P.026 Focal DBS of Posterior Cingulate Cortex for Refractory Nonlesional Epilepsy: A Case Report

Abstract

Background: Deep brain stimulation for epilepsy is becoming an effective option for the treatment of refractory epilepsy. This is the case of a 19-year-old male patient who has had refractory seizures since 2.5 years old. Seizures occur up to 100 times per day, including gelastic, complex partial, and generalized tonic-clonic types. Methods: Continuous video-EEG monitoring, technetium 99 m ECD SPECT, PET-CT and 3T MRI are used for localization. Depth electrodes are implanted in right frontal orbital, cingulate and lateral frontal regions. Results: Video-EEG records 79 seizures arising from the right frontocentral region. Clinically, patient assumes a fencing posture, with left arm extension. Some seizures undergo secondary generalization. SPECT reveals subtle asymmetric hyperperfusion in right mesial frontal area, while PET-CT and MRI do not show focal lesion(s).Stereo-EEG recording and stimulation confirm seizure onset and trigger zone in the premotor cingulate posterior region. Treatment with stimulation in this region at 130-150 Hz, 4-5 mA, and pulse duration 0.1 ms reduces seizure frequency from 100/day to 3/week. Seizures last only 2-3 seconds, without postictal confusion leading to improvements in neuropsychological function. AED dosages are not reduced. Conclusions: Successful intracranial EEG localization of otherwise non-lesional non-resectable seizure focus permits the use of deep brain stimulation that effectively reduces refractory seizure frequency.