P54-S Somatosensory and motor phenomena elicited by electrical stimulation of hippocampus: insight into the ictal network

Abstract

Background Direct electrical stimulation of the cortex elicits responses according to the physiology of the stimulated area. In patients with drug resistant epilepsy evaluated for surgical therapy, this method is used for mapping the eloquent cortex and for triggering the patients’ habitual seizures, using intracerebral electrodes. Up to 11% of patients with mesial temporal lobe epilepsy have somatosensory aura, although these structures do not have any somatosensory physiological representation. Material and methods We present the case of a patient with left mesial temporal lobe epilepsy who had somatosensory auras on the right side. Direct electrical stimulation of the left hippocampus, at 50 Hz, elicited the somatosensory auras, while stimulation at 1 Hz elicited myoclonic jerks time-locked to the stimulus. Results and conclusions These unusual responses to cortical stimulation suggest that in patients with epilepsy aberrant neural networks are established, which have an essential role in ictogenesis.