Restoration of auditory nerve synapses in cats by cochlear implants.
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.
Ryugo
D K
DK
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
Kretzmer
E A
EA
Niparko
J K
JK
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