Early Object Exploration and Later Social Concerns within the Context of Elevated ASD Risk
With the current prevalence of an autism spectrum disorder (ASD) diagnosis at 1 in 59 (CDC, 2018), early developmental monitoring studies are committed to identifying early behavioral risk markers that may inform later developmental concerns. Previous research highlights atypical play behaviors during object exploration as potential risk markers for ASD (e.g., unusual sensory interests, repetitive movements; Wetherby et al., 2004). Within prospective infant sibling designs, previous research has documented atypical object exploration as early as 18 months in children who subsequently received an ASD diagnosis (e.g., spinning, prolonged rotation, unusual visual interests; Ozonoff et al., 2008). However, it is unclear if object exploration atypicality is a unique risk marker for ASD or if it is also present in children with other developmental concerns or those with sub-clinical social difficulties.
The present study expands our understanding of atypical object exploration as an early risk marker of ASD by assessing whether (1) high-risk infant siblings with developmental concerns, as indexed by standardized developmental assessments, also exhibit atypical play behaviors, compared to their typically developing peers, and (2) if atypical object exploration informs continuous measures of social difficulty, as indexed by a parent-report measure.
As part of a prospective longitudinal study, 63 infants/toddlers (high-risk group n= 31; low-risk group n= 32) completed an object exploration task at 12, 15, and/or 18 months of age. The task included five objects: rattle, ring, metal lid, sticks, and cars. Each object was presented to the infant/toddler for 30 seconds and in the final 30 seconds of the task all objects were presented together. Play behaviors were recorded and coded for evidence of object spinning, mouthing, and rotating—following an existing coding scheme (Ozonoff et al., 2008). Mothers completed the Vineland Adaptive Behavior Scales (VABS) when infants were 24 months to index adaptive functioning in the socialization domain. Between 24 and 36 months, children completed an outcome visit and, following previously established criteria, children were assigned to either developmental concerns (n= 20) or typically developing (n= 43) groups.
Regression analyses were conducted with terms for infant sex and maternal education. Overall, there were significant group differences for select atypical play behaviors. Specific to Aim 1, infants/toddlers with developmental concerns demonstrated more object spinning than their typically developing peers. However, infant/toddler object mouthing and rotating were comparable across groups (Table 1). Specific to Aim 2, continuous VABS scores were not associated with the assessed behaviors (Table 2).
Infant object exploration in the first two years of life may inform later developmental risk. Although this sample was small, object spinning still differentiated children with developmental concerns from those with typical development. Intriguingly, infant play behaviors did not predict social competence more globally. Therefore, the prospective risk associated with object exploration may not be specific to social skills but rather may capture other elements of ASD (e.g., repetitive behaviors and interests). This study adds to a growing body of work documenting how early object exploration may inform ASD and other developmental risks.