Multichannel optrodes for photonic stimulation

Abstract

Cochlear implants (CIs) are considered one of the most successful neural prostheses. Today about 350,000 individuals with severe-to-profound hearing loss have received a CI to restore some of their hearing. However, the performance of individual users varies largely. While some patients are able to communicate over the phone in different languages, others receive little benefit from CIs. For all CI users, noisy listening environments and music perception constitute a challenge.^{1 – 3} It has been argued that performance could be improved by reducing the interaction between neighboring CI electrode contacts, subsequently creating more independent channels for stimulation. More spatially selective stimulation with electric current can be achieved through multipolar stimulation, where multiple electrode contacts are used to narrow the current field.^{4 – 7} Another approach to increasing the number of different pitch percepts is called current steering.^{8 – 10} In this approach, neighboring electrodes are used simultaneously to “steer” the current to selected neuron populations between the two contacts. However, this technique does not introduce more independent channels for parallel stimulation.^{10 – 14}