# Brain Plasticity and Clinical Consequences of Adult-Onset Asymmetric Hearing Loss

> **NIH NIH R56** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2021 · $685,236

## Abstract

PROJECT SUMMARY
Permanent sensorineural asymmetric hearing loss (AHL) disrupts extraction of interaural information for binaural
processing. Using a cutoff of at least 15 dB interaural difference as definition of AHL, prevalence estimates vary
widely, from 1% to 50%. Among cohorts with occupational noise exposure, AHL prevalence ranges from 15%-
49%. Critical clinical consequences include difficulty with sound target identification in noisy environments and
degradation of spatial hearing. Beyond those impairments, the aidable poorer ear in AHL is at risk for
accelerated decline and often burdened by tinnitus. There is a wide gap in our understanding of the relationship
between central nervous system changes along the continuum of AHL magnitudes, audiological and
psychoacoustical outcomes, and tinnitus perception. Closing this knowledge gap would be the first step to
advance diagnostic tools and inspire innovative treatments for AHL. Informed by anchoring neuroimaging and
audiological data from normal hearing and single-sided deafness, the most extreme form of AHL, we propose to
close this knowledge gap.
A comprehensive study on the clinical consequences of AHL should address hearing performance under adverse
conditions, spatial hearing, and tinnitus outcomes, and their central neural correlates. We propose a longitudinal
within-subject neuroimaging features and clinical assessments study of AHL before and after treatment by
amplification. We will use resting-state magnetoencephalographic imaging (RS-MEGI) and functional magnetic
resonance imaging (RS-fMRI), task-based MEGI, and diffusion MRI to examine temporal, functional and
structural features, and audiological and psychoacoustical tests to evaluate hearing performance and tinnitus
outcomes. This observational study will collect data from participants who will be treated by routine amplification
with individualized tinnitus sound therapies, as required, for AHL. We will evaluate test-retest reliability of
neuroimaging features, and assess neuroimaging features, hearing performance, and tinnitus outcomes at
baseline and at months 3, 6 and 12 following treatment. The specific aims of this research are to examine: 1)
AHL clinical outcomes, 2) AHL auditory interhemispheric temporal organization using MEGI, and 3) AHL whole
brain functional and structural neuroimaging features using resting-state MEGI and fMRI (functional), task-based
MEGI (functional), and diffusion MRI (structural).

## Key facts

- **NIH application ID:** 10412442
- **Project number:** 1R56DC019282-01A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** STEVEN WAN CHEUNG
- **Activity code:** R56 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $685,236
- **Award type:** 1
- **Project period:** 2021-09-01 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10412442

## Citation

> US National Institutes of Health, RePORTER application 10412442, Brain Plasticity and Clinical Consequences of Adult-Onset Asymmetric Hearing Loss (1R56DC019282-01A1). Retrieved via AI Analytics 2026-05-29 from https://api.ai-analytics.org/grant/nih/10412442. Licensed CC0.

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