Hearing aids have existed, in one form or another, for hundreds of years. Wearable, electrical hearing aids have been around for about 75 years. More recently—over the past 50 years—cochlear implants have been used to create or restore hearing for some of the estimated 30 million people in modern societies affected by permanent hearing loss and deafness (including many age 65 and older).
The older technologies produce similar outcomes: Amplifying and filtering sound to enhance hearing. Are there better ways to improve hearing?
Researchers at Rochester Institute of Technology aim to surpass the inherent limitations of hearing aids and cochlear implants through the development of a micropump for administering drugs and gene-based therapy treatments. The goal: improved treatment and curing of auditory dysfunction.
The project is supported by a $922,048 award from the National Institutes of Health—National Institute on Deafness and Other Communication Disorders.
"Pioneering studies in the areas of auditory gene therapy and chemotherapy have produced exciting results showing potential for protection and regeneration of sensory systems in the inner ear," explains David Borkholder, the project's principal investigator and an assistant professor of electrical engineering in RIT's Kate Gleason College of Engineering. More elaborate treatments are needed to achieve full restoration of hearing in animal models and for translational results in human clinical trials."
Borkholder is collaborating with the University of Rochester Medical Center to develop an implantable, refillable, variable-flow micropump platform for intracochlear drug delivery for deafness therapy research. Initially, a device will be designed for and tested using mice.
"This micropump will enable chronic, calibrated delivery of multiple therapeutic agents that is not possible with existing pump technologies" explains Borkholder, an expert in biomedical engineering and micoelectromechanical systems.
The project is expected to provide a detailed understanding of acceptable dose and timing profiles for intracochlear drug delivery in mice without detriment to cochlear function. The technology is scaleable to use in humans and may be particularly useful in pediatrics.
Robert D. Frisina, a professor and associate chair of otolaryngology and professor of biomedical engineering and neurobiology and anatomy at the University of Rochester Medical Center, is serving as research mentor. Frisina is also distinguished researcher in biological sciences in RIT's College of Science and professor of communication sciences and associate director of the International Center for Hearing and Speech Research at the National Technical Institute for the Deaf at RIT.
"Although some people are helped with hearing aids, the majority of those with hearing loss or hearing-related balance disorders go untreated," Frisina says. "Future biomedical interventions will be aimed at treating the underlying biological problems that cause permanent sensorineural hearing loss rather than trying to amplify and filter incoming sounds with hearing aids.
"A critical step for implementing research aimed at repairing or restoring nerve cells that are damaged or missing in the inner ear is to develop more precise, calibrated micropumps for delivering chemotherapeutic, gene-therapy or stem-cell therapeutic agents, first for animal research, then for clinical trials. This project is a critical step forward in developing microfabricated pumps. Longer-term goals include developing and testing inner ear micropumps for clinical applications to treat human inner-ear hearing and balance problems."
Also participating in the project are XiaoXia Zhu, a University of Rochester postdoctoral research fellow; Dean Johnson, an RIT microsystems engineering doctoral student; and Sean O'Brien and Avery Sonnenburg, RIT engineering master's students. Lynn Fuller, RIT professor of microelectronic engineering, and Thomas Gennett, RIT professor of chemistry, are consultants on the project.