# Evaluating Human Cochlear Aging Using Otoacoustic Emissions (OAEs)

> **NIH NIH F32** · NORTHWESTERN UNIVERSITY · 2022 · $83,284

## Abstract

PROJECT SUMMARY/ABSTRACT
 Age-related hearing loss (ARHL) affects millions of individuals in the U.S. and is associated with
devastating health and economic outcomes. A primary site of age-related auditory dysfunction is the cochlea.
Cochlear aging begins as early as the fourth decade of life and stems from multiple etiologies. Therefore, early
and differential diagnosis will be key for the success of current and future treatments for age-related cochlear
dysfunction. However, current clinical tools are remarkably insensitive to early signs of aging in the auditory
periphery. Our long-term goal is to fill this clinical void using otoacoustic emissions (OAEs). This project takes
steps towards that goal by filling in critical gaps in knowledge that currently prevent OAEs from fulfilling their
diagnostic potential. We do this by systematically exploring the aging cochlea using OAEs, with a focus on the
underexplored cochlear base where age-related decline begins and where high frequencies are encoded.
 Our central hypothesis is that metabolic decline and increased irregularities (i.e., “roughness” due to
random tissue degradation) in the cochlear base are the earliest signs of cochlear aging, and that these signs
occur before they are detectable using current clinical measures (i.e., behavioral audiometry). We will test this
hypothesis by pursuing three specific aims that explore cochlear function in ears of varying ages deemed normal
by traditional measures. In Aim 1, we will characterize how age impacts the growth of two types of OAEs
(distortion and reflection) through the highest frequency of human hearing (20 kHz). This dual-emission approach
has proven promising in illuminating the mechanisms of age-related cochlear decline but has not yet been used
to characterize aging through the cochlear base. In Aim 2, we will assess the influence of aging on the generation
region of the same two types of OAEs. Understanding where OAEs arise along the cochlear partition and if they
are impacted by basal regions of the cochlea (which we hypothesize decline in an early stage of aging) is crucial
for both interpreting aging OAE patterns and for discerning the etiology of cochlear ARHL. In Aim 3, we will
examine the relationship between the generation region of OAEs, perceptual tuning, and age. A key question is
whether early signs of cochlear aging are detectable using perceptual measures not traditionally used in the
clinic (e.g., psychophysical tuning). We will systematically probe the relationship between cochlear tuning
estimates derived from distortion and reflection OAEs and psychophysical estimates of tuning and explore how
these relationships change with age. Understanding this will be crucial for determining if retrocochlear filtering is
significant in the aging ear, and for determining if OAEs may be used to assess cochlear tuning in aged ears.
 Collectively, this work will explore the use of otoacoustic emissions in detecting early age-related coc...

## Key facts

- **NIH application ID:** 10402811
- **Project number:** 5F32DC019557-02
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Courtney Coburn Glavin
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $83,284
- **Award type:** 5
- **Project period:** 2021-04-01 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10402811

## Citation

> US National Institutes of Health, RePORTER application 10402811, Evaluating Human Cochlear Aging Using Otoacoustic Emissions (OAEs) (5F32DC019557-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10402811. Licensed CC0.

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