Activation of the auditory cortex by cochlear stimulation in a deaf patient.

We have recorded cerebral electric and magnetic responses to electric stimulation of the auditory nerve in a deaf patient with multichannel cochlear prosthesis. The electric response peaked with a vertex-negative deflection at 65 ms. Clear magnetic responses, coinciding with the vertex potential, were obtained only over the hemisphere ipsilateral to the stimulation; the field pattern indicated activation of the auditory cortex within the Sylvian fissure. The results suggest modification of the central auditory pathways in this patient deaf from early childhood.