Abstracts

Rationale: Autism Spectrum Disorders (ASD) affect one out of 152 children in the U.S. ASD has a distinct neuropsychological profile including pervasive delay in language and social development and presumed genetic heterogeneity. Approximately 25% of children with ASD have interictal epileptiform discharges (EDs) on their EEG with a higher prevalence of seizures. In an ongoing attempt to determine the incidence of epilepsy in ASD patients with abnormal EEGs, we comprehensively evaluated eight ASD children with interictal EDs using DSM IV criteria. Methods: Eight children (seven males, one female; age: 3-10 years) received a complete neurological evaluation. All underwent an EEG using the International 10-20 Electrode Placement System. Three underwent video EEG monitoring. The EEG was evaluated for localization, laterality, and morphology. Seven of the eight underwent high resolution chromosomal testing, Fragile X testing, complete blood counts and comprehensive metabolic testing (electrolytes, blood urea nitrogen, bicarbonate, liver function studies, serum amino acids and urine organic acids). All children underwent magnetic resonance imaging (MRI) of the brain using an epilepsy protocol with oblique, thin-cut, coronal fluid attenuation inversion recovery (FLAIR) sequences. Six children underwent detailed neuropsychological evaluations which were adapted to each child but included the Gilliam Autism Rating Scale (GARS), Child Behavior Checklist, and/or Vineland Adaptive Behavior Scales.Results: All eight children had interictal EDs. Five children had para-sagittal EDs (two left hemisphere, two right hemisphere, and one bilateral). Two had left temporo-parietal EDs. One child had rare, right mid-temporal discharges with a predominance of left para-sagittal EDs. One child had generalized EDs. Two out of eight had a history of seizures consistent with partial events. One child with seizures had a normal MRI and left para-sagittal and rare, right mid-temporal EDs; while the other had mild diffuse atrophy with marked atrophy of the left temporal and parietal lobes and EDs in the same region. The remainder of the children had normal MRIs. Genetic and metabolic testing were normal in all children. All of the children demonstrated low adaptive skills, poor emotional and social reciprocity and/or a high probability of autism on neuropsychological testing. Conclusions: In this ongoing study, two of eight children (25%) with ASD and interictal EDs had epilepsy. Both children had partial seizures consistent with the interictal EEG pattern. Although our case number is small, the preliminary data implies that the epilepsy rate among ASD children with interictal EDs is relatively low. Furthermore, one of those children appears to have both ASD and epilepsy as a result of focal brain injury (which represents a distinct subset of ASD patients). Thus far, neuropsychological data imply low adaptive, verbal and social skills in ASD patients and interictal EDs regardless of the presence of seizures. Continued investigation is warranted.