Intraneural stimulation for auditory prosthesis: modiolar trunk and intracranial stimulation sites.
We have demonstrated recently in an animal model that stimulation with a penetrating auditory nerve electrode array is a feasible means of activating the ascending auditory pathway for auditory prosthesis. Compared to a conventional intrascalar cochlear implant, intraneural stimulation provides access to fibers serving a broader frequency range, activation of more tonotopically restricted fiber populations, lower thresholds, and reduced interference between simultaneously stimulated channels. The spread of excitation by a single intraneural electrode is broader than that by an acoustic tone but narrower than that by a cochlear-implant electrode. In the present study, we compare in an animal model two sites of intraneural stimulation: the modiolar trunk of the nerve accessed using a transcochlear approach and the intracranial portion of the nerve accessed using a posterior fossa approach. The two stimulation sites offer very similar thresholds, spread of activation, and dynamic ranges. The intracranial site differed in that there was greater between-animal variation in tonotopic patterns. We discuss the implications of these results for possible improvements in hearing prosthesis for human subjects.
Middlebrooks
John C
JC
Kresge Hearing Research Institute, Department of Otolaryngology and Biomedical Engineering, University of Michigan, 1301 East Ann Street, Ann Arbor, MI 48109-5506, USA. jmidd@umich.edu
Snyder
Russell L
RL
D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D001306:Auditory Pathways / Q000502:physiology*; D002415:Cats; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000502:physiology; D004558:Electric Stimulation; D008839:Microelectrodes; D023421:Models, Animal