Abstract
Purpose Infants with autism spectrum disorder (ASD) produce fewer play actions and gestures than neurotypical infants (e.g., Mastrogiuseppe et al., 2015; Veness et al., 2012; Zwaigenbaum et al., 2005). The purpose of this study was to investigate whether different "types" of actions and gestures are more or less likely to develop atypically in ASD. Method We examined eight types of actions and gestures longitudinally from ages 8 to 14 months in 80 infants with a heightened risk for developing ASD by virtue of having an affected older sibling (high risk [HR]; e.g., Ozonoff et al., 2011) and 25 infants with no such familial risk (low risk). Data were collected using the MacArthur-Bates Communicative Development Inventories (Fenson et al., 1994, 1993). Results HR infants later diagnosed with ASD showed less growth across nearly all types of actions and gestures compared to the low-risk comparison group. Importantly, these HR infants who were later diagnosed with ASD also exhibited reduced growth in frequent deictic gestures and in actions that involve object manipulation relative to HR infants with non-ASD language delay. Conclusions During infancy, it is challenging for clinicians to distinguish ASD from other early communicative delays (e.g., Camarata, 2014). Our results indicate that deictic gestures, as well as actions and gestures involving object manipulation, may be useful targets of surveillance strategies for HR infants and could support early detection efforts for ASD.