ELECTRICALLY-EVOKED AUDITORY BRAIN-STEM RESPONSE BY DIRECT ELECTRICAL-STIMULATION TO THE COCHLEAR NERVE IN ACOUSTIC NEUROMA PATIENTS

The electrically evoked auditory brainstem response (EABR) was recorde d by direct electrical stimulation of the cochlear nerve in 8 acoustic neuroma patients. The EABR by electrical stimulation of the cochlear nerve at the fundus of the internal auditory canal was almost similar to those previously reported from cochlear implant patients in wavefor m morphology and wave latencies. However, the wave corresponding to wa ve II in human auditory ABR was not recorded in the EABRs by stimulati on of the distal part of the intracranial cochlear nerve. These result s suggest that the cochlear nucleus does not contribute to the generat ion of wave II in ABR.