Coordinated communication and walking in infants at heightened risk for autism spectrum disorder

Autism spectrum disorder (ASD) is characterized by communication difficulties during infancy (Jones et al., 2014). Additionally, infants with ASD learn to walk later than neurotypical infants (West, 2018). Overwhelmingly, studies focus on either communication or motor behavior, but infant development does not behave so independently. Motor delays may have cascading adverse effects on communication. This study bridges motor and communication research, investigating how learning to walk—a major motor achievement—affects how neurotypical infants and those with ASD gesture. One hundred and sixteen infants were seen in their homes on a monthly basis from 5-18 months of age. Twenty-five infants had no family history of ASD. Ninety-one infants had an older sibling with an ASD diagnosis and were assessed by a clinician at 36 months. Based on clinical best estimates, infants were assigned to one of three outcome categories: no diagnosis, language delay, or ASD diagnosis. This study focused on data from 7 monthly sessions, which were anchored by infants’ walk onset. At each session, we coded the frequency of gestures and the extent to which they were paired with vocalizations or social gaze during 10 minutes of naturalistic play. Results revealed that infants who developed typically—regardless of genetic risk for ASD—increasingly coordinated gestures with vocalizations and gaze after they started walking. Conversely, infants later diagnosed with ASD produced fewer gestures overall and did not increase their coordinated gestures after they began walking. Findings may inform early intervention strategies for very young children with ASD. Specifically, comprehensive clinical strategies should integrate motor-based approaches (e.g., physical therapy) with communication-focused approaches (e.g., speech-language therapy) to maximize client progress.