise

Objective: The medial olivocochlear (MOC) reflex provides unmasking of sounds in noise, but its contribution to speech-in-noise perception remains unclear due to conflicting results. This study determined associations between MOC reflex strength and sentence recognition in noise in individuals with normal hearing. Design: MOC reflex strength was assessed using contralateral inhibition of transient-evoked otoacoustic emissions (TEOAEs). Scores on the AzBio sentence task were quantified at three signal-to-noise ratios (SNRs). Additionally, slope and threshold of the psychometric function were computed. Associations between MOC reflex strength and speech-in-noise outcomes were assessed using Spearman rank correlations. Study sample: Nineteen young adults with normal hearing participated, with data from 17 individuals (mean age = 21.8 years) included in the analysis. Results: Contralateral noise significantly decreased the amplitude of TEOAEs. A range of contralateral inhibition values was exhibited across participants. Scores increased significantly with increasing SNR. Contrary to hypotheses, there were no significant correlations between MOC reflex strength and score, nor were there any significant correlations between MOC reflex strength and measures of the psychometric function. Conclusions: Results found no significant monotonic relationship between MOC reflex strength and sentence recognition in noise. Future work is needed to determine the functional role of the MOC reflex.