By John Galvin, PhD and Javia Headley, Marketing Communications Manager
Cochlear implant research at The House Institute started in 1957 when a patient alerted William House, MD, to the work of Andre Djourno. Djourno was a neurophysicist who implanted an electrode into the ear of a patient living with severe ear disease and found the potential to bring sound to the inner ear through electrical stimulation. In 1960, Dr. William House tried to replicate the work of Djourno with several patients undergoing surgery with great success. Soon after, Dr. House implanted his first cochlear implant system for long-term use. Surgical procedures and implant technology have continued to evolve ever since.
Researchers at the House Institute currently have several ongoing projects designed to optimize the cochlear implant for various patient groups. For our cochlear implant research scientist, John Galvin, PhD, one area of promising research is combining acoustic hearing and electric hearing with the cochlear implant in patients that have substantial acoustic hearing in the ear to be implanted or in the contralateral ear. Dr. Galvin also collaborates with researchers worldwide on various cochlear implant projects, including computer-based auditory training at home, emotion communication, and music perception.
When asked about the future directions of the cochlear implant, Dr. Galvin pointed out some near-future technologies that may benefit patients with hearing loss.
Optical cochlear implant – For present cochlear implants, individuals are able to perceive sound due to electric current from electrodes implanted in the cochlea. This method does not provide very good sound resolution. Researchers are studying the feasibility of using light to activate the surviving neurons in the cochlea. Infrared light has been shown to offer greater sound resolution, but much work remains to optimize the technology.
Adaptive signal processing – Researchers are developing signal processing to optimize the sound and reduce noise before the sound reaches the cochlear implant. Artificial Intelligence and cloud computing allows for better analysis of the auditory scene and improves speech understanding for various listening environments.
Utilizing the cochlear implant as a drug delivery system – When electrodes are implanted into the inner ear, insertion trauma may occur, leading to an inflammatory response. Researchers continue to develop “drug-eluting” electrodes that can deliver drugs to reduce implantation and fibrotic growth and better preserve cochlea health after implantation.
Penetrating electrodes – In present cochlear implant devices, electrodes are positioned within the cochlea, often at a distance from the surviving neurons that require substantial electric current. As current spreads over this distance, this greatly limits the sound resolution, which is problematic for challenging listening tasks such as speech in noisy environments, music perception, etc. Researchers are developing electrodes to penetrate the auditory nerve. If successful, penetrating electrodes could dramatically reduce the current spread and increase sound quality.