Risk of autism spectrum disorder in children with unprovoked seizures in the first year of life – A population-based study

Background: A subgroup of children diagnosed with autism spectrum disorder (ASD) has a history of unprovoked seizures in the first year of life.

Objectives: To study the association between unprovoked seizures in the first year of life and ASD.

Methods: Children diagnosed with seizures in the first year of life during the period 1982-1998 were identified in hospital records of all the pediatric in-patient facilities in Iceland. Of 121 children five had died and one lived abroad. The parents of 115 children were invited into a study of possible ASD. The Social Communication Questionnaire was used as an initial test of autistic behaviors, followed by the ADI-R and the ADOS and/or the CARS. Prevalence of ASD as the percentage of cases and exact 95% confidence intervals (CI) were calculated. Logistic regression was used to calculate odds ratio (OR) and 95% CI.

Results: Ninety-five children participated (82.6%). Of these, 17 (17.9%) had infantile spasms (IS) and 78 (81.1%) had other types of seizures. Thirteen children or 13.7% (95% CI, 7.5-22.3) had ASD, eight females and five males. Six of the children with ASD had IS, and seven had other types of epilepsy. All but one had intellectual disability (ID), and six had profound ID (IQ<20). The OR was 1.55 (95% CI, 0.33-7.37) for children with IS compared to those without IS, adjusted for symptomatic origin of seizures. The OR was 8.73 (95% CI, 1.88-40.54) for children with symptomatic origin of seizures compared to those with non-symptomatic seizures, adjusted for IS.

Conclusions: High prevalence of ASD was found in children with a history of unprovoked seizures in the first year of life. There was an overrepresentation of the female gender and ID in the ASD group. The symptomatic origin of seizures increased the risk of ASD, rather than IS.