Description

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by social communication deficits and restricted and repetitive behaviors. Symptoms of ASD emerge in the first years of life and can be reliably identified during the second year. Although no longer required for an ASD diagnosis, language delays or atypical emergence of language skills are common in children with ASD. Early language abilities are among the best predictors of later functional outcomes in children and adults with ASD. However, little is known about early atypical brain organization in ASD and language abilities in young children with ASD.This study examines links between brain connectivity patterns, especially between brain regions known to support language processing, and language skills assessed in preschoolers with ASD. The current study utilizes functional MRI data acquired during natural sleep, in combination with clinical and behavioral data collected from toddlers and preschoolers with ASD and typically developing (TD) young children participating in the longitudinal SDSU Toddler MRI Project examining early brain markers of ASD. The cohort includes 24 children with ASD (7 female, 17 male) and 17 TD children (6 female, 11 male) who were between 16 and 51 months of age (mean age 28.68±8.8 months) at their first study visit, and between 36 and 68 months (mean age 49.83±11.4 months) at the second study visit (average 21 months between visits). Changes in language abilities were assessed with the ADOS, Mullen, and Vineland. Developmental and language skills were assessed in all (ASD and TD) participants with the Mullen Scales of Early Learning (MSEL). Results indicated that inter-hemispheric connectivity between several canonical language regions is associated with later expressive language skills in children with ASD. Namely, greater connectivity between contralateral language regions (indicating lower laterality or specialization for language) at toddler years was associated with lower language skills at preschool years. Because decreased hemispheric laterality of language function (observed among toddlers with ASD in our cohort) is indicative of less mature brain organization, these findings suggest a link between less mature brain connectivity patterns in the first years of life and delayed language skills in preschoolers with ASD.