The absence of interictal spikes with documented seizures suggests extratemporal epilepsy

Purpose: To determine the demographic and clinical characteristics of patie nts who have documented epileptic seizures on long-term video-EEG monitorin g who do not have interictal spikes. Methods: The records of 1,223 monitoring studies from 919 patients who unde rwent noninvasive long-term video-EEG monitoring were reviewed. in 28 patie nts (3.0% of monitored patients, 4.4% of patients with electrographic evide nce of epilepsy), no interictal spikes were found despite the occurrence of at least one recorded electrographic seizure. The demographic, medical, ne uropsychological, and EEG data of these patients were compared with those o f 28 matched control patients with documented interictal spikes. Results: Extratemporal seizures were significantly more frequent in the pat ients with at least one recorded epileptic seizure but without interictal s pikes compared with patients with epileptic seizures and interictal spikes (p = 0.031). The only other significant difference between the groups (p = 0.016) was a later age at seizure onset (18.3 vs. 10.7 years) for the patie nts without interictal spikes. Age at evaluation, gender, handedness, clini cal seizure type, family history of epilepsy, history of febrile seizures, neuropsychological testing, and neurologic and psychiatric history did not differ between the two groups. Conclusions: In patients with documented epilepsy without interictal spikes on EEG monitoring, the possibility of an extratemporal focus should be con sidered.