Pilot Performance of a Chronic Intraneural Auditory Neuroprosthesis in Felines

Abstract

Auditory restoration for the hearing impaired is rapidly evolving through the use of implantable stimulation devices. Despite being the current state of the art, cochlear implants (CIs) have many limitations, including low stimulation electrode independence, a need for high stimulation currents, and the inability to reliably recruit low-frequency transducing fibers in the spiral ganglion. These drawbacks stem partly from the implant location, which is electrically separated from its spiral ganglion targets. Placement of an intraneural electrode array like the Utah Slanted Electrode Array (USEA) directly in cranial nerve VIII (CN VIII) could alleviate some of these constraints. However, all prior studies on USEAs for auditory restoration have been confined to acute evaluations, none lasting longer than 56 hours. In this abstract, we present the first use of the USEA as a chronic intraneural auditory neuroprosthesis, evaluate its performance over four months, and compare its performance to a comparable acute implant. We show stable electrophysiological signals tied to the activation of the auditory transduction pathway and impedance measures of the electrodes, both of which demonstrate a stable and functional chronic device. We also compare imaging taken between an acute functional implant and the chronic implant to compare similarities in the devices' locations and orientations in light of their functionality.