title: Optical cochlear implants: evaluation of surgical approach and laser parameters in cats.
abstract: Previous research has shown that neural stimulation with infrared radiation (IR) is spatially selective and illustrated the potential of IR in stimulating auditory neurons. The present work demonstrates the application of a miniaturized pulsed IR stimulator for chronic implantation in cats, quantifies its efficacy, and short-term safety in stimulating auditory neurons. IR stimulation of the neurons was achieved using an optical fiber inserted through a cochleostomy drilled in the basal turn of the cat cochlea and was characterized by measuring compound action potentials (CAPs). Neurons were stimulated with IR at various pulse durations, radiant exposures, and pulse repetition rates. Pulse durations as short as 50 mus were successful in evoking CAPs in normal as well as deafened cochleae. Continual stimulation was provided at 200 pulses per second, at 200 mW per pulse, and 100 mus pulse duration. Stable CAP amplitudes were observed for up to 10 h of continual IR stimulation. Combined with histological data, the results suggest that pulsed IR stimulation does not lead to detectable acute tissue damage and validate the stimulation parameters that can be used in future chronic implants based on pulsed IR.
authors.affiliation: Department of Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611-3008, USA.
authors.forename: Suhrud M
authors.initials: SM
authors.lastname: Rajguru
authors.forename: Agnella Izzo
authors.initials: AI
authors.lastname: Matic
authors.forename: Alan M
authors.initials: AM
authors.lastname: Robinson
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Fishman
authors.forename: Laura E
authors.initials: LE
authors.lastname: Moreno
authors.forename: Allison
authors.initials: A
authors.lastname: Bradley
authors.forename: Irena
authors.initials: I
authors.lastname: Vujanovic
authors.forename: Joe
authors.initials: J
authors.lastname: Breen
authors.forename: Jonathon D
authors.initials: JD
authors.lastname: Wells
authors.forename: Mark
authors.initials: M
authors.lastname: Bendett
authors.forename: Claus-Peter
authors.initials: CP
authors.lastname: Richter
mesh_terms: D000162:Acoustics; D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002415:Cats; D003051:Cochlea / Q000294:innervation / Q000473:pathology; D019929:Cochlear Implantation / Q000295:instrumentation / Q000379:methods*; D003638:Deafness / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D007259:Infrared Rays / Q000009:adverse effects; D007834:Lasers / Q000009:adverse effects; D008297:Male; D023421:Models, Animal; D055100:Optical Fibers; D013136:Spiral Ganglion / Q000502:physiology; D016896:Treatment Outcome