August 15, 2017
Middle-aged adults often show up in hearing clinics complaining that they have trouble hearing, but standard tests show their hearing ability, known to scientists as pure-tone threshold, is only slightly impaired, says Professor and Department Chair of Communication Disorders Karen Helfer. Typically, they leave with no confirmation of their sense that they are hearing less well.
To explore this disconnect and to investigate the idea that what middle-aged adults may be noticing is not hearing loss but an early age-related change in listening effort, she has a new five-year, $2,020,470 grant from the NIH’s National Institute on Deafness and Other Communication Disorders.
Helfer and colleagues will study not only listening effort – the need to expend extra effort to comprehend speech in certain situations – but also will evaluate the effectiveness of new over-the-counter hearing aids increasingly being marketed to middle-aged adults as “personal sound amplifiers.”
The new studies build on Helfer’s many previous investigations of young adults, middle-aged people between ages 45 and 64, and older adults, all of which have explored peoples’ ability to understand speech in the presence of background sounds, whether made up of meaningful words or just noise.
She explains, “We found a really interesting pattern in several studies. When the background sounds are noise, carrying no information, middle-aged adults performed more like younger listeners. But when the background sound was speech, the middle-aged participants had trouble understanding, and performed much like the older participants. Finding this in several studies led us to this project that will look into how middle-aged adults understand speech in complex environments.”
To determine whether middle-aged adults need to apply more listening effort in certain situations, Helfer and her co-investigator, Professor of Kinesiology Richard Van Emmerik, will ask study participants do two tasks at once.
She says, “We’re particularly excited to measure listening effort while making our study participants walk while listening. We believe that if listening is easy, factors of your walking mechanics such as stride length, posture and coordination won’t change. But if the listening task takes more effort, your walking mechanics, speed and other parameters will change in a measurable way. We feel these situations have real-life implications because many people regularly walk and talk to friends.”
Further, Helfer explains, earlier studies have shown that as listening effort increases, memory for the details of the conversation deteriorates. In these experiments, the researchers will use memory for speech as a measure of listening effort because listeners must not only understand but remember the content of their conversations.
For the evaluation of personal sound amplifiers, Helfer and fellow Professor of Communication Disorders Richard Freyman, with Pamela Souza ‘90, a Communication Disorders alumna and nationally recognized hearing researcher and expert on hearing aids now at Northwestern University, will examine how these affect middle-aged adults’ performance in a variety of challenging listening situations.
Helfer says, “There has been very little research on these devices, so we want to explore how well they work. They are not as sophisticated, and do not amplify as much as traditional hearing aids, but they may be adequate to help with mild hearing loss. And if they can improve the notoriously low acceptance rate for hearing aids and serve as a gateway that brings people to seek hearing health care sooner, they would be valuable.”
Crucial questions to be explored in this part of the study include whether over-the-counter hearing aids should be used in both ears or if one is sufficient, whether it takes time to benefit from their use, and whether they can ease listening effort, she adds.
The researchers will be recruiting subjects for these studies beginning in Fall 2017. Those interested may contact Helfer’s lab at: 413/345-6760 or by email at: email@example.com.