title: Restoration of auditory nerve synapses in cats by cochlear implants.
abstract: Congenital deafness results in abnormal synaptic structure in endings of the auditory nerve. If these abnormalities persist after restoration of auditory nerve activity by a cochlear implant, the processing of time-varying signals such as speech would likely be impaired. We stimulated congenitally deaf cats for 3 months with a six-channel cochlear implant. The device used human speech-processing programs, and cats responded to environmental sounds. Auditory nerve fibers exhibited a recovery of normal synaptic structure in these cats. This rescue of synapses is attributed to a return of spike activity in the auditory nerve and may help explain cochlear implant benefits in childhood deafness.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University Center for Hearing and Balance, 720 Rutland Avenue, Baltimore, MD 21205, USA. dryugo@bme.jhu.edu
authors.forename: D K
authors.initials: DK
authors.lastname: Ryugo
authors.forename: E A
authors.initials: EA
authors.lastname: Kretzmer
authors.forename: J K
authors.initials: JK
authors.lastname: Niparko
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D002415:Cats; D003051:Cochlea / Q000648:ultrastructure; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000378:metabolism*; D017626:Cochlear Nucleus / Q000648:ultrastructure; D003638:Deafness / Q000151:congenital / Q000378:metabolism / Q000628:therapy; D005072:Evoked Potentials, Auditory; D006309:Hearing; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure