17917
The Integration of Vocalizations and Smiles within Joint Attention Acts in Infants at Risk for Autism Spectrum Disorder
Although it is clear that impaired levels of social-communicative behaviors are hallmark deficits of ASD, children with ASD are not devoid of such abilities. Examining the manner in which different communicative behaviors are integrated within a particular social communicative bid, in addition to their frequency of occurrence, may be necessary for detecting subtle differences in the early behavior of infants who are developing ASD relative to those who are not. To our knowledge, no study to date has examined how the integration of initiating joint attention bids (IJA) with both positive affect and vocalizations develops in infant siblings of children with ASD (high-risk infants) relative to low-risk infants.
Objectives:
The objectives of this study are to: 1) examine the morphology of joint attention bids in 12 month old infants, 2) identify differences between groups of high- and low-risk infants, and 3) examine the extent to which the integration of vocalizations and/or smiles predicts ASD symptomatology at 24 months.
Methods:
High-risk infants (n=32) and low-risk infants (n=19) were examined at 12 and 24 months as part of a larger longitudinal multisite study. At 12 months, IJA bids were coded during the Early Social Communication Scales. Vocalizations were coded if they occurred within 2 seconds of the onset or offset of an IJA bid and smiles were coded if they overlapped with the IJA bid. Four categories of IJA bids were derived: isolated bids without smiles or vocalizations; bids that integrated vocalizations only; bids that integrated smiles only; and bids that integrated bothvocalizations and smiles. Each category was represented as a percent of total IJA bids. At 24 months, the ADOS severity score (Gotham et al., 2009) was calculated for use as a continuous measure of ASD symptomatology.
Results:
Independent t-tests revealed no significant mean differences between high-risk and low-risk infants on total IJA or any of the four categories of IJA bids, ps=.54-.92. Total IJA bids did not predict ASD symptomatology at 24 months for high-risk infants or low-risk infants. However, among high-risk infants only, the percent of IJA bids that integrated both smiles and vocalizations was negatively associated with later ASD symptomatology, r(27)=-.40, p=.03, and the percent of IJA bids without vocalizations or smiles was positively associated with later ASD symptomatology, r(27)= .55, p=.01. There were no significant associations between other categories of IJA bids and later ASD symptomatology among high-risk or low-risk infants, rs=.05-.32.
Conclusions:
Characterizing the morphology of IJA bids by examining the presence of vocalizations and/or smiles may be helpful in identifying the later emergence of ASD symptomatology, even when overall levels of IJA do not. For example, failing to integrate smiles or vocalizations with IJA bids may signal less enjoyment and motivation to engage with a social partner, representing suboptimal social interactions with later implications for ASD symptomatology. Additional coding is ongoing and developmental changes between 12-18 months will be examined for each IJA category.