Resting and functional pupil response metrics indicate features of reward sensitivity and Autism Spectrum Disorder in children

Altered motivational drives and aberrant reward system function may contribute to the social impairments observed in autism spectrum disorders (ASD). Pupil metrics have been highlighted as peripheral indicators of autonomic arousal and reward system function, specifically noradrenergic and dopaminergic activity that influence motivational drive states. However, research on individual differences in the neurobiological correlates of reward responsivity and clinically relevant features associated with ASD is sparse. The goal of the current study was to examine the relationship between measures of sensitivity to punishment and reward, ASD features, and resting as well as functional pupil response metrics across a clinically heterogeneous pediatric sample. We assessed whether quantitative features of reward sensitivity are linearly related to core clinical features of ASD. Pupil metrics were measured using a passive eye tracking task. Scores on a parent-report measure of punishment and reward sensitivity were found to be positively correlated with ASD features. Given these relationships, we assessed whether pupil measurements could be used as a neurobiological correlate of reward sensitivity and predictor of clinically significant ASD traits. In a logistic regression model, we find that the amplitude of pupil dilation, along with sex and full-scale IQ, could be used to correctly classify 84.9% of participants as having an ASD diagnosis versus not having an ASD diagnosis. This research highlights individual differences of reward sensitivity that scale with ASD features. Furthermore, reported results emphasize that functional pupil response metrics and other objective patient-level variables can be used together as predictors of ASD diagnostic status.