Parent responses to infant vocalization across the transition from crawling to walking in typical and atypical development

• In Event: 1-093 - Understanding Motor Activity in Infants: The Role of Parent-Child Interaction

Integrative Statement

When neurotypical infants learn to walk, they display more “moving” communicative bids—they walk before they vocalize or gesture (Karasik, Tamis-LeMonda & Adolph, 2014; Clearfield, 2011). In turn, parents respond more frequently to moving bids than to stationary bids (Karasik, Tamis-LeMonda & Adolph 2014). Moving bids may be more salient, as locomoting to a parent reflects a high degree of directedness on the part of the infant.
Does this phenomenon differ in autism spectrum disorder (ASD), which is characterized by communication deficits and atypical motor development (e.g., Jones et al., 2014; West, 2018)? The present study measured: (1) trajectories of infants’ moving and stationary vocalization production, and (2) trajectories of parents’ verbal responses to vocalizations; across the transition to walking in infants who have a heightened risk (HR) of developing ASD by virtue of having an older diagnosed sibling (recurrence rate is 18.7%, Ozonoff et al., 2011).
Forty-eight HR infants were visited at home monthly as part of a larger study. This study focused on 7 visits, which began 4 months before walk onset, and concluded 3 months after walk onset. Walk onset was established through parent-report. At each visit, a 10-minute naturalistic observation was coded for infants’ vocalization production, and parent responses to these vocalizations. Coders identified whether each vocalization was “moving”—if it overlapped or occurred 2 seconds after infant locomotion—or “stationary” if it did not. At 36 months, 8 infants received an ASD diagnosis, 11 had language delay but not ASD, and 29 received no diagnosis and developed typically.
Hierarchical Linear Models assessed linear growth across the transition from crawling to walking in infants’ moving and stationary vocalizations, and in the proportion of moving/stationary vocalizations that elicited a verbal response from parents. Additionally, models tested whether intercepts and slopes differed for ASD and language delayed infants compared to typically developing infants. Age of walk onset was covaried.
Infants in all outcome groups increased their rate of moving vocalizations, p < .001 (Fig 1A). The proportion of moving vocalizations that elicited a response did not significantly change over time—that is, parents were equally responsive to crawling and walking moving bids—and there were no significant differences across outcome groups (Fig 1C.). A different pattern emerged among stationary vocalizations for infants with ASD. Throughout the period, ASD infants produced fewer stationary vocalizations than their typically developing peers, p = 0.014 (Fig 1B). Moreover, parents of infants with ASD responded less often to stationary vocalizations than did parents of infants with no diagnosis, p = 0.006 (Fig 1D).
Infant locomotion plays an important role in eliciting timely, verbal responses from caregivers, and particularly so for infants who develop ASD. Stationary vocalizations are less frequent overall, and less effective in eliciting responses, for infants with ASD relative to neurotypical infants. However, the coordination of locomotion and vocalization appears to enhance the saliency of social bids in ASD, and thus elicits rich, contingent verbal input.

Authors

• Kelsey West, University of Pittsburgh
  Presenting Author

• Jana M Iverson, University of Pittsburgh
  Non-Presenting Author