Restricted Repetitive Behaviors in Adolescent Males with Autism: Volatility in Brain Functional Connectivities

This paper studies subtypes of restricted, repetitive and stereotypical behaviors (RRBs) in adolescent males with autism spectrum disorder (ASD) from the viewpoint of the dynamics of brain functional connectivities (FCs). Data from the ABIDE-II repository and Repetitive Behavior Scale-Revised (RBS-R) metrics are used to form two ASD groups with tightly controlled demographics; one comprises subjects with scores above threshold for the self-injurious behaviors (SIBs) subscale, and the other subjects with scores below threshold for SIBs, but above threshold for at least one of the other subscales (stereotyped, compulsive, ritualistic, insistence on sameness, restricted interests). The dynamics of the coherence for FCs across distinct frequency bands are compared against matched controls, using a novel volatility measure computed in time-frequency space. We find statistically significant differences, on average, in the volatility of a relatively small set of FCs, most mapping to either the default mode network or the cerebellum, in the mid- and high-frequency bands, and yielding higher volatility in subjects with high levels of SIBs. Results suggest a distinct underlying profile for SIBs involving multiple brain regions associated with rewards and emotions processing. The work contributes to the identification of neural substrates potentially underlying behavioral subtypes, and may help target interventions.