Understanding early developmental trajectories of, and mechanisms underlying, sensory reactivity in infants at familial risk for ASD and ADHD

PROJECT SUMMARY Individuals with autism spectrum disorder (ASD) often show altered responsivity to incoming sensory stimuli (i.e., hyper-reactivity, hypo-reactivity, sensory seeking), which is associated with increased ASD symptom severity. One possible reason underlying differences in sensory processing in ASD could be attributed to attention, mainly differences in disengaging attention from task at hand and reorienting to other stimuli in one’s surroundings. However, more research is needed to thoroughly understand the link between attention and sensory behaviors in ASD. Although limited, there is some research indicating that sensory reactivity differences also occur in other neurodevelopmental disorders, including attention-deficit/hyperactivity disorder (ADHD). ASD and ADHD share some overlapping genetic factors and often co-occur. Yet little is known about the shared and distinct early symptoms, including sensory behaviors, that precede the identification of these conditions and thus may be useful in differential diagnosis. Additionally, similar to ASD, attentional differences are also reported in children with ADHD and may potentially play a role in sensory reactivity. Thus, concurrent examination of sensory behaviors, and the underlying role of attention in explaining some of these sensory differences, prior to diagnosis of ASD or ADHD is vital to understanding the way in which sensory differences contribute to symptom development. The goal of this study is to compare behavioral patterns of sensory reactivity between 12- and 24- month-olds at risk for ASD (with an older sibling with ASD, n=60), ADHD (with a sibling/parent with ADHD, n=60), and infants at low risk (no family history of ASD/ADHD, n=40), and to understand the link between attentional disengagement and sensory response patterns, including whether such links are similar or different across familial risk groups. Additionally, because altered sensory responsivity is linked with social communication and self-regulatory difficulties, we will examine concurrent and predictive associations between sensory profiles observed during early development and ASD and ADHD symptomatology. The proposed project will accomplish its objectives by utilizing a prospective longitudinal design wherein sensory reactivity and attentional measures will be administered at various time points (12 and 24 months) and symptom severity (i.e., dimensional ASD and ADHD traits) will be analyzed at 12 and 24 months in infants identified as being at high and low risk for ASD and ADHD. In order to reduce subjectivity associated with parent-report sensory questionnaires, we will use an objective lab-based observational measure (Sensory Processing Assessment), thereby increasing the rigor of our research. More thorough examination of the link between attention and sensory behaviors will be crucial as it will highlight potential mechanisms explaining some of the sensory differences that are widely observed across neurodevelopmental disorders. This may lead to better understanding of the core and associated symptoms of different neurodevelopmental disorders and provide a route for developing and refining interventions/supports.