Exploratory behavior and developmental skill acquisition in infants with Down syndrome

Infants learn about objects by exploring them. Typically developing infants actively explore objects through visual, manual, and oral modalities. Attenuated exploratory behavior has been observed in various neurodevelopmental disorders, including Down syndrome (DS), presumably limiting learning options. However, a direct link between exploration and overall developmental functioning has not been characterized. This study used a Latent Profile Analysis framework to examine within-syndrome variability in exploratory behavior in infants with DS and the developmental correlates of different exploratory behavior profiles. Participants were 45 infants with DS (CA = 9.58 months; SD = 3.62) who completed an object exploration activity and the Bayley Scales of Infant Development-III (BSID-III; Bayley, 2006). Exploration behavior was coded for the percentage of time engaged in visual, manual, and oral exploration. Results indicated that a 2-profile solution provided the best model fit for exploratory behavior, yielding profiles that represented either an Active (57.78% of the sample) or a Passive Exploratory (42.22% of the sample) profile. The Active Exploratory profile was associated with significantly higher age equivalent scores on the BSID-III Cognitive, Communication, and Motor domains than the Passive Exploratory profile. Other factors, such as sex and biomedical risk factors, were not associated with exploratory profiles. These findings offer a more nuanced understanding of early within-syndrome heterogeneity in DS, and demonstrate that impoverished early exploratory behavior may serve as an important indicator of increased risk for more pronounced developmental delays in DS.