• ASD
• toddler
• Vineland-II

Background. Research on adaptive behavior and autism spectrum disorder (ASD) relationship, is recently gaining more interest on how the "functioning" of ASD subjects does not only refer to quantification of intelligence or autism symptoms, but rather to how the clinical picture affect people’s ability to respond to the demands of daily life (i.e. adaptive skills).
Aims. According to this, we analyze adaptive behavior Vineland-II domains and subdomains in a large well-defined cohort of toddlers with ASD in relation to developmental skills, level of autism spectrum-related symptoms and maladaptive behaviors. Specific aims of our research are to identify “functioning groups” based on adaptive skills (Adaptive Behavior Composite score) in ASD toddlers and to compare these by age, gender, developmental skills, severity of ASD symptoms in order to delineate different clinical phenotypes. We also investigate adaptive behavior profile in “ASD severity functioning groups” based on level of autism spectrum-related symptoms in term of ADOS 2 Comparison Score (CSS- Total).
Methods. 131 toddlers with ASD (Mean age: 2,55; standard deviation: .40; 77,4% males) are assessed with Griffiths Scales-GMDS, ADOS-2, CBCL 1 ½-5 and Vineland-II. Pearson’s correlation coefficients are calculated for the entire sample for each variable. Three “functioning group” (Group 1: adequate/moderately high/high adaptive level; Group 2: moderately low adaptive level; Group 3: low adaptive level) and three different “ASD severity functioning groups” (Group A: low severity; Group B: moderate severity; Group C: high severity) are detected. Comparisons within “Functioning groups” and within “ASD severity functioning groups” are performed considering all the clinical variables.
Results. ASD toddlers show average scores into “moderately low” and “low” adaptive level range in all Vineland-II-domains, except for Motor skills, and in the Adaptive Behavior Composite scale. Five of the ten Vineland-II v-scale sample means are 2 standard deviations below the standardization sample mean. Significant positive correlations between Vineland-II scores and developmental abilities (Griffiths Scale) are found. Negative correlations emerge between Vineland-II scores and autism symptomatology, in particular in social-affect domain, and between Vineland-II and CBCL 1 ½-5 subscales. Concerning to “functioning groups”, despite the strongly significant differences on Vineland-II domains scores, found in the three “functioning group”, we have only few strong differences in the other measures and only between Group 1 and Group 3. Groups differences involve Personal-Social, Eye and Hand Co-ordination and Performance GMDS Scales and CBCL 1 ½ -5 Withdrawn, Aggressive behavior, Pervasive Developmental Problems and Oppositional Defiant Problems Scales. No ADOS-2 CSS indexes differentiate the groups. Regarding “ASD severity functioning groups”, group differences are found in all Vineland-II domains and subdomains, all GMDS scales and in the CBCL 1 ½ -5 Withdrawn and PDD Scales only between Group A versus B and a versus C.
Discussion and conclusion. To our knowledge, our study is one of the few studies to have attempted a classification of ASD in clinical phenotypes on the basis of adaptive behavior. Vineland-II is confirmed as a fundamental tool to characterize adaptive behavior in ASD toddlers according to previous literature. However, findings show that, in ASD toddlers, the use of a single assessment tool is not enough to detect well-characterized clinical ASD phenotypes. Indeed, a comprehensive assessment of ASD toddlers over time it would be necessary to better understand how each clinical feature affect others and to determine functioning profile and outcome. A longitudinal step of our research project is ongoing to give our contribution to research in this area.