University of Iowa News, June 7, 2006 --The Iowa Cochlear Implant Clinical Research Center (ICICRC) at the University of Iowa Roy J. and Lucille A. Carver College of Medicine has received its fourth consecutive grant renewal from the National Institute on Deafness and Other Communication Disorders, part of the National Institutes of Health (NIH). The cutting-edge research supported by this long-running grant has made the ICICRC one of the world's premier centers for cochlear implant clinical research.
The five-year, $10 million grant renewal will fund ongoing basic research, clinical trials and clinical outcomes research on cochlear implants in children and adults by researchers from the UI Carver College of Medicine and the UI College of Liberal Arts and Sciences Department of Speech Pathology and Audiology.
The center was established in 1985 when cochlear implants first became available and is directed by Bruce Gantz, M.D., the Brian F. McCabe Distinguished Chair and UI professor and head of otolaryngology - head and neck surgery, and Richard Tyler, Ph.D., UI professor of otolaryngology - head and neck surgery and speech pathology and audiology.
"The long-term NIH funding, now totaling $38 million over 25 years, allows ICICRC researchers to translate basic research on the auditory system into new cochlear implant technologies that improve speech understanding for adults who have become deaf as well as infants who are born deaf," Gantz said.
Gantz noted several important achievements that the center's multi-year studies have yielded: developing the "hybrid" cochlear implant that combines acoustic with electrical hearing; developing technology that allows measurement of auditory nerve response; pioneering the use of bilateral implants, which is becoming the standard of care; and improving music perception for implant users.
The hybrid implant, which uses electrical perception of high-frequency sounds while preserving a patient's residual acoustic hearing of low-frequency sounds, was developed at the UI and grew out of basic research funded by the grant. One-third of the 65 patients who have received these new cochlear implants nationwide have had the operation at UI Hospitals and Clinics.
"The hybrid implant can help a much larger population than the original cochlear implant because it can be used in individuals who have some residual hearing without destroying that ability, for instance those who have severe noise-induced hearing loss and those with severe high-frequency hearing loss due to aging. Both types of hearing loss are widespread in farmers and our aging population in Iowa," Gantz said. "By preserving residual acoustic hearing and combining it with electrical speech processing provided by the implant we can bring the patient's word understanding up. Preserving residual low-frequency hearing also allows the patient to retain music appreciation and to hear better in noisy settings," he added.
Gantz said the hybrid implant also will be useful for children who may have lost their high-frequency hearing because of chemotherapy for tumors, or children born with high-frequency hearing loss. Without being able to hear high-frequency sounds, these children cannot learn to speak clearly.
The hybrid electrode may even allow patients to take advantage of potential future advances in regenerative medicine.
"Preservation of the inner ear is going to be important in the future because we think we will eventually be able to regenerate the inner ear," Gantz said. "By putting a short electrode in an infant we may be able to safeguard the progenitor cells until such a time that the research enables us to use those cells to regenerate inner ear function."
A goal of the ICICRC is to refine the criteria for identifying patients who would benefit from the hybrid implant. Another fundamental advance produced by UI studies is known as the neural response telemetry system. This system, which allows measurement of the residual nerves in the ear, was developed at the UI and now is standard in all three FDA-approved cochlear implants.
"It lets us stimulate the hearing nerve and then measure the residual activity of the nerve through the implant," Gantz explained. "This helps us to 'set' the implant in young children. It also helps us measure the long-term effects of electrical stimulation on the auditory system to see if the residual neural function changes over time."
Gaining a better understanding of how the auditory system responds to electrical stimulation over time is an important component of the research grant. The UI team will follow 372 previously implanted adults and children and recruit over 100 new adults and children to look at the long-term impact of electrical stimulation on the auditory system.
UI researchers also have pioneered the use of bilateral cochlear implants -- implants in both ears. Studies have shown that children given one standard cochlear implant can develop normal speech and hearing. Implanting a second device in the other ear helps with localization and hearing in noisy environments. Ongoing research will examine the advantages of bilateral implants in adults and children and of combining a standard implant in one ear with a hybrid implant in the other.
Another research project that promises future benefits is an effort by UI scientists to improve music perception and appreciation for implant users.
Researchers also will study speech in noisy settings and will investigate whether lowering the age at which infants receive an implant, from one year to seven months, improves speech and language development.
In addition to Gantz and Tyler, principal investigators on the ICICRC grant include Paul Abbas, Ph.D., professor and chair of the Department of Speech Pathology and Audiology and professor of otolaryngology - head and neck surgery; Carolyn Brown, Ph.D., professor of speech pathology and audiology and otolaryngology - head and neck surgery; Kate Gfeller,
Ph.D., professor of music and speech pathology and audiology; Bruce Tomblin, Ph.D., professor of speech pathology and audiology; Christopher Turner, Ph.D., professor of speech pathology and audiology, and otolaryngology - head and neck surgery; and Marlan Hansen, M.D., assistant professor of otolaryngology - head and neck surgery.
University of Iowa Health Care describes the partnership between the UI Roy J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics and the patient care, medical education and research programs and services they provide. Visit UI Health Care online at www.uihealthcare.com.
Story Source: University of Iowa Health Science Relations, 5135 Westlawn, Iowa City, Iowa 52242-1178
itsnt166.iowa.uiowa.edu/uns-archives/2006/june/060706cochlear-grant.html
