# Influences of the Efferent System on Human Auditory Function

> **NIH NIH K23** · UTAH STATE HIGHER EDUCATION SYSTEM--UNIVERSITY OF UTAH · 2020 · $51,444

## Abstract

PROJECT SUMMARY/ABSTRACT
Although current hearing devices improve listening in quiet environments, they do little to improve speech
understanding in noisy backgrounds. The long-term goal of this research program is to fully understand the
relationship between auditory perception and physiological mechanisms responsible for adapting to the local
soundscape. The objective of this particular application is to understand the role of the medial olivocochlear
(MOC) reflex in the perception of fluctuating sounds and on speech-in-noise performance in normal hearing
and hearing impaired listeners using perceptual, electrophysiological, and auditory modeling techniques. The
central hypothesis of the proposed research is that cochlear hearing loss limits the ability of the MOC reflex to
regulate cochlear gain, thus preventing the putative perceptual and neural benefits associated with the reflex.
The rationale of the proposed research is that a detailed description of the influence of the MOC reflex on
human auditory function has the potential to translate to a better understanding of why hearing devices provide
little benefit to improving speech-in-noise performance in hearing impaired adults. This detailed description will
be obtained by completing the following specific aims: 1) Determine the role of the MOC reflex in the detection
of temporal fluctuations and the identification of speech syllables in noise; 2) Determine the effect of eliciting
the ipsilateral MOC reflex on the compound action potential (CAP) in human subjects with and without cochlear
hearing loss; and 3) Simulate the influence of the MOC reflex on auditory function in listeners with and without
cochlear hearing loss. This approach is innovative because it links empirical findings from normal and impaired
perception and electrophysiology to a quantitative theoretical framework using a computational auditory model.
The proposed research is significant because it is expected to lead to 1) a clear understanding of the role of
the MOC reflex in humans with normal and impaired auditory systems, 2) effective procedures for evaluating
the influence of the MOC reflex on auditory function, 3) novel MOC-inspired signal processing algorithms for
hearing devices, and 4) a better quality of life for hearing impaired individuals by providing improved
communication with family, friends, and co-workers. To achieve the research objectives of this application, the
principal investigator (PI) has designed a career development plan to acquire expertise in speech perception
and electrophysiological methods, and deepen expertise in computational auditory modeling. Training in these
areas will be obtained by frequent communication and planned mentoring activities with senior scientists in the
PI's mentoring/advising team. This training will provide the PI with the skills needed to become an independent
investigator, and prepare for a career of research productivity.

## Key facts

- **NIH application ID:** 10168114
- **Project number:** 3K23DC014752-05S1
- **Recipient organization:** UTAH STATE HIGHER EDUCATION SYSTEM--UNIVERSITY OF UTAH
- **Principal Investigator:** Skyler G. Jennings
- **Activity code:** K23 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $51,444
- **Award type:** 3
- **Project period:** 2016-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10168114

## Citation

> US National Institutes of Health, RePORTER application 10168114, Influences of the Efferent System on Human Auditory Function (3K23DC014752-05S1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10168114. Licensed CC0.

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