Abstracts

Rationale: Epilepsy is a frequent comorbidity of autism spectrum disorder (ASD), but the extent to which seizures, epilepsy, and epileptiform phenomena mediate or modify autism is unknown. We set out to describe the burden of epileptiform discharges in a large population of autistic children, with and without epilepsy.Methods: Patients with a clinical diagnosis of autism who underwent overnight video-EEG evaluation for developmental or behavioral regression were retrospectively identified. For each patient we tabulated the burden of epileptiform discharges (ED), including spikes, spike-wave, and paroxysmal fast activity (PFA), as well as demographic factors, and history of epilepsy. Among those who underwent standardized autism diagnostic evaluation, Autism Diagnostic Observation Schedule (ADOS) scores were catalogued. Comparisons of percentages were accomplished with the Fisher exact test.Results: We identified 159 patients (31 girls) who underwent overnight video-EEG monitoring for evaluation of developmental regression and/or characterization of suspected seizures. Of the 52 children who underwent formal autism diagnostic testing, ADOS classification scores were concordant with clinical diagnosis in 51 (98%). 26 (16%) had a history of epilepsy, and 46 (29%) exhibited ED on EEG. In comparison to children without epilepsy, ED were far more frequent among those with epilepsy (58% vs 23%, p= 0.001), and this disparity was evident for spikes (and spike-wave) as well as PFA. When focusing on the ascertainment of frequent ED, there was no difference among those patients with and without epilepsy. See Table 1.Conclusions: As expected, children with autism frequently exhibit abnormal EEGs and at least rare to occasional focal, multifocal, or generalized ED. However, the presence of epilepsy does not explain the substantial observed burden of frequent ED seen in children with autism. Further study is warranted to determine if the burden (frequency and distribution) of ED is associated with severity of autism, and whether treatment of epileptiform discharges alleviates core autistic symptoms.