Abstracts

RATIONALE: Children with autistic spectrum disorder (ASD) are often evaluated with prolonged Video-EEG (VEEG) recordings to determine if specific behavioral manifestations are seizures. VEEG is also done to evaluate the presence of interictal epileptiform activity, in the absence of clinical seizures. The significance of this interictal abnormality, as a possible contributing factor for abnormal behavior or poor language development, is not fully understood. We studied the relationship between the incidence of interictal epileptiform discharges and seizures in children with ASD.
METHODS: We reviewed 55 patients, diagnosed with ASD (ages ranging between 2.5 and 10 years, mean 5.9 years, 46 males and 9 females) who underwent overnight or prolonged VEEG for 16 to 72 hours. ASD was diagnosed using the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) criteria. The data was analyzed for clinical spells with electrographic changes. Other electrographic abnormalities noted included frequency of epileptiform activity, spatial distribution of discharges and other non-specific abnormal findings (i.e frontal arousal rhythm, focal slow waves etc.).
RESULTS: Frequent epileptiform discharges were seen in 20 of 55 individuals (36.3%), 9 (16.4%) had infrequent or rare discharges, and 26 (47.3%) had no epileptiform discharges. Thirteen of the 20 children (65%) with frequent discharges had a history of epilepsy, and 10 of the 13 had clinical events with electrographic correlate during VEEG monitoring. Thirty-five had rare or no epileptiform discharges. Four of these 35 children (11%) had a history of prior seizures, and 2 had captured electro-clinical events during VEEG. The incidence of epileptiform discharges correlated with seizures (p[lt]0.01). Electrical status epilepticus during sleep (ESES) was captured in 2 children (3%), who had no clinical events during VEEG. Epileptiform discharges were recorded over the frontal, central and/or temporal regions in 25 children. 3 of the 25 children also had parietal or occipital discharges and one child had occipital discharges only. Other EEG findings did not correlate with seizure history.
CONCLUSIONS: There was a significant correlation between a high incidence of epileptiform discharges and seizures in ASD patients. Most focal epileptiform discharges were localized in the perirolandic and perisylvian regions. There have been conflicting reports about the frequency or significance of epileptiform activity seen in ASD children. In our study of objectively defined ASD children, during overnight or more prolonged VEEG recordings, frequent epileptiform activity was seen in a minority of children without a seizure history. None of those children had electro-clinical seizures during monitoring.