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

Abstract

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.

Keywords:

• Otoacoustic emissions
• speech perception
• MOC
• contralateral suppression

Acknowledgments

The authors thank the participants for their time. The authors also thank Dr. Sa Shen for providing statistical consulting and for helpful comments on the Methods and Results sections. The authors also thank Dr. Justin Aronoff, Dr. Ron Chambers, and Dr. Mary Flaherty for helpful comments on this study.

Ethical approval and informed consent from participants

The research protocol was approved by the Institutional Review Board of the University of Illinois at Urbana-Champaign (IRB #20091). Written informed consent was obtained from each participant prior to enrolment.

Author contributions

I.B.M. designed the study, collected data, analysed data, and wrote the manuscript. A.L.S. collected data and assisted with data analysis and writing of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data are available upon request from the corresponding author, I.B.M.

Additional information

Funding

This work was funded by the Department of Speech and Hearing Science at the University of Illinois at Urbana-Champaign.