Atypical EEG in autism spectrum disorder: Comparing a dimensional and a categorical approach

Myriad studies have found group differences in neural dynamics between people with and without autism spectrum disorder (ASD). However, the extent to which variation in neural dynamics is related to variation in the autism phenotype across the population is not known. Here we measured behavioral characteristics of autism alongside intertrial phase coherence (ITC) and multiscale entropy (MSE) computed from EEG in order to address this question. Data were obtained from 99 adults, 38 of whom had an ASD diagnosis. Phenotypic information was obtained from the Social Responsiveness Scale (Revised), the Repetitive Behavior Questionnaire, the WHO Adult ADHD Self-Report Scale Screener, and the Beck Anxiety Inventory (Trait version). ITC and MSE were computed from EEG recorded during visual stimulation and eyes-closed rest. We found no evidence to suggest that population variance in autistic traits is underpinned by variance in neural dynamics, despite finding that ITC and MSE are more likely to be reduced in people with ASD than in those without. We conclude that there are likely to be multiple neural profiles underpinning ASD, and suggest that while individual differences in the autism phenotype exist across the population, their distribution is not underpinned by individual differences in neural dynamics.