“Optimal early social environment” as a protective factor for at-risk infants? A closer study of parent-infant interactions

Background: We recently reported from the British Autism Study of Infant Siblings (BASIS) that 6- and 12-month parent-infant interactions in at-risk siblings differ from those with low-risk, and that – among at-risk siblings – particular global aspects of interaction at 12 months predicted 3-year classification of autism spectrum disorder (ASD) (Wan et al., 2013). This supports recent models of the early emergence of ASD in which infant intrinsic risk susceptibilities in behaviour may be amplified by interaction within the early social environment into an increasingly atypical developmental trajectory. Conversely, it follows that optimising the early social environment of infants at risk of ASD may serve as a protective or ‘resiliency’ factor. 

Objectives: To examine in a series of exploratory analyses whether those at-risk infants (of siblings with ASD) with early behavioural atypicalities but more optimal parent-infant interactions at 12 months were less likely to receive an ASD diagnosis outcome at 3 years than those with lower quality interactions. 

Methods: Six-min videotaped episodes of parent-infant unstructured play of infants at 6-10 months and 12-15 months in at-risk and low-risk infants in a laboratory setting were rated blind on the Manchester Assessment of Caregiver-Infant Interaction (MACI). The Autism Observation Scale for Infants(AOSI) was administered for concurrent behavioural signs of ASD features. Systematic consensus diagnostic classification of ASD was made at 3 years for the at-risk siblings.

Results: Within our cohort of infants at familial risk of ASD (N = 43), we identified a sub-group with elevated behavioural atypicalties at 12 months (AOSI total score >3; n = 20). In this high-atypicality group, 50% whose parent-infant interactions were rated as low in mutuality received an ASD classification at 3 years compared with 17% of those with mutual interactions (and none of the low-atypicality high-mutuality group received an ASD diagnosis). Although we had previously reported group differences by at-risk status (at-risk ASD, at-risk no-ASD, low risk) in parent interactive behaviours at 6 and 12 months, among the high-atypicality group, it was MACI infant affect that most differentiated those who went onto receive a diagnosis (67% with more positive affect compared with 18% with more negative affect). However, this may reflect infant positivity within the parent-infant interactive context rather than infant social skill, since 60% of infants who showed a social smile (response to examiner) in the AOSI were rated as showing positive affect in parent-infant interaction, and AOSI social smile alone did not predict later diagnosis. Exploratory analyses of other areas of parent-infant interaction will also be presented.

Conclusions: The possibilities for building resilience in this at-risk group (or not) will be discussed based on these sub-group analyses and our previous findings from the complete sample. There are insights and limitations in studying whether the early interactive context may serve as a protective factor for infants at very high risk (familial risk and behaviourally) of ASD. Finally, we will consider the implications for early social interventions which focus on optimising parent-infant interaction in infants with an older sibling with ASD.