Childhood absence epilepsy in patients with benign focal epileptiform discharges

Few reports are available of ictal recordings in patients with benign focal epileptiform discharges. The study objective was to estimate the frequency of such recordings and to describe their clinical and electrophysiologic presentation. We performed a retrospective chart review of all patients undergoing routine electroencephalography (EEG) with video during a 10-year period. Among 214 patients with benign focal epileptiform discharges, 5 patients were identified with recorded EEG seizures (2.3%). Epilepsy syndromes included one case of benign focal epilepsy of childhood, three cases of childhood absence epilepsy, and in one case the patient presented with both. Only 1 of the 214 patients (0.4%) had a seizure characteristic of benign focal epilepsy of childhood. A literature review revealed the coexistence of childhood absence and benign focal epilepsy of childhood or benign focal epileptiform discharges within the same patient. These findings suggest that benign focal epilepsy of childhood seizures are rarely recorded during routine EEG, probably because seizures occur during the early morning part of the sleep cycle, which may differ from the brief nap during routine EEG. There was concurrence of generalized spike and wave discharges in these patients. It is unclear whether this is related to a common pathophysiologic factor.