Differences in Adaptive Socialization Skills in ASD Vs. Non-ASD Developmental Delays in the First Two Years of Life

Background:

Research shows that delays in adaptive behavior are evident in children with ASD as young as age two, and that specific adaptive skills can differentiate toddlers with and without ASD matched on developmental level (Ventola et al., 2012). Studies also suggest that a gap between cognitive and adaptive skills increases with age (Kanne et al., 2010; Klin et al., 2007). Less information is known on profiles of adaptive functioning in children prior to age two.

Objectives:

This study investigates patterns of development of adaptive socialization skills between 12 and 24 months in toddlers with ASD and non-ASD developmental delays (DD) matched on verbal and nonverbal skills.

Methods:

Participants included toddlers at both high and low risk for ASD with age-2 preliminary diagnoses in the following categories: ASD (n=19; 74% male) and non-ASD Developmental Delays (n=20; 95% male). The Mullen Scales of Early Learning, the Vineland Adaptive Behavior Scales, Expanded Form, and the ADOS Toddler Module were administered at 12, 18, and 24 months.

Results:

No differences in Mullen scores were observed between diagnostic groups at any age. ANOVA results revealed significant differences between groups in Vineland Interpersonal age equivalent scores at 12 [F(1,36)=44.7; p<.01] and 24 [F(1,36)=170.8; p<.01] months, and Vineland Play/Leisure scores at 12 [F(1,36)=18.3; p<.05], 18 [F(1,36)=59.1; p<.01], and 24 [F(1,36)=12.1; p<.01] months, with the ASD toddlers having lower scores at all ages. Repeated Measures ANOVA results revealed that the gap between Mullen Visual Reception and Vineland Interpersonal age equivalents significantly increased from 18 to 24 months [F(1,30)=81.9; p<.001], and that this gap was larger in the ASD (10 months difference) than the DD group (7 months difference) by 24 months of age [F(1,35)=4.5; p<.05].  Pearson Correlations showed a significant negative association between Interpersonal skills and the Restricted and Repetitive Behaviors algorithm of the ADOS-T for the ASD (r = -.47; p<.05) but not DD group. Interestingly, a positive correlation was found between Play/Leisure age equivalents and the ADOS Social Affective algorithm score for the ASD (r = .53; p<.05) but not DD group, suggesting that as social affective symptoms increase, so do play and leisure scores.

Conclusions:

Results provide profiles of adaptive socialization skills in ASD in the first two years of life, with a concerning gap between early cognitive skills and adaptive interpersonal skills emerging as early as 18 months of age. By age 2, toddlers with ASD are lagging behind developmental expectations in interpersonal skills by 10 months. Distinctions between toddlers with ASD from non-ASD developmental delays are also evident in both adaptive socialization skills and diagnostic symptomatology despite no differences observed in developmental ability between the groups. These findings strengthen the utility of using the Vineland as part of the diagnostic differential in children at or under the age of two. Given the positive correlation between adaptive play skills and social/affective symptomatology, future studies investigating item-level differences in adaptive skills at these young ages is needed, as this could be a reflection of heightened solitary and leisure-time play behaviors often observed in ASD.