[Effect of intracochlear electrical stimulation on action potential of auditory nerve in guinea pigs]

The response of the auditory nerve to acute intracochlear electrical stimulation was studied in 42 guinea pigs. Animals were divided into six groups. The electrode was implanted into the cochlea 1.5 mm in depth, and the cochlea was electrically stimulated with intensities of 216 microA, 432 microA, 648 microA, 864 microA and 1080 microA for six hours. Stimulated with 648 microA or more, the action potential of the auditory nerve altered significantly including the increased N1 threshold, the prolonged latency and the wider waves as compared with the control group. On the other hand, the stimulation with 432 microA or less did not influence the action potential of auditory nerve. The present study indicates that the electrical stimulation with 432 microA or less is relatively safe in the cochlear implantation.