Oculomotor Function in Children and Adolescents with Autism, ADHD or Co-occurring Autism and ADHD.

Researchers studied eye movements in over 400 children with autism, ADHD, or both conditions. They found that children with both autism and ADHD had less accurate eye movements, while autistic children made more corrective eye movements when following moving objects. These differences in eye movement patterns might help us better understand how autism and ADHD affect the brain and could potentially assist with diagnosis in the future.

This large multi-site study examined eye movement patterns in 405 Australian children and adolescents (ages 4-18) with autism, ADHD, co-occurring autism+ADHD, or typical development. Confirmatory analyses included samples from UK and USA sites. Using four different eye-tracking tasks, researchers found that children with both autism and ADHD showed increased variability in eye movement accuracy compared to neurotypical children. Autistic children demonstrated more catch-up eye movements during pursuit tasks.

These findings suggest that specific eye movement differences may be unique to those with co-occurring autism and ADHD, potentially offering insights into the neurobiological underpinnings of these conditions and their overlap.

Eye movement assessment may offer objective biomarkers for understanding autism-ADHD comorbidity. These findings could inform future diagnostic approaches and help clinicians better understand the neurobiological basis of co-occurring conditions, potentially leading to more targeted interventions.

The abstract does not specify methodological limitations, control variables beyond age, sex and family, or potential confounding factors. No discussion of measurement reliability, participant selection criteria, or generalizability constraints is provided.

Oculomotor characteristics, including accuracy, timing, and sensorimotor processing, are considered sensitive intermediate phenotypes for understanding the etiology of neurodevelopmental conditions, such as autism and ADHD. Oculomotor characteristics have predominantly been studied separately in autism and ADHD. Despite the high rates of co-occurrence between these conditions, only one study has investigated oculomotor processes among those with co-occurring autism + ADHD. Four hundred and five (n = 405; 226 males) Australian children and adolescents aged 4 to 18 years (M = 9.64 years; SD = 3.20 years) with ADHD (n = 64), autism (n = 66), autism + ADHD (n = 146), or neurotypical individuals (n = 129) were compared across four different oculomotor tasks: visually guided saccade, anti-saccade, sinusoidal pursuit and step-ramp pursuit.

Confirmatory analyses were conducted using separate datasets acquired from the University of Nottingham UK (n = 17 autism, n = 22 ADHD, n = 32 autism + ADHD, n = 30 neurotypical) and University of Kansas USA (n = 29 autism, n = 41 neurotypical). Linear mixed effect models controlling for sex, age and family revealed that children and adolescents with autism + ADHD exhibited increased variability in the accuracy of the final saccadic eye position compared to neurotypical children and adolescents. Autistic children and adolescents demonstrated a greater number of catch-up saccades during step-ramp pursuit compared to neurotypical children and adolescents. These findings suggest that select differences in saccadic precision are unique to autistic individuals with co-occurring ADHD, indicating that measuring basic sensorimotor processes may be useful for parsing neurodevelopment and clinical heterogeneity in autism.