# Neural Pathophysiology and Suprathreshold Processing in Older Adults with Elevated Thresholds

> **NIH NIH P50** · MASSACHUSETTS EYE AND EAR INFIRMARY · 2020 · $543,640

## Abstract

Project Summary
Hearing impairment is a common chronic health condition of older age that has been linked to adverse
changes in social and emotional well-being. Steeply sloping, high-frequency hearing loss (HFHL) is the most
common sensorineural hearing loss profile for middle-aged and older adults with a past history of noise
exposure. A common complaint of subjects with HFHL relates to a difficulty understanding speech in fluctuant
background noise. Individual thresholds for recognizing speech in noise vary widely, are not well predicted
from the audiogram, and are not reliably improved by amplification. The underlying motivation for this project is
to identify physiological and perceptual biomarkers that more accurately predict speech in noise recognition in
subject with HFHL, as compared to age-matched subjects with normal hearing (NH). Our underlying
hypothesis is that impaired speech in noise processing for subjects with HFHL can be predicted from abnormal
neural coding of low-frequency signals, where thresholds are normal. In Aim 1, we employ a series of
physiological and psychophysical tests to identify the stage of neural processing (from auditory nerve to cortex)
and mode of neural processing (from the auditory nerve compound action potential to subcortical encoding of
stimulus fine structure) that most directly map onto speech in noise outcomes in HFHL and NH subjects. To
further probe the linkage between neural processing of low-frequency signals and speech in noise recognition,
we will employ a new approach to enhance speech in noise processing through an immersive, closed-loop
audiomotor software training interface. Our preliminary data suggest that speech in noise recognition can be
significantly improved in subjects with sensorineural hearing loss that were randomly assigned to closed-loop
audiomotor training, as compared to subjects assigned to a placebo auditory training interface. However, it is
not known which physiological and perceptual predictors of speech processing are also modified to support a
change in speech recognition thresholds. Aim 2 will address this point through a randomized, double-blind
placebo-controlled study design that will compare the neural and physiological predictors of speech processing
before training, after training and at a follow-up test after training has been discontinued. By identifying the
biomarkers of neural processing that not only predict speech outcomes in a baseline condition, but also track
dynamic shifts in speech processing over the course of an intervention, these studies may identify the most
robust neural predictors of speech in noise processing as well as possible targets for future therapies.

## Key facts

- **NIH application ID:** 9987325
- **Project number:** 5P50DC015857-04
- **Recipient organization:** MASSACHUSETTS EYE AND EAR INFIRMARY
- **Principal Investigator:** Daniel B. Polley
- **Activity code:** P50 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $543,640
- **Award type:** 5
- **Project period:** — → —

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9987325

## Citation

> US National Institutes of Health, RePORTER application 9987325, Neural Pathophysiology and Suprathreshold Processing in Older Adults with Elevated Thresholds (5P50DC015857-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9987325. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*