SUBDURAL RECORDING OF BEREITSCHAFTSPOTENTIAL IS USEFUL FOR FUNCTIONALMAPPING OF THE EPILEPTOGENIC MOTOR AREA - A CASE-REPORT

A 26-year-old man with intractable focal motor seizure beginning with tonic contraction of the left orbicularis oculi muscle had prolonged E EG monitoring with subdural grid electrodes placed over the right peri rolandic cortex. Electrical stimulation of the cortex with implanted s ubdural electrodes showed a relatively low threshold for afterdischarg es (ADs) but could not disclose the motor area for the left upper face where or near where the epileptogenic area was expected to be present . Bereitschaftspotential recorded from the subdural electrodes in asso ciation with self-paced voluntary blink (eyelid closing) disclosed the motor area specifically related to voluntary movements of the left up per face, which was most likely buried in the sulcus. This observation suggests that recording of Bereitschaftspotential from subdural elect rodes is useful for mapping the motor cortex, especially in patients w ith focal motor seizure with low threshold for ADs to electric stimuli .