Cochlear Nerve Stimulation With Optical Radiation

Abstract

Problem Neural prosthetic devices are artificial extensions to the body that restore or supplement nervous system function that was lost during disease or injury. The devices stimulate remaining neural tissue with electric current, providing some input to the nervous system. Hereby, the challenge for neural prostheses is to stimulate remaining neurons selectively. However, electrical current spread does not easily allow stimulation of small neuron populations. In neural prostheses developments, particular success has been realized in the cochlear prostheses development. The devices bypass damaged hair cells in the auditory system by direct electrical stimulation of the auditory nerve. Stimulating discrete spiral ganglion cell populations in cochlear implant users’ ears is similar to the encoding of small acoustic frequency bands in a normal-hearing person's ear. In contemporary cochlear implants, however, the injected electric current is spread widely along the scala tympani and across turns. Consequently, stimulation of spatially discrete spiral ganglion cell populations is difficult. Methods Spiral ganglion cells in guinea pigs were stimulated with laser pulses from an Aculight Capella infrared laser. Results With our experiments we demonstrate that extreme spatially selective stimulation is possible using light. Conclusion Our long-term goal is to develop and build an optical cochlear implant prosthesis to stimulate small populations of spiral ganglion cells. Significance Our long-term goal is to develop and build an optical cochlear implant prosthesis to stimulate small populations of spiral ganglion cells. Support This project has been funded with federal funds from the National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Department of Health and Human Services, under Contract No. HHSN260-2006-00006-C / NIH No. N01-DC-6-0.