Abstracts

Rationale: To investigate the cortical EEG correlates of frontotemporal EEG spikes, and in so doing, further understand their clinical implications of seizure-induced epileptic progression and surgical outcome in patients with temporal lobe epilepsyMethods: We retrospectively included 17 patients with medically refractory mesial temporal lobe epilepsy who had frontotemporal EEG spikes and underwent simultaneous scalp and intracranial EEG recording during presurgical evaluation. We studied the cortical EEG correlates of frontotemporal scalp EEG spikes and the relationship of interictal and ictal discharges between frontal and temporal cortex in these patients. Their surgical outcome was determined according to Engel s classificationResults: Temporal ECoG spikes and seizures were recorded in all patients. Frontal ECoG spikes synchronized with temporal ECoG spikes were observed in all 16 of 17 patients. Temporally independent frontal ECoG spikes were recorded in 10 patients and were only recordable in 3 patients on scalp EEG. Independent frontal seizure foci were recorded in 2 patients. During 1-year postoperative follow-up, 8 of 16 (50%) patients had Engel class I surgical outcomeConclusions: Our data demonstrated that frontotemporal EEG spikes commonly have dependent and independent spike sources in the frontal cortex that occasionally generates spontaneous frontal seizures. Frontotemporal spikes mark seizure-induced epileptic progression from temporal to frontal cortex and may predict poor surgical outcome in patients with TLE