Two-Year Follow-up of Isolated Epileptiform Discharges in Autism: An Endophenotypic Biomarker?

CONTEXT: A significant subset of autistic children exhibit abnormal isolated epileptiform discharges (IEDs) in the absence of clinical epilepsy. The etiological significance of such IEDs is under much debate. AIMS: The aim is to study the relationship between IEDs with risk factors, clinical severity, behavioral problems, and social-quotient and follow-up for the occurrence of new seizures. SETTINGS AND DESIGN: This study was a prospective double-blind comparative study of autistic children with and without IEDs. SUBJECTS AND METHODS: All autistic children attending Child Psychiatry Department of tertiary care postgraduate teaching hospital in April 2013 were included in the study. Electroencephalography, risk factors, and clinical severity were assessed. The same cohort of 72 children was followed for 2 years and reassessed. STATISTICAL ANALYSIS USED: Independent sample t-test, Chi-square test, Pearson correlation, and linear by linear association were the statistical methods used. RESULTS: Twenty-four (42%) of the followed up sample exhibited IEDs. 10.52% had converted to clinical seizures within the follow-up period. While there was no difference between risk factors and age at diagnosis between the IED and non-IED groups, there was a significant difference between disease severity, behavioral problems and social quotient between the groups. CONCLUSIONS: IED in a subgroup of autistic children point to more severe illness, severe behavioral problems, and severe social impairment over a 2-year follow-up period. Can IED be considered a neurobehavioral endophenotype in autism?