ccdc453872a80a9612d3654c2fd96ea4During the NDC Symposium-Neurobiology of Disease in Children: Session I: Clinical Aspects at the 43rd Annual Child Neurology Society Meeting, held in Columbus, OH, October 22-25, Roberto Tuchman, MD, delivered a presentation that looked some of the mechanisms shared by epilepsy and autism spectrum disorder (ASD) that lead to overlapping symptoms, and reviewed current research on the prevalence of co-morbid epilepsy and ASD in children.

Tuchman is the director of the Brain Development Network at Miami Children’s Hospital Dan Marino Center, and professor I the Department of Neurology and Psychiatry & Behavioral Health at Herbert Wertheim College of Medicine, FIU.

He noted that ASD-epilepsy co-diagnosis is fairly common, with one study using data from the nationwide Norwegian Patient Register (n=731,318) found that 11.2% of children diagnosed with ASD also had epilepsy, and 6.1% of children with epilepsy had a co-existing diagnosis of ASD. Another study revealed that intellectual disability (defined for the study as an IQ<70) is a clinical feature shared by ASD and epilepsy. In that study (a meta-analysis of 24 studies) researchers found that nearly 1 in 5 (21.4%) patients with ASD and intellectual disability also had epilepsy, compared with only 8% of patients with ASD and no intellectual disability.  

Another pooled meta-analysis of 16 studies measuring rates of epilepsy in ASD found similar results. One group of 9 studies in which more than 70% of participants (n=1,583) had IQ<70 and were age 12 or older at follow up had an estimated epilepsy prevalence of 23.7%. Another subset of studies that included a smaller percentage of patients with intellectual disability had an estimated epilepsy prevalence of only 8.9%.

A study published by Tuchman and colleagues in Pediatrics in 1991 found the highest cumulative risk of epilepsy by age 10 (67%) in children with ASD, severe intellectual disability, and cerebral palsy. In children with ASD and severe intellectual disability, the cumulative risk of epilepsy by age 10 was 27%. A study by Bolton et al. in The British Journal of Psychiatry which looked at a cohort of 150 individuals with ASD from 1950 to 1985 found 22% of participants had epilepsy, with a mean age of seizure onset of about 13 years old (and the majority occurred after age 10). The authors reported that “epilepsy was more common in those with intellectual disability, low levels of language, and in females. Presence of epilepsy in the proband was a significant predictor of a relative having the broader autism phenotype.”

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