title: Design and fabrication of multichannel cochlear implants for animal research.
abstract: The effectiveness of multichannel cochlear implants depends on the activation of perceptually distinct regions of the auditory nerve. Increased information transfer is possible as the number of channels and dynamic range are increased and electrical and neural interaction among channels is reduced. Human and animal studies have demonstrated that specific design features of the intracochlear electrode directly affect these performance factors. These features include the geometry, size, and orientation of the stimulating sites, proximity of the device to spiral ganglion neurons, shape and position of the insulating carrier, and the stimulation mode (monopolar, bipolar, etc.). Animal studies to directly measure the effects of changes in electrode design are currently constrained by the lack of available electrodes that model contemporary clinical devices. This report presents methods to design and fabricate species-specific customizable electrode arrays. We have successfully implanted these arrays in guinea pigs and cats for periods of up to 14 months and have conducted acute electrophysiological experiments in these animals. Modifications enabling long-term intracochlear drug infusion are also described. Studies using these scale model arrays will improve our understanding of how these devices function in human subjects and how we can best optimize future cochlear implants.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Epstein Laboratory, University of California San Francisco, San Francisco, CA 94143-0526, United States. srebscher@ohns.ucsf.edu
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Rebscher
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Hetherington
authors.forename: Russell L
authors.initials: RL
authors.lastname: Snyder
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Leake
authors.forename: Ben H
authors.initials: BH
authors.lastname: Bonham
mesh_terms: D032761:Animal Experimentation / Q000592:standards; D000818:Animals; D001306:Auditory Pathways / Q000502:physiology; D001309:Auditory Threshold / Q000187:drug effects / Q000502:physiology; D002415:Cats; D003051:Cochlea / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D019929:Cochlear Implantation / Q000295:instrumentation* / Q000379:methods*; D003054:Cochlear Implants / Q000592:standards*; D003056:Cochlear Nerve / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D017076:Computer-Aided Design / Q000295:instrumentation; D003638:Deafness / Q000628:therapy*; D004195:Disease Models, Animal; D004558:Electric Stimulation; D004567:Electrodes, Implanted / Q000592:standards; D004582:Electronics, Medical / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D016057:Evoked Potentials, Auditory, Brain Stem; D006168:Guinea Pigs; D006309:Hearing / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007245:Inferior Colliculi / Q000502:physiology; D015918:Infusion Pumps, Implantable / Q000592:standards; D008144:Loudness Perception / Q000187:drug effects / Q000502:physiology; D008839:Microelectrodes / Q000592:standards; D012533:Scala Tympani / Q000033:anatomy & histology / Q000601:surgery; D013045:Species Specificity