The medial olivocochlear reflex in children during active listening

Abstract

Objective: To determine if active listening modulates the strength of the medial olivocochlear (MOC) reflex in children. Design: Click-evoked otoacoustic emissions (CEOAEs) were recorded from the right ear in quiet and in four test conditions: one with contralateral broadband noise (BBN) only, and three with active listening tasks wherein attention was directed to speech embedded in contralateral BBN. Study sample: Fifteen typically-developing children (ranging in age from 8 to14 years) with normal hearing. Results: CEOAE levels were reduced in every condition with contralateral acoustic stimulus (CAS) when compared to preceding quiet conditions. There was an additional systematic decrease in CEOAE level with increased listening task difficulty, although this effect was very small. These CEOAE level differences were most apparent in the 8–18 ms region after click onset. Conclusions: Active listening may change the strength of the MOC reflex in children, although the effects reported here are very subtle. Further studies are needed to verify that task difficulty modulates the activity of the MOC reflex in children.

Key Words::

• Click-evoked otoacoustic emissions (CEOAE)
• contralateral inhibition
• medial olivocochlear (MOC) reflex
• auditory Stroop task
• attention

Acknowledgements

The authors would like to thank Dr. David Velenovsky for his theoretical contributions to this work and Holden Sanders for his assistance with data collection. We also thank Dr. Jacek Smurzynski and two anonymous reviewers for their critique of earlier versions of this paper, and for Figure 1, provided by one of the anonymous reviewers.

Notes

Declaration of interest: The authors have no conflicts of interests to declare.

This preliminary work was supported by NIH T32 Training Grant #DC009398-04 and NIH-NIDCD K-24 Grant #DC-8826, Barbara Cone, PI. Portions of these data were presented at the 2013 American Auditory Society meeting in Scottsdale, Arizona and at the AudiologyNow! 2013, in Anaheim, USA. Ongoing support is provided by a Student Research Grant to Spencer Smith from the American Academy of Audiology Foundation.

Notes

1. Also known as suppression (Velenovsky & Glattke, 2002).

2. Behavioral data on the remaining subjects were corrupted by a software-related storage error.