For more than 30 years, researchers in the Iowa Cochlear Implant Clinical Research Center (ICICRC) at the University of Iowa Roy J. and Lucille A. Carver College of Medicine have been focusing on patient outcomes and improving patient hearing with the development of a hybrid cochlear implant.
Now, thanks to a five-year, $12 million grant renewal from the National Institute on Deafness and Other Communication Disorders (NIDCD), part of the National Institutes of Health, UI Carver College of Medicine scientists can take their research even further.
“Some of the things we’re doing with this grant are applying basic neuroscience methodologies into our research,” says Bruce Gantz, MD, the Brian F. McCabe Distinguished Chair and UI professor and head of otolaryngology-head and neck surgery and director of the ICICRC.
What that means, he says, is that scientists are now not only looking at restoring hearing to a large number of patients, but determining how people separate speech from noise, which is a major problem of the hearing impaired.
With normal hearing, sound waves enter the ear canal and follow a path that eventually leads to the auditory nerve, which turns the waves into a signal the brain recognizes and understands as sound.
For people who have hearing loss and have received a standard cochlear implant, those sound waves follow the same path in the brain, but can be distorted and require the individual to delay recognition of the entire word or sentence. This delay creates confusion. As more sounds enter the path, the waves can become difficult for the brain to distinguish, Gantz says.
“A hybrid cochlear implant combines residual acoustic hearing with electrical speech processing of the cochlear implant. Recently our team has determined that the rate of recognition of words is improved because of the residual acoustic hearing. This enables the brain to react quicker to words and reduces listening effort. The low frequency hearing also allows individuals to separate speech from surrounding noise. We are just beginning to understand the timing and actual pathways in the brain that separate this information,” Gantz says. “We are using the implant to better understand the basic mechanisms that the brain uses to understand speech.”
The research will examine patients on an individual basis, helping researchers to understand why one person hears things differently than another.
“There is variability in outcomes,” says Camille Dunn, PhD, director of cochlear implants at the ICICRC and one of the researchers involved in the program. “Why are people with the same diagnoses having different outcomes? What is making that happen? That’s what we want to find out.”
“The better we are at understanding this process, the better we’re able to preserve that neural stimulation,” Gantz says. “This is a whole different way of looking at the work of the cochlear implant.”
This arm of the research will involve scientists from multiple disciplines across the University of Iowa, including computer science, neurosurgery, radiology, psychology, psychiatry, audiology, and music.
The four main areas of focus for this funding extension, and principal investigators for each, are: Dunn and Ruth Bentler, PhD, ecology; Paul Abbas, PhD, and Carolyn Brown, PhD, peripheral electrophysiology; Tim Griffiths, MD, and Bob McMurray, PhD, central auditory integration; and McMurray, cognitive dynamics of language processing . Gantz is director of the project, and Marlan Hansen, MD, is co-director.
The NIDCD grant has helped to fund the center’s research since it started in 1985, with funding now totalling $66 million.
--More information about the research and grant at: https://uihc.org/health-topics/research-studies-involving-cochlear-implants
Related media coverage:
http://www.kcrg.com/content/news/Marion-woman-talks-about-her-heriditary-hearing-loss-476729133.html