Behavioral Characteristics of Children with Comorbid Epilepsy and Autism Spectrum Disorder
It is well recognized that epilepsy is more common among individuals with autism spectrum disorder (ASD) than in the general population, with prevalence estimates varying widely from 2.4 to 46 % compared to 1 to 2 % in the general population. While the co-occurrence of ASD and epilepsy is well established, it remains unclear if there is a causal relationship between the two disorders, or if shared neurobiological pathways are involved. The majority of research in to the relationship between comorbid epilepsy and ASD has focused on general variables including presence of intellectual disability and epilepsy type, yet little is known of the autism phenotype in this population, and how it differs from that of individuals with ASD alone. A few studies have investigated behavioral characteristics in those with ASD and epilepsy and have reported greater social impairment and maladaptive behaviors, yet results have been inconsistent and findings limited. Additional research is needed to fully characterize the autism-epilepsy phenotype as this may help to direct clinical care and assist in understanding the neurobiological basis of these co-existing disorders.
To compare clinical, genetic and neurobehavioral profiles of children with comorbid ASD and epilepsy to those with ASD alone in a clinic based, ethnically and racially diverse population.
100 children with ASD (medical confirmation of diagnosis, completed DSM5 checklist or CARS-2 score verifying autism symptoms and ADOS-2 score in full autism range) were enrolled in the study (50 % Caucasian, 46 % racial or ethnic minority, 4% undisclosed). Eight subjects were diagnosed with epilepsy (history of two or more unprovoked seizures). Each subject underwent a detailed medical history and physical exam and chromosomal micro-array was sent. Participants were evaluated with the following assessments; Social Responsiveness Scale-2 (SRS-2), Vineland-II, PDDBI and either the Mullen Scales of Early Learning or the Stanford-Binet Intelligence Scales. Comparison was made between the ASD alone group (n=92) and those with comorbid ASD and epilepsy (n=8).
There was no significant difference in age, gender, race/ethnicity or presence of micro-array abnormality between groups. Children with ASD and epilepsy were reported to have higher rates of developmental regression, lower average IQ and were more likely to have speech delay. They were noted to have reduced responsiveness on the PDDBI along with decreased frequency of aggressive behaviors. In addition, the ASD/epilepsy group was noted to have greater deficits in social awareness on the SRS-2.
We find that amongst children in a racially and ethnically diverse clinic setting, those with comorbid ASD and epilepsy have a greater degree of cognitive impairment and a specific pattern of behavioral deficits marked by reduced responsiveness and greater deficits in social awareness. Those with ASD and epilepsy have a decreased frequency of aggressive behaviors, possibly related to reduced awareness and responsiveness to their environment. These findings contribute to expanding literature describing the autism/ASD phenotype and the specific challenges faced by this subset of the ASD population.