Adaptive Functioning in ASD and Ws: Shared Profiles with Unique Correlates

Background: Children with neurodevelopmental disorders, such as autism spectrum disorder (ASD) and Williams Syndrome (WS), often exhibit adaptive functioning falling behind peers with typical development (TD) and experience language delays (Hahn et al., 2014; Yang et al., 2016). However, research on the profile of relative strengths and weaknesses in the adaptive domains, both within and between groups, remains limited and inconclusive. Identifying early emerging adaptive profiles in these conditions within the first years of life is critical to inform early intervention targets, with the potential to mitigate the escalating gap in adaptive domains (Kanne et al., 2011). In particular, understanding the role of correlates, such as language, in adaptive functioning may help to elucidate shared and unique adaptive challenges across disorders.

Objectives: To examine adaptive profiles of WS, ASD, and TD to delineate syndrome-specific adaptive profiles, identify shared versus distinctive areas of strengths and needs across conditions, and examine correlates of adaptive behavior in each group, including the contribution of language.

Methods: Participants included 96 children: 52 ASD (Mage = 40.13 months), 24 WS (Mage = 52.13 months), and 20 TD (Mage = 45.25 months). Adaptive functioning was assessed using the Vineland Adaptive Behavior Scales (VABS). Developmental functioning was assessed using the Mullen Scales of Early Learning (MSEL). Developmental quotients (DQ; [mental age/chronological age]*100) were averaged for the language scales of the MSEL to create an overall verbal-DQ. Each group was divided into high versus low language groups based on mean verbal-DQ for each group.

Results: A significant group-by-domain interaction emerged (F[3,210]=10.51, p<.001) revealing differences between clinical groups. The WS group had significantly higher scores in Socialization (p= .02) but significantly lower Motor scores (p = .006) than the ASD group. Communication and Daily Living Skills (DLS) did not differ between groups. Pairwise comparisons revealed syndrome specific strengths and weaknesses: ASD Motor skills significantly higher than all domains (Communication p= .002, DLS p= .04, and Socialization p= .001); WS Socialization significantly higher than all domains (p’s< .001); no differentiated profile for TD. When variation in skills as a function of language was explored, a significant group-by-domain interaction emerged for ASD (F[3,106]=7.57, p<.001), with those in the high language group scoring significantly higher than those in the low language group (p’s< .001). For WS, a main effect of VABS domain emerged (p<.001), but there was no interaction with language. Adaptive functioning did not differ across language group or scale for TD.

Conclusions: Results of this preliminary study suggests young children with ASD and WS present with syndrome-specific adaptive profiles despite overall similar (and delayed) levels of adaptive functioning. Those with ASD outperformed those with WS on Motor functioning, were more impaired on Socialization, and did not differ on DLS or Communication. Whereas high language level within ASD predicts higher scores on all measures of adaptive functioning, differences in language do not appear to relate to adaptive functioning in children with WS or TD. Consideration of syndrome-specific and shared adaptive profiles and correlates provides relevant insight on early intervention targets and strategies.