Toward an optical cochlear implant

Cochlear implants (CIs) are considered one of the most successful neural prostheses. Today, more than 500,000 severely-to-profoundly deaf individuals have received a CI to restore some of their hearing. However, the performance of individual users varies largely. While some patients experience a notable improvement in functional hearing, others receive little benefit from CIs. Some situations, such as noisy listening environments, tonal languages, and music perception, remain challenging for all users. Reducing interaction between neighboring CI electrode contacts and more independent stimulation channels can improve CI performance. While reducing the interaction of adjacent channels during electrical stimulation is challenging, neural stimulation with light might be a novel approach to address the problem since it can evoke responses from small populations of neurons. Optical radiation can be delivered more selectively to groups of target neurons. It is anticipated that neural prostheses with enhanced neural fidelity can be developed by using optical stimulation. Two methods for optical stimulation are currently under investigation, optogenetics and infrared neural stimulation (INS). With the presentation, the efforts and advances leading to a novel cochlear implant incorporating electrical and optical stimulation are shown and discussed, including designing parameter considerations, device development, and testing prototypes.