Rush University

Making Sense of Sound

Rush College of Health Sciences

In most auditory testing, the emphasis is on accuracy in speech recognition, since speech is our primary means of communication. But myriad sounds beyond language are key to our understanding of the world around us.

“A car honking, a baby crying, a fire alarm — recognizing these sounds can be important to our safety,” explained Valeriy Shafiro, Ph.D. “And there are also lots of nonlinguistic environmental sounds we enjoy listening to: the sound of the ocean, the wind in the trees when we walk in the woods.” Shafiro, an associate professor of communication disorders and principal investigator in the Rush Auditory Research Laboratory, conducts research in hearing and speech perception that focuses on finding new ways to diagnose auditory deficits and improve communication abilities in adults. These new diagnostic techniques have the potential to improve the quality of life of a variety of audiology patients — even well beyond the groups Shafiro is currently studying.

Addressing a rehab deficit 

Much of Shafiro’s lab’s past work, which has been funded by the National Institutes of Health (NIH), the American Speech-Language-Hearing Foundation (ASHFoundation) and the Hearing Health Foundation, formerly known as the Deafness Research Foundation, has assessed the ability of people with cochlear implants to recognize a variety of nonspeech sounds — a particularly useful means of auditory assessment in a large, urban medical center that treats many non-English speakers.

A recent study tested listeners’ ability to recognize those sounds with or without the contextual clues present in everyday life. For example, an ambiguous sound can be perceived as a burning fuse when preceded by the sound of a match being struck and followed by the sound of an explosion, but it may be perceived as bacon frying when surrounded by other kitchen sounds.

Credit: Rush University

Credit: Rush University

“Compared with people with normal hearing, people with cochlear implants show some pretty clear deficits in identifying environmental sounds as well as speech,” Shafiro said. “Research from several labs, including ours, shows the possibility for cochlear implant users to improve if they work on it. But there are few readily available opportunities for these patients to obtain rehabilitation, for reasons including travel difficulties, health care reimbursements and scope of practice.”

Shafiro is now evaluating the usefulness of Internet-based environmental sound and speech training for people who rely on cochlear implants in daily life. “A Randomized Controlled Trial to Evaluate the Benefits of an Internet-Based Auditory Training Program for Cochlear Implant Patients,” a two-year grant from the ASHFoundation, aims to help fill the rehabilitation deficit for adults who receive cochlear implants.

“With Internet access now widely available, patients can do the auditory exercises online, at their own pace and without having to travel,” Shafiro said. When completed, the study will give him and his colleagues a deeper understanding of the benefits and challenges of computerized auditory training.

Hearing-dementia link

Measuring listeners’ recognition of nonlinguistic sounds was also a component of a recent study from the Rush Auditory Research Laboratory in collaboration with the Rush Alzheimer’s Disease Center.

“Hearing, Speech and Episodic Memory in Older African-American and White Adults,” funded with a grant from the NIH, examined a topic of wide current interest: the relationship between aging, hearing loss and cognitive deficits. As Baby Boomers age, research like this has major implications for the health and well-being of older adults. “Some recent research has reported that people with a greater rate of age-related hearing loss also have a greater rate of cognitive decline,” Shafiro explained.

“Typical tests of working memory are based on retaining words or numbers, but we wanted to explore this further by measuring both nonspeech and speech perception.” 

Using tests previously designed by Stanley Sheft, senior researcher at the Rush Auditory Research Laboratory and principal investigator on the study, the team measured the ability of a cohort of community-dwelling older adults without known dementia to discriminate brief nonlinguistic sound patterns.

The addition of nonlinguistic sounds produced somewhat different results than those yielded by previous research. Although other studies have associated speech perception with cognitive performance, the Rush study did not find this correlation when measuring hearing thresholds or the ability to recognize speech in noise.

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However, “We found a relationship between working memory and the ability to discriminate brief auditory patterns,” said Shafiro, who hopes to revisit the study cohort in the future to see whether the tests may be predictive of the trajectory of cognitive decline.

This article was repurposed with permission from Rush University Medical Center, and originally appeared in the Rush College of Health Sciences magazine Impact. Valeriy Shafiro, Ph.D., is a 2008 Emerging Research Grants recipient.

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