Familial risk for attention-deficit/hyperactivity disorder and related behaviors in toddlerhood are preliminarily associated with altered frontoparietal development in infancy measured by functional near-infrared spectroscopy

Introduction Attention-Deficit/Hyperactivity Disorder (ADHD) is a common childhood neurodevelopmental disorder associated with impairments across the lifespan. Children with ADHD have been found to have delayed brain maturation. These delays may be present and detectable with functional near-infrared spectroscopy (fNIRS) as early as infancy for children at familial risk for ADHD. The present study examined longitudinal changes in functional connectivity among infants at high and low familial risk for ADHD, and their association with ADHD-related behaviors in toddlerhood. Methods Participants were 44 infants, half at high familial risk for ADHD due to parental ADHD, assessed at 8-10 months and 12-14 months of age. fNIRS was used to measure hemodynamic activation in frontal and parietal regions during a low cognitive load task of attention. In toddlerhood, 18-30 months of age, parents rated ADHD-related behaviors using the Child Behavior Checklist. Results Across the sample, longitudinal fNIRS analyses revealed increased frontal connectivity with a notable leftward shift between timepoints. High-risk children showed greater increases in frontoparietal connectivity relative to low-risk peers, with divergent trajectories observed in left dorsolateral prefrontal cortex and right parietal connectivity. Greater parent-reported attention symptoms were broadly associated with increased frontoparietal connectivity. Discussion Although most findings did not survive corrections for multiple comparisons, these findings suggest that familial ADHD risk and early ADHD-related behaviors may be associated with atypical frontoparietal and frontal network development across the first year of life, highlighting the potential of fNIRS as a tool for identifying early neural markers of ADHD risk that could be used to identify which infants could benefit from early preventative interventions.