Establishing critical differences in ear-canal stimulus amplitude for detecting middle ear muscle reflex activation during olivocochlear efferent measurements

Abstract

Objective: Assessments of the medial olivocochlear reflex (MOCR) may have clinical utility. The MOCR is measured using contralateral inhibition of otoacoustic emissions but concurrent activation of the middle ear muscle reflex (MEMR) confounds test interpretation. MEMR activation can be detected using the change in ear-canal stimulus amplitude without versus with an MOCR elicitor. This study provides a description of how critical differences in ear-canal stimulus amplitude can be established.

Design: Clicks were presented in right ears without and with a contralateral MOCR elicitor. Ear-canal stimulus amplitudes were measured. Two measurements without an elicitor were used to develop critical differences. MEMR activation was considered present if the difference in ear-canal stimulus amplitude without versus with an elicitor exceeded the critical difference.

Study sample: Forty-six normal-hearing adults (mean age = 23.4 years, 35 females) participated, with data from 44 participants included in the final analysis.

Results: Two participants exceeded the 95% critical difference. The 80, 90 and 99% critical differences are also reported for reference.

Conclusions: Results suggest that the contralateral elicitor can evoke the MEMR in a small number of participants. The methods described in this paper can be used for developing equipment- and clinic-specific critical differences for detecting MEMR activation.

Keywords:

• Acoustic reflex
• contralateral inhibition
• MOC
• olivocochlear efferent
• otoacoustic emissions

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Acknowledgments

The author thanks the participants for their time and effort. The author also thanks Kristin M. Johnson and Zoë A. Dinger for assistance with data collection. The author also thanks the three anonymous reviewers for their comments on the manuscript. A subset of the participants in this study contributed data to previously-published studies from our group (Mertes 2018; Mertes, Johnson, and Dinger 2019). The current study included data from additional participants and represents a new application of the data.

Disclosure statement

No potential conflicts of interest were reported by the author.

Additional information

Funding

This work was supported by the American Speech-Language-Hearing Foundation under a 2017 New Investigators Research Grant and by the Office of the Vice Chancellor for Research, University of Illinois at Urbana-Champaign under an Arnold O. Beckman Award.