Brain Stem Responses Evoked by Cochlear and Vestibular Nerve Stimulation

Abstract

Electrically and acoustically evoked brain stem responses were compared in guinea pigs. Electrical stimulation of the cochlea was made by two electrodes, one to the scala tympani of the basal turn, and the other to the scala media of the third turn. Six hundred consecutive responses were averaged by a computer. Responses evoked by the direct stimulations of the cochlear, vestibular and facial nerves were respectively recorded by the same procedure.
Electrical stimulation of the cochlea could evoke a response with successive five to six waves within 8 msec, of which the fourth wave was most prominent and stable. This response was similar to that one elicited by auditory stimuli. Direct stimulation of the cochlear nerve could evoke the same pattern of the response. On the other hand, stimulations of the vestibular and facial nerves could evoke definitely different responses, or even could evoke nothing.