# Examination of the bidirectional relationship between hearing loss and Alzheimer Disease pathology

> **NIH NIH R21** · UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN · 2021 · $201,937

## Abstract

ABSTRACT
Recent epidemiological studies have revealed an association between aging-related hearing loss
(ARHL) and Alzheimer Disease (AD). Both of these disorders deprive individuals of their quality
of life and both are rapidly rising in prevalence, given the aging of our population. Therefore, it is
critical that we understand how AD and ARHL are related and whether this relationship can be
used as leverage to better understand and treat both disorders. One key question is whether
ARHL and AD are linked because of common risk factors or whether there is a causal relationship
between the two (i.e., does ARHL exacerbate AD pathology?). This question cannot be answered
effectively in human subjects because of the inability to independently manipulate hearing loss.
Therefore, in the current study, we employ two animal models of AD (a model of sporadic and a
model of familial AD) and ask whether manipulation of the peripheral auditory system alters AD
pathology. To do this, we employ a novel model of sporadic AD that is based on cell-cycle
dysregulation – a phenomenon that is commonly observed in brain specimens from AD patients.
These AD model mice therefore do not carry a specific mutation in a gene that directly processes
amyloid beta or tau. Nevertheless, they have been shown to display characteristic plaques and
tangles, similar to what is seen in the AD brain, and neurodegeneration, which is not seen in most
other mouse models of sporadic AD. The model of familial AD that will be used is the APP/PS1
mouse because it has been shown to display central auditory dysfunction and has a time course
of pathology that matches with our sporadic AD model. In Aim 1, we will test both peripheral and
central auditory function in these mice and hypothesize that, like AD patients, they will have more
impairment in central, compared to peripheral, auditory function. In Aim 2, we will induce hearing
loss and examine for exacerbation of AD pathology and induction of a progressive
neurodegenerative phenotype using a combination of serial FDG PET imaging and behavioral
analyses. We hypothesize that hearing loss will worsen AD pathology and exploratory analyses
will be done to determine if changes are more severe in central auditory compared to non-auditory
regions. Successful completion of this work will, for the first time, determine the nature of the
association between hearing loss and AD pathology. If a causal association is found, future work
will determine the molecular mechanisms of this association and whether mitigation of ARHL also
diminishes AD pathology. Given the advancing pace of successful interventions for ARHL (aural
rehabilitation, “smart” hearing aids, cochlear implants, etc.), this research could lay the
groundwork for early intervention for ARHL to diminish the burden of dementia.

## Key facts

- **NIH application ID:** 10196576
- **Project number:** 1R21DC019473-01
- **Recipient organization:** UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
- **Principal Investigator:** DANIEL A LLANO
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $201,937
- **Award type:** 1
- **Project period:** 2021-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10196576

## Citation

> US National Institutes of Health, RePORTER application 10196576, Examination of the bidirectional relationship between hearing loss and Alzheimer Disease pathology (1R21DC019473-01). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10196576. Licensed CC0.

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