Gesture as a predictor of language development in infants at high risk for autism spectrum disorders

In typically developing children, gesture use predates and predicts changes in language. Because language development is often delayed in later-born siblings of children with autism spectrum disorders (ASD) (who are at heightened biological risk for the disorder; heightened risk infants: HR), even those who are not eventually diagnosed with ASD, gesture may be one of the earliest indicators of later delays. To examine the pattern of gesture use and language development in HR infants, gesture referents for HR infants and low risk (LR) comparison infants were coded at 14 and 18 month home visits. HR infants who went on to receive either a language delay (LD) or ASD diagnosis exhibited less frequent gesture use and used gesture to indicate a smaller variety of referents than their typically developing peers at both 14 and 18 months. In comparison to LR infants, HR infants who went on to receive LD or ASD diagnoses also exhibited smaller increases in gesture use from 14 to 18 months. While there was a significant positive correlation between gesture frequency at 14 months and vocabulary size at 18 months for the HR group, HR infants that received eventual LD or ASD diagnoses converted a smaller proportion of gesture referents to words in later vocabulary than did LR infants. Taken together, these results suggest that early gesture use and its relationship to later language development differentiates HR infants who receive later LD or ASD diagnoses from typically developing infants, indicating that gesture may have the potential to be used as marker of language delays prior to the onset of speech