Abstracts

Rationale: The prevalence of epilepsy is approximately 25% in adolescents with autism spectrum disorders (ASD). Interictal epileptiform discharges can interfere with normal neural processing. However, studies on video EEG data on these patients remain limited. This study aims to characterize interictal and ictal video EEG findings of patients with epilepsy and ASD. Methods: We retrospectively reviewed clinical records and video EEG studies of 53 pediatric and adult patients (age 5 - 45 years) with ASD diagnosed by DSM-IVR as well as ADOS or ADI-R. All patients were cared for at the Saint Barnabas Medical Center. Using a standardized assessment methodology, we analyzed prolonged video EEG studies (24-96 hours) and characterized the interictal non-epileptiform abnormalities, epileptiform abnormalities, and ictal findings. Seizures were characterized by onset, ictal pattern, duration, clinical description, and presence of postictal suppression. Results: Video EEG studies were abnormal in 50 of 53 records. Based on clinical records and prolonged video EEG findings, 40% of patients have focal epilepsy, 30% have generalized epilepsy, 25% have both a focal and generalized epilepsy and the diagnosis was unclear in 5%. Interictal nonepileptifom abnormalities occurred in 40% of studies: 52.2% generalized slowing, 17.4% focal slowing (temporal > frontal, parietal, occipital), and 30.4% both generalized and focal slowing. Interictal epileptiform abnormalities occurred in 85% of the studies: 22% focal epileptiform discharges, 27% multifocal epileptiform discharges, 29% generalized epileptiform discharges, and 22% both generalized and focal epileptiform discharges. 9 video EEG studies record a total of 24 seizures with onsets that are generalized (13), lateralized (8), focal (2), or nonlocalizable (1). Two additional video EEG studies show numerous generalized myoclonic and absence seizures. Duration of seizures was 9 seconds - 120 seconds. Clinically, there are 9 generalized tonic clonic, 4 tonic, 4 hypermotor, 3 focal, 3 atonic, and 1 subclinical seizure recorded. Postictal suppression was present in 2 of the generalized tonic clonic seizures and in one case lasting 63 seconds. Conclusions: The presence of epilepsy represents an important endophenotype in the ASD population. Determining the nature of the interictal and ictal abnormalities and their relationship to the ASD phenotype and genotype may help advance our understanding of ASD and epilepsy and guide treatment.