Original articleAutism and epilepsy: A retrospective follow-up study
Introduction
Many studies [1], [2], [3], [4], [5], [6], [7], [8] have pointed out a close relationship between autism and epilepsy. The reported rate of epilepsy in autism has varied from 12.6% to 39.2%. Since autism is defined by a particular behavioral phenotype, not by specific etiology or pathophysiology, all the studies mentioned above included individuals with “symptomatic” or secondary autism, i.e., West syndrome, tuberous sclerosis, fragile-X syndrome that had already exhibited epileptic seizures before the diagnosis of autism.
So-called idiopathic or primary autism, which exhibited no major complications before the diagnosis, is also well-known as one of the risk factors for epilepsy. This retrospective follow-up study aimed to clarify the characteristics of epilepsy in idiopathic autism, i.e., onset of seizure, seizure types, EEG findings and epilepsy outcome, and the differences as a group between autism with and without epilepsy.
Section snippets
Methods
The subjects of this study consisted of children referred to the Kanagawa Day Treatment & Guidance Center for Children for the evaluation of development, diagnosis and treatment of challenging behaviors. The author, one of the child neurologists at the center, checked up all subjects in the ordinary clinical setting and followed up almost every year from their first visit to adulthood. These subjects were selected from those individuals re-diagnosed by the author as having one of pervasive
Results
The subjects of this study consisted of 130 individuals with autistic disorder or atypical autism diagnosed in childhood (males, 104; females, 26). Their first visits ranged from 1 to 14 years of age (Median = 4 years). All but four subjects were followed up over 10 years by the author from their first visit. The median age of the subjects was 21 years (range: 18–35) at the time of this review.
Thirty-three out of the 130 patients (25%) developed epilepsy during the follow-up period. The
Discussion
This study has three unique points: first, the study focused on the relationship between “idiopathic” autism and epilepsy, second, this is the longest and largest retrospective follow-up study ever performed, and third, this study based on a huge number of routine EEG records (1165 records) obtained during the follow-up period.
The reported incidence of epilepsy in autistic individuals has varied from 13% to 40%. The occurrence of epilepsy in this study is 25%, which appears to be relatively
Acknowledgment
This paper was presented in the 10th International Child Neurology Congress, Montreal, Quebec, in June 2006.
References (13)
- et al.
Seizure disorders in autism
J Am Acad Child Adolesc Psychiatry
(1990) - et al.
Epilepsy in adolescents and young adults with autistic disorder
Brain Dev
(2000) Infantile autism with speech loss before the age of thirty months
J Am Acad Child Psychiatry
(1985)- et al.
The incidence of seizures among children with autistic symptoms
Am J Psychiatry
(1979) - et al.
Epilepsy in autism and autisticlike conditions: a population-based study
Arch Neurol
(1988) - et al.
Autistic and dysphasic children. II. Epilepsy
Pediatrics
(1991)