Absence of seizures despite high prevalence of epileptiform EEG abnormalities in children with autism monitored in a tertiary care center.

Summary: Purpose: Children with autism are commonly referred for video-EEG monitoring to determine the precise nature of their seizure-like events. Methods: We studied 32 children with autism by using continuous video-EEG telemetry (VEEG) monitoring at a tertiary care referral center. Results: Of the 32 total patients, 22 were primarily referred for seizure evaluation and 10 for 24-h interictal EEG recording. Studies in two additional patients were prematurely terminated because of intolerance (they are not included in the analyses). The median monitoring duration was 1 day (range, 1–7 days). Of 22 patients referred for seizure evaluation, 15 had recorded events, but none was an epileptic seizure; the other seven patients had no recorded events. Interictal epileptiform EEG abnormalities were detected in 19 (59%) of 32 patients. These abnormalities included focal sharp waves (in eight patients), multifocal sharp waves (in six patients), generalized spike–wave complexes (in 11 patients), and generalized paroxysmal fast activity/polyspikes (in two patients). Focal/multifocal and generalized epileptiform abnormalities coexisted in six patients. Notably, 11 (73%) of the 15 patients with nonepileptic events had interictal epileptiform EEG abnormalities. Conclusions: Video-EEG evaluation of children with autism reveals epileptiform EEG abnormalities in the majority. However, many recorded seizure-like events are not epileptic, even in children with epileptiform EEG abnormalities.