# The contributions of age related changes in the sound localization pathway to central hearing loss

> **NIH NIH R01** · UNIVERSITY OF COLORADO DENVER · 2021 · $578,135

## Abstract

Project Summary
One of the most common medical conditions in any aging society is presbycusis, or age-related hearing loss.
Approximately one third of American adults suffer from this condition typically starting at middle age, and
about half of adults over 70 years have a substantial hearing impairment. One of the mechanisms of
presbycusis happens in the central nervous system and is termed central hearing loss. Older adults with central
hearing loss may have normal or near normal audiograms yet have problems carrying on a conversation in
complex environments, i.e. situations where multiple sound sources are active at the same time, such as a busy
restaurant, a public place, or any situation where background noises are active. The main reason for this
difficulty is that affected individuals have trouble perceptually isolating sound sources of interest (e.g., the
voice of the speaker they want to listen to) effectively from other sources, presumably because the neural
mechanisms that perform this computation are less effective. We propose a combined human subjects and
animal model study to tackle this issue. Specifically, we propose to study the contribution of age-related
changes in the sound localization pathway, located in the auditory brain stem, to this phenomenon. The
overarching hypothesis of this proposal is that precise timing of neural activity within the sound localization
pathway declines with age, leading to less precise binaural hearing and sound localization abilities. We
hypothesize that these changes contribute to decreased behavioral performance in complex acoustic
environments in both humans and animal models. For the human component, we will test the sound
localization and hearing in noise abilities of “young” and “old” listeners, and relate decreased behavioral
performance in older listeners to decreased temporal precision of neural activity in the sound localization
pathway (aim 1). We will show that aged Mongolian gerbils recapitulate these age-related changes, making
them good models to study this human condition (aim 2). We will then explore cellular mechanisms behind the
decreased temporal precision of neural activity (aim 3). The expected results from this study will help
determine the role of the sound localization pathway in this common medical condition, will help diagnose
central hearing loss more objectively, will directly suggest mechanisms for the development of future medical
interventions, and will help resolve a key challenge to healthy aging.

## Key facts

- **NIH application ID:** 10164754
- **Project number:** 5R01DC017924-03
- **Recipient organization:** UNIVERSITY OF COLORADO DENVER
- **Principal Investigator:** Achim Klug
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $578,135
- **Award type:** 5
- **Project period:** 2019-06-07 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10164754

## Citation

> US National Institutes of Health, RePORTER application 10164754, The contributions of age related changes in the sound localization pathway to central hearing loss (5R01DC017924-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10164754. Licensed CC0.

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