ABSTRACT The proposed project will build and evaluate the safety and design needs of a new type of intracranial auditory prosthesis that targets the auditory nerve between the cochlea and the brainstem (auditory nerve implant, ANI) in order to substantially improve hearing performance over the current standard of care, the cochlear implant (CI). Current CIs provide crucial speech information to many recipients, but do not restore normal hearing, and are particularly challenged in noisy or complex acoustic environments. Despite concerted efforts over the past 25 years, little overall improvement in CI performance has been obtained, primarily due to the poor electrode- neural interface in which the CI electrodes are immersed in cochlear fluids and separated from the auditory nerve by the cochlea's bony wall. The new approach will build upon encouraging data from animal studies, well-established human surgical techniques to access the auditory nerve, and high-density electrode and safe stimulation technologies currently available for human use in order to test the safety and efficacy of the ANI that enables direct contact between the electrodes and the auditory nerve. The ANI provides great promise of improved speech and music perception for its prospective recipients, by overcoming the challenge that has limited improvements in CIs for the past quarter century. The first aim is to design and build a full ANI system in accordance with regulatory requirements, including necessary reliability, safety, functional, biocompatibility, and sterilization testing for human use. The ANI system will be built by combining a well-established CI device in the auditory implant field with a novel electrode and cabling technology already being evaluated in human patients for other clinical applications. The second aim is to refine the ANI surgery in human cadaver experiments and acutely during other relevant in vivo operations to consistently position and anchor the electrode array and cabling into the target region. The third aim is to develop and validate critical psychophysical tests to properly evaluate the performance of the ANI during the pilot human study, which can then inform the design of a future clinical ANI device. The fourth aim is to seek regulatory approvals and set up the clinical trial infrastructure and monitoring entities. The fifth and final aim is to perform a pilot ANI study in up to three deaf patients to obtain safety, reliability and functionality data that can properly guide the design of a proceeding clinical device and a feasibility study.

NARRATIVE Cochlear implants provide crucial speech information to many recipients, but are still far from normal hearing. Performance of cochlear implants have not improved much over the past 25 years due to a poor electrode- neural interface in which electrodes are immersed in the fluid of the cochlea and separated from the target auditory nerve by the cochlea's bony wall. The proposed project will build and evaluate a new intracranial auditory prosthesis implanted directly into the auditory nerve that could provide a greater number of effective channels of information to the brain and potentially transform the auditory implant field.