P.667 Early motor development predicts clinical outcomes of siblings at high-risk for autism: insight from an innovative motion-tracking technology

Abstract

Although there is little overlap in core diagnostic criteria for ADHD and Autism Spectrum Disorder (ASD), ASD symptoms are estimated to co-occur in children with ADHD in 20–50% of cases. As motor control deficits are common to both disorders, we investigated the impact of ASD symptoms on ocular motor control in children with Attention Deficit Hyperactivity Disorder-Combined Type (ADHD-CT), using a cued saccade paradigm sensitive to cerebellar ocular motor impairment in ASD. Basic saccade metrics (latency, velocity and accuracy), trial-to-trial variability, and main sequences relationships (saccade velocity for a given amplitude) were assessed, for 14 males with ADHD-CT and 14 typically developing (TD) males (aged 8–14, IQ > 80). Our results revealed that saccade profiles of the ADHD-CT group showed a pattern of hypermetria and altered main sequence. As the cerebellum is crucially involved in the regulation of saccade parameters, we propose that this pattern of deficit in ADHD-CT is consistent with the widely reported morphological abnormalities in ocular motor vermis (cerebellar lobules VI-VII) in ADHD-CT and ASD.