# Investigating the relationship between directional microphones, compression, and working memory in realistic spatial conditions

> **NIH NIH K01** · NORTHWESTERN UNIVERSITY · 2022 · $100,913

## Abstract

Project summary
Hearing aids have specialized features to improve access to sounds for the hearing-impaired listener. The
choice of appropriate hearing aid settings is integral to the hearing rehabilitative process. Researchers and
clinicians have been influenced by previous work showing that individual cognitive abilities, including working
memory are associated with hearing aid benefit, especially in adverse listening conditions. However, previous
research is limited to omnidirectional microphone settings and unrealistic listening conditions. Such conditions
fail to recognize that most hearing aids are fit with directional processing that may improve the listening
environment, and that typical environments contain speech and noise signals in a range of spatial locations.
Therefore, the broad goal of this research is to understand how patient variables interact with hearing aid
signal processing in realistic listening conditions in order to effectively treat hearing-impaired individuals in
communications situations that are most important to them. The proposed work is in alignment with NIDCD's
mission to conduct and support behavioral research and research training in interventions (i.e. hearing aids)
that substitute for lost/impaired sensory and communication function (i.e., hearing loss).
The specific aims examine the relationship between working memory and hearing aid signal processing
(WDRC in the presence of microphone directionality) in spatial conditions ideal for directionality (Aim 1) and
realistic spatial conditions (Aim 2). In a clinical trial, hearing-impaired listeners will use wearable hearing aids
with different hearing aid processing settings (WDRC speeds, microphone directionality patterns and
technology) and identify speech in different listening conditions (spatially varying speech and noise).
Performance across conditions will be related to listeners' auditory abilities and working memory capacities
using a mixed design. Existing acoustic metrics will be used to associate individual outcomes to overall signal
fidelity across conditions.
The K01 award will enable the PI to build upon her existing research and clinical experience with hearing aids
and provide structured training in the following areas: a) focused research on the impact of microphone
directionality on individual hearing aid outcomes in realistic spatial conditions, b) designing a clinical trial with
wearable hearing aids, and c) advancing scientific communication skills. Research and training experience
through this award will help the PI achieve her long-term goal of performing rigorous independent research in
the individualized care of hearing-impaired adults. The proposed work will take place at Northwestern
University under the mentorship of Dr. Pamela Souza and Dr. Richard Freyman.

## Key facts

- **NIH application ID:** 10307562
- **Project number:** 5K01DC018324-03
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Varsha Hariram Rallapalli
- **Activity code:** K01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $100,913
- **Award type:** 5
- **Project period:** 2019-12-01 → 2023-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10307562

## Citation

> US National Institutes of Health, RePORTER application 10307562, Investigating the relationship between directional microphones, compression, and working memory in realistic spatial conditions (5K01DC018324-03). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10307562. Licensed CC0.

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