Pervasive Rightward Asymmetry Shifts of Functional Networks in Autism Spectrum Disorder

IMPORTANCE Autism spectrum disorder (ASD) is a brain-based pervasive developmental disorder, which—by growing consensus—is associated with abnormal organization of functional networks. Several previous studies of ASD have indicated atypical hemispheric asymmetries for language. OBJECTIVE To examine the asymmetry of functional networks using a data-driven approach for a comprehensive investigation of hemispheric asymmetry in ASD. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study involved 24 children with ASD and 26 matched typically developing children at San Diego State University and the University of California, San Diego. Data from 10 children had to be excluded for excessive motion, resulting in final samples of 20 participants per group. MAIN OUTCOMES AND MEASURES Asymmetry indices of functional networks identified from independent component analysis of resting-state functional magnetic resonance imaging data. RESULTS Temporal concatenation independent component analysis, performed separately in each group, showed significant group differences in asymmetry indices for 10 out of 17 functional networks. Without exception, these networks (visual, auditory, motor, executive, language, and attentional) showed atypical rightward asymmetry shifts in the ASD group. CONCLUSIONS AND RELEVANCE Atypical rightward asymmetry may be a pervasive feature of functional brain organization in ASD, affecting sensorimotor, as well as higher cognitive, domains.