Prevalence of Autism Spectrum Disorders and its association with epileptiform activity among children with Intellectual Disability in a tertiary centre
Introduction: The prevalence of ASD’s (Autism Spectrum Disorders) has increased in recent years. ASD is known to be comorbid with medical conditions such as seizures. However, relatively less research has focussed on epileptiform activity in the absence of clinical seizures and its role in ASD. This study aimed to study the prevalence of ASD among those with Intellectual disability in a tertiary clinic and also the prevalence of epileptiform activity among those who were diagnosed to have ASD.
Methodology: This study screened 223 children with Intellectual Disability for ASD using Indian scale for assessment of Autism (ISAA) after IEC approval and informed consent from caretaker. Also, for those children who were diagnosed to have ASD, Behavior Problems checklist (BPI) was administered to screen for behavioural problems, details about medical comorbidities and regression were noted. EEG was then performed to screen for epileptiform activity.
Results and discussion: Our study showed that 17.04% of those referred for assessment of IDD had comorbid ASD. Those with IDD and autism had significantly more behavioural problems than those without autism. Individuals with moderate and severe autism had more behavioural problems than those with mild autism which was statistically significant in ANOVA (p= 0.0005). 50% of the total number of individuals with ASD had GI problems, mainly diarrhoea. Using multiple linear regression, behavioural problems could be significantly predicted by IQ scores, autism scores and age. In our study, though only 5 had history of seizures, the prevalence of epileptiform EEGs in those with ASD was 52.6% (n=20). Those with epileptiform activity had significantly more behavioural problems than those without epileptiform activity (p=0.05).In addition, these individuals had a higher history of regression in language or social skills (p=0.02). When a logistic regression was performed to predict odds of having epileptiform activity in those with autism, behavioural problems and autism scores, but not IQ scores or age had higher odds of predicting epileptiform activity.
Conclusion: Majority of children with regression had epileptiform EEG in the absence of seizure. Connectivity deviations as a part of neurodevelopmental abnormality may be translating into increased cortical excitability causing epileptiform activity. Large scale studies are warranted in this area.