Varsha Rallapalli –

Northwestern University
Communication Sciences & Disorders
Evanston, IL 60208
United States

Jeff Crukley – University of Toronto; McMaster University
Emily Lundberg – University of Colorado, Boulder
James M. Kates – University of Colorado, Boulder
Kathryn Arehart – University of Colorado, Boulder
Pamela Souza – Northwestern University

Popular version of 3aPP1 – Modeling the relationship between listener factors and signal modification: A pooled analysis spanning a decade
Presented at the 186th ASA Meeting
Read the abstract at

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Imagine yourself in a busy restaurant, trying to focus on a conversation. Often, even with hearing aids, the background noise can make it challenging to understand every word. While some listeners manage to follow the conversations rather easily, others find it hard to follow along, despite having their hearing aids adjusted.

Studies show that cognitive abilities (and not just how well we hear) can affect how well we understand speech in noisy places. Individuals with weaker cognitive abilities struggle more in these situations. Unfortunately, current clinical approaches to hearing aid treatment have not yet been catered to these individuals. The standard approach to setting up hearing aids is to make speech sounds louder or more audible. However, a downside is that hearing aid settings that make speech more audible or attempt to remove background noise, can unintentionally modify other important cues, such as fluctuations in the intensity of the sound, that are necessary for understanding speech. Consequently, some listeners who depend on these cues may be at a disadvantage. Our investigations have focused on understanding why listeners with hearing aids experience these noisy environments differently and developing an evidence-based method for adjusting hearing aids to each person’s individual abilities.

To address this, we pooled data from 73 individuals across four different published studies from our group over the last decade. In these studies, listeners with hearing loss were asked to repeat sentences that were mixed with background chatter (like at a restaurant or a social gathering). The signals were processed through hearing aids that were adjusted in various ways, changing how they handle loudness and background noise. We measured how these adjustments applied to the noisy speech affected the ability of the listeners to understand the sentences. Each of these studies also used a measurement to capture how the hearing aids and background noise together alter the speech sounds (signal fidelity) heard by the listener.

Hearing aidsFigure 1. Effect of individual cognitive abilities (working memory) on word recognition as signal fidelity changes.

Our findings reveal that listeners generally understand speech better when the background noise is less intrusive, and the hearing aids do not alter the speech cues too much. But there’s more to it: how well a person’s brain collects and manipulates speech information (their working memory), their age, and the severity of their hearing loss all play a role in how well they understand speech in noisy situations. Specifically, those with lower working memory tend to have more difficulty understanding speech when it is obscured by noise or altered by the hearing aid (Figure 1). So, improving the listening environment by reducing the background noise and/or choosing milder settings on the hearing aids could benefit these individuals.

In summary, our study indicates that a tailored approach that considers each person’s cognitive abilities could lead to better communication, especially in noisier situations. Clinically, the measurement of signal fidelity may be a useful tool to help make these decisions. This could mean the difference between straining to hear and enjoying a good conversation over dinner with family.

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