Work

Efferent unmasking of speech-in-noise encoding?

Year: 2021

Type: article

Abstract: OBJECTIVE: The medial olivocochlear (MOC) reflex provides efferent feedback from the brainstem to cochlear outer hair cells. Physiologic studies have demonstrated that the MOC reflex is involved in "unmasking" of signals-in-noise at the level of the auditory nerve; however, its functional importance in human hearing remains unclear. DESIGN: This study examined relationships between pre-neural measurements of MOC reflex strength (click-evoked otoacoustic emission inhibition; CEOAE) and neural measurements of speech-in-noise encoding (speech frequency following response; sFFR) in four conditions (Quiet, Contralateral Noise, Ipsilateral Noise, and Ipsilateral + Contralateral Noise). Three measures of CEOAE inhibition (amplitude reduction, effective attenuation, and input-output slope inhibition) were used to quantify pre-neural MOC reflex strength. Correlations between pre-neural MOC reflex strength and sFFR "unmasking" (i.e. response recovery from masking effects with activation of the MOC reflex in time and frequency domains) were assessed. STUDY SAMPLE: 18 young adults with normal hearing. RESULTS: sFFR unmasking effects were insignificant, and there were no correlations between pre-neural MOC reflex strength and sFFR unmasking in the time or frequency domain. CONCLUSION: Our results do not support the hypothesis that the MOC reflex is involved in speech-in-noise neural encoding, at least for features that are represented in the sFFR at the SNR tested.

Source: International Journal of Audiology

DOI: 10.1080/14992027.2020.1862425

Authors: S. B. Smith, B. Cone

Institutions: The University of Texas at Austin, University of Arizona

Language: English

Topic: Hearing, Cochlea, Tinnitus, Genetics

Subfield: Sensory Systems

Field: Neuroscience

Domain: Life Sciences

Open Access status: green

Funder: National Institute on Deafness and Other Communication Disorders

Awards: Investigating the Relationship between Objective Measures of Binaural Hearing and Speech-in-Noise Performance in Middle-Aged Listeners, PHYSIOLOGY OF THE DEVELOPING OLFACTORY EPITHELIUM, G5977175176, How does the efferent auditory system function in the neural encoding and perception of speech-in-noise?