The spectrum of electroencephalographic characteristics in children with autistic spectrum disorder at a tertiary care centre

Abstract

There are high rates of epileptiform EEGs in children with ASD without a history of seizures or epilepsy. ASD is associated with a higher risk of epilepsy with prevalence ranging from 5%-46%. The study was conducted to detect the prevalence of EEG abnormalities in ASD patients and to evaluate the spectrum of EEG changes in epileptic and nonepileptic patients with their clinical features and severity of ASD. The study was conducted at the tertiary care centre. A total of 140 cases with ASD, who met DSM V criteria for autism were studied. All the cases were screened with history taking, physical, neurological, and neuropsychiatric evaluation. These children were subjected to psychological testing using the ISAA scoring system. All the studied cases were also subjected to EEG testing. The prevalence of EEG changes (epileptic and non-epileptic discharges) in our study was 45%, with EEG changes seen in 28.44% of cases of ASD without seizure. In ASD cases with seizure, the most common seizure type was generalized tonic-clonic convulsion (GTCS), on the contrary, most common EEG changes were focal epileptiform activity. Most of EEG had shown well-formed background, except for few which were slow for age. The most dominant background rhythm was theta intermixed with delta followed by theta and delta intermixed with alpha in those children with seizures. Whereas, in children without a history of seizure, the dominant rhythm was delta theta alpha and theta delta. This may be due the o large number of EEG recordings being sleep EEG. We will like to hypothesize that the predominant EEG changes in the frontal lobe may have some neuronal link in the pathogenesis of behavior pattern in ASD. We also propose that more detailed study with different types of EEG and with a larger sample size should be done in the future.