The role of epileptiform activity in neural circuitry and how that influences sleep, behavior, and cognition in autism spectrum disorders (ASD) is unclear. From a theoretical standpoint, epileptiform activity could have a significant disruptive effect on circuit function, thereby contributing to sleep problems, behavioral issues, and cognitive dysfunction.
To define the relationship of epileptiform activity to sleep, behavior, and cognition in a previously well characterized cohort of children with ASD and normal IQ, and free of medications and seizures.
Children with a diagnosis of ASD (autism, Asperger disorder, or PDD-NOS) confirmed by Autism Diagnostic Observation Schedule (ADOS), age 3-7 years, were enrolled. Upon entry into the study, parents completed the Repetitive Behavior Scales (RBS), Children’s Sleep Habits Questionnaire (CSHQ), and Child Behavior Checklist (CBCL). Subjects also underwent IQ and language testing. Two nights of overnight polysomnography with 21-channel EEG was also performed in each child.
A total of 52 children completed the study , including 13 typically developing age-matched children and 39 children with ASD. Ten of 39 children had an epileptiform EEG compared to one of 13 typically developing children (26% vs 7%, p<0.01; Fisher-exact test). Most epileptiform EEGs had epileptiform activity in frontal, central, or temporal leads. On the CBCL, only the aggression score and externalizing score were significantly increased those with ASD and epileptiform EEGs compared to those with ASD alone and no epileptiform EEGs (p<0.05). On the RBS, there was a non significant trend (p=0.07) to enrichment of stereotyped behaviors in ASD with epileptiform EEG group while increased repetitive behaviors were detected in the ASD alone without epileptiform EEG group. Sleep latency on night two was significantly decreased in those with ASD and epileptiform EEGs compared to those with ASD alone and without epileptiform EEGs (p<0.05). Groups showed no significant differences in age, CHSQ, IQ measures, and scores on Peabody Picture Vocabulary testing.
While this work requires replication in larger samples and a broader ASD population, our findings suggest that children with ASD, even if medication free, seizure free, and with a normal IQ, have epileptiform EEGs in the central, frontal, and temporal regions. Furthermore, epileptiform activity in this group of children with ASD was associated with differences in mood, sleep parameters, and indices of repetitive/restricted behaviors among the ASD groups. Interventional studies will be necessary to determine the directional relationship between epileptiform activity and sleep and behavior.
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