Gesture development in toddlers with an older sibling with autism

Background: Nonverbal communication deficits are characteristic of autism spectrum disorder (ASD) and have been reported in some later-born siblings of children with ASD (heightened-risk (HR) children). However, little work has investigated gesture as a function of language ability, which varies greatly in this population. Aims: This longitudinal study characterizes gesture in HR children and examines differences related to diagnostic outcome (ASD, language delay, no diagnosis) and age. Methods & Procedures: We coded communicative gesture use for 29 HR children at ages 2 and 3 years during interactions with a caregiver at home. Outcomes & Results: Children in the ASD group produced fewer gestures than their HR peers at 2 years, though large individual differences were observed within each subgroup at both ages. In addition, reliance on particular types of gestures varied with age and outcome. Both ASD and language delay children exhibited a pattern of reduced pointing relative to their no diagnosis peers. Conclusions & Implications: Similarities and differences exist between communication in HR infants with language delay and their HR peers, reinforcing our understanding of links between verbal and nonverbal communication in populations at risk for language delay.