This week, Science Friday covered a novel approach to cochlear implant optimization.In a healthy ear, sound enters the ear canal and vibrates the eardrum, which affects three small bones, called the middle ear ossicles. The ossicles are connected to the inner ear, which contains the cochlea. The cochlea is filled with conductive fluids and tiny hairs called auditory fibers. When the vibration of sound makes its way through the ear, these nerves are stimulated and send a signal to the brain. In many deaf patients, the auditory nerves are damaged. The signal never gets to the brain, resulting an absence of perception of sound.
Rene Gifford, an audiologist at Vanderbilt, heads a research team that is working to restore that sound with cochlear implants. The implants are inserted into the inner ear, and electrodes act as a substitute for the missing auditory nerves. But the team ran into an interesting problem: it worked too well. Because external stimulation fired all of the electrodes, the brain was overwhelmed in its perception of sound. When you hear things, all auditory fibers aren’t firing— only a select few. In order to “de-muddle” the sound perception, Giffords team deactivating certain electrodes to improve audio clarity. Sisler-Dinwiddie, a pediatric audiologist at Vanderbilt, was one of the first patients to undergo the deactivation, and her word recognition improved by 50%. Now, Gifford and her team are working to improve the auditory perception of children, who “are showing even greater promise than adult [patients]”. Watch the full video feature below.