By Andrea Boidman , Executive Director, Hearing Health Foundation
More people in the United States suffer from hearing loss than diabetes, osteoporosis, Alzheimer’s and autism combined. Hearing loss affects a wide spectrum of the population: young and old, and more men than women. Sixty percent of deployed military service men and women return from combat with noise-induced hearing loss and/or tinnitus, and one in five teenagers now suffer from hearing impairment. Hearing loss can seriously impact your quality of life. Depression and isolation are common side effects, and dementia is significantly more frequent in people with hearing loss. Most types of hearing loss are related to damage of the inner ear hair cells, which are essential for the conversion of sound to electrical signals and their transmission to the brain. The good news: There is now a real possibility of finding a way to regenerate those hair cells.
The words “cure” and “hearing loss” are not usually intertwined, so as Executive Director of Hearing Health Foundation, I am incredibly excited about the research being done by our Hearing Restoration Project (HRP), a consortium of the leading researchers who study the inner ear. Twenty-five years ago research partially funded by Hearing Health Foundation yielded the discovery that chickens can regenerate their inner ear hair cells. This means that their hearing is restored after being damaged. While we’ve learned that most non-mammalian vertebrates spontaneously regenerate their hair cells, mammals—including people—do not regenerate their inner ear hair cells. For that reason, hearing loss is permanent after hair cell damage.
Recently, Albert Edge, PhD, a member of the HRP consortium, and his team at Harvard School of Medicine/ Massachusetts Eye and Ear Infirmary, were able to spur the regeneration of inner ear hair cells in adult mice. This is the first time anyone has been successful in restoring hearing to a live, adult mammal. Edge's team stimulated new hair cell growth through the direct application in the inner ear of a class of drugs called gamma-secretase inhibitors, a treatment originally developed to combat Alzheimer’s disease. Researchers involved with HRP are hopeful that clinical trials for a biologic cure will begin in less than 10 years.
There is still much work to be done, but by having scientists working together through the HRP, we are getting closer to a cure for hearing loss for people.