# Consequences of cochlear synaptopathy on signal detection in noisy environments: perception and central auditory processing

> **NIH NIH R21** · OREGON HEALTH & SCIENCE UNIVERSITY · 2020 · $168,784

## Abstract

Project summary
Noise-induced auditory nerve loss (synaptopathy) has recently been identified as a form of hearing loss that may
be widespread among humans. In this synaptopathy, moderate noise exposure results in the degeneration of
auditory nerve synapses without hair cell loss or elevated auditory thresholds. This type of hearing loss cannot
be detected by hearing tests conventionally used in the clinic, thus it has been termed “hidden hearing loss”.
This loss of auditory input may lead to degraded processing of sounds in the auditory cortex, particularly in the
presence of background noise. In particular, synaptopathy may explain why 10% of the general population
experiences difficulty understanding speech in noisy environments despite normal audiometric thresholds. To
develop diagnostic and treatment strategies that address difficulty understanding speech in noise, there is a
critical need to characterize the specific perceptual and central processing deficits resulting from synaptopathy.
Since the Mongolian gerbil has a hearing range similar to that of humans, it is a well-established species for
studying the physiological and perceptual consequences of hearing loss. This study uses the Mongolian gerbil
to generate an animal model of synaptopathy more relevant to the range of human hearing than previous animal
studies. Aim 1 identifies the appropriate noise exposure parameters for inducing synaptopathy in gerbil. Aim 2
tests whether synaptopathy results in poorer detection of amplitude modulations in the presence of background
noise. Aim 3 tests whether synaptopathy results in degraded cortical representation of amplitude modulations
and speech when background noise is present.
Understanding the consequences of cochlear synaptopathy on central auditory processing and auditory
perception is significant because this knowledge will help establish whether cochlear synaptopathy is a clinically-
relevant problem. Furthermore, the animal model and techniques developed in this study can be used to study
other deficits that may be associated with synaptopathy (e.g., hyperacusis and tinnitus) and evaluate the efficacy
of strategies for diagnosing and treating synaptopathy. This study represents a significant step towards the long
term goal of understanding how hearing loss affects central auditory processing and auditory perception.

## Key facts

- **NIH application ID:** 9858321
- **Project number:** 5R21DC016969-03
- **Recipient organization:** OREGON HEALTH & SCIENCE UNIVERSITY
- **Principal Investigator:** Brad N Buran
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $168,784
- **Award type:** 5
- **Project period:** 2018-03-01 → 2022-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9858321

## Citation

> US National Institutes of Health, RePORTER application 9858321, Consequences of cochlear synaptopathy on signal detection in noisy environments: perception and central auditory processing (5R21DC016969-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9858321. Licensed CC0.

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