# Role of olivocochlear efferents in age-related hearing dysfunction

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2022 · $393,966

## Abstract

Project Summary:
Age-related hearing deficits are a prevalent public health problem, and major knowledge gaps remain in our
understanding of the underlying central neural mechanisms. The long-term goal of our research is to
understand how aging and hearing loss affects organization of central auditory pathways concurrent with
peripheral degeneration, and how these changes contribute to hearing difficulties. The central hypothesis of
the proposed research is that neuromodulatory feedback pathways become dysregulated with age, particularly
the olivocochlear (OC) efferents, reducing the aging brain's capacity to protect against peripheral damage and
compensate for diminished peripheral input. In younger adults, OC neurons protect against damaging sounds,
enhance processing of acoustic transients in noise, and enhance auditory selective attention. These processes
are disrupted in aging listeners, and dysfunction of the OC system is likely a contributing factor. The primary
objectives of the proposed research are to investigate age-related changes in the organization and function of
the OC pathways, define their effects on the quality of the afferent sensory signals sent back to the brain, and
reveal how these changes contribute to age-related auditory deficits. A secondary goal is to understand how
genetic and environmental manipulation of OC neurons can be leveraged to protect against age-related
auditory deficits. We will pursue these goals with three Specific Aims 1) Quantify age-related changes in OC
neuronal morphology and their relationship to cochlear afferent degeneration and hearing in noise; 2) Quantify
age-related changes in the OC efferent-modulated sensory signal received and processed by the auditory
brainstem; 3) Determine the protective effects of genetic and environmental manipulations to increase OC
system activation against age-related hearing deficits. Our approach will integrate multiple techniques to
understand the relationship between the olivocochlear system and age-related hearing decline, including the
auditory brainstem response, single unit physiology, behavior, and quantitative anatomical analysis of
peripheral and central components of OC neurons in aging mouse models. These studies will lead to a better
understanding of age-related changes in brain-controlled modulation of sensory function. In the future, these
pathways may be manipulated to protect against age-related hearing decline and improve hearing in the
presence of competing sounds.

## Key facts

- **NIH application ID:** 10434879
- **Project number:** 5R01DC017620-05
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Amanda M. Lauer
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $393,966
- **Award type:** 5
- **Project period:** 2018-07-09 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10434879

## Citation

> US National Institutes of Health, RePORTER application 10434879, Role of olivocochlear efferents in age-related hearing dysfunction (5R01DC017620-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10434879. Licensed CC0.

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