Positive Affect in Infants at High Risk for ASD: A Multimethod Longitudinal Analysis
Objectives: (1) To examine positive affect and Surgency at 6 and 12 months among HR siblings who later develop ASD (HR-ASD), HR siblings without ASD (HR-nASD), and typically-developing LR children (LR-TD); 2) To examine concurrent relationships between lab-based and parent report measures of positive affectivity/Surgency at 6 and 12 months; and 3) To examine group differences on parent-reported Surgency at 18 months.
Methods: 184 infants (HR-ASD, n=21; HR-nASD, n=104; LR-TD, n=59) completed a lab-based measure of positive affectivity at 6 and 12 months and were evaluated for ASD at 24 or 36 months. Parents provided information about their infant’s Surgency by completing the Infant Behavior Questionnaire (IBQ; Gartstein, & Rothbart, 2003) at 6 and 12 months and the Early Childhood Behavior Questionnaire (ECBQ; Putnam, Gartstein, & Rothbart, 2006) at 18 months. Examiners administered a series of brief standardized probes (Social Orienting Probes; SOP) designed to elicit positive affect, including speaking in motherese, singing a nursery rhyme, tickling, playing peek-a-boo, and demonstrating a toy. Videotaped sessions were coded offline by blinded coders for the duration of the infants’ display of positive affect, standardized over the length of each probe (%PosAffect). Linear mixed models were used to examine the effects of age and diagnostic group on %PosAffect and Surgency at 6 and 12 months. ANOVA was used to examine differences between diagnostic groups on Surgency at 18 months. Pearson correlations were employed to examine concurrent relationships between %PosAffect and Surgency at 6 and 12 months.
Results: Analyses of %PosAffect (F(1, 313)=20.7, p<.001) and Surgency (F(1, 260)=19.6, p<.001) both revealed only a main effect of age (6<12months). Diagnostic groups differed significantly on Surgency at 18 months, F(2, 124)=4.8, p=.009; LR-TD>HR-ASD). Positive affect displayed during the SOP at 12 months was significantly correlated with concurrent Surgency, r=.20, p=.02, with a trend toward a significant correlation between measures at 6 months, r=.16, p=.09.
Conclusions: Results indicate that neither positive affect during a live social interaction nor Surgency as reported by parents differed across the three groups at 6 or 12 months, but at 18 months of age, HR-ASD infants displayed lower Surgency than LR-TD infants. Results are largely consistent with the previous literature. We extend this work by showing congruency between parent report of Surgency and an observational measure of positive affectivity. Future research should examine additional aspects of temperament using a multimethod approach.