Is the Vineland-3 Comprehensive Interview Form a Multidimensional or Unidimensional Scale? Structural Analysis of Subdomain Scores Across Early Childhood to Adulthood

Factor structure of the VABS-3 Comprehensive Parent/Caregiver form in autistic individuals: Poor fit of three-factor and unidimensional models

LAY ABSTRACT

Adaptive behavior is a broad set of skills needed to function in everyday life. The Vineland Adaptive Behavior Scales (VABS-3) is commonly used to measure adaptive behavior. It divides adaptive behavior into three domains, Communication, Daily Living Skills, and Socialization, each of which are split into subdomains. Analyses of this three-part structure of the first version of VABS used the instrument as an interview, but now it is done as a questionnaire as well. The structure has not been well supported in samples of autistic people, who often have different strengths and challenges in adaptive behavior compared with non-autistic people. Because adaptive behavior is an important concept in autism research and online-administered questionnaires are increasingly common, it is important to ensure the structure of the VABS-3 Comprehensive Parent/Caregiver Form (VABS-3:CPCF; a questionnaire) works well for autistic individuals across a range of abilities. This study aimed to investigate whether VABS-3:CPCF measures adaptive behavior similarly in verbal and minimally verbal autistic people. However, the data didn't fit the structure in the first step of the analysis, so this could not be investigated. The next analyses also found the three-domain structure didn't fit in different age and language groups. In addition, the data didn't fit a structure combining all the domains into 1 (unidimensional). These results suggest that neither the three-factor or unidimensional structure fit the VABS-3:CPCF, cautioning against interpretation of domain or overall adaptive behavior composite scores in autistic individuals and further encouraging careful consideration of administration format.

Disentangling global and domain-level adaptive behavior trajectories among children with autism spectrum disorder

BACKGROUND

Heterogeneity in adaptive behavior abilities among people with autism spectrum disorder (ASD) is expressed not only as uneven levels of impairment across domains, but also in the developmental trajectories of adaptive skills. We studied the question of whether, after accounting for global adaptive behavior development, we find evidence of heterogeneity in the trajectories of specific domains of adaptive behavior.

METHODS

A sample of 504 children with ASD was obtained by combining data from two independent natural history studies conducted in North America. We used a factor of curves model to explain growth between 36 and 138 months in Vineland Adaptive Behavior Scales, Second Edition (VABS) age equivalents as a function of domain-specific and global growth processes.

RESULTS

The domain-specific trajectories in all three domains (Communication, Daily Living Skills, and Socialization) reflected impairment relative to age expectations as well as slower-than-expected growth with age, and the parameters of these trajectories were moderately-to-strongly correlated across domains. The global adaptive behavior trajectory had an initial (36-41 months of age) developmental level of about 22 age-equivalent months, and eventually slowed after initially increasing by about 6 months each year. The global trajectory accounted for the majority of variance in the domain-level processes; however, additional variance remained (14%-38%) in the domain-level intercepts, slopes, and quadratic processes.

CONCLUSIONS

These results extend existing theoretical and empirical support for the hierarchical structure of adaptive behavior to include its development over time in clinical samples of children with ASD. A latent global trajectory may be sufficient to describe the growth of adaptive behavior in children with ASD; however, the remaining domain-specific variability after accounting for global adaptive behavior development allows for the possibility that differential effects of intervention on specific domains may be possible and detectable.

Italian Diagnostic Adaptive Behavior Scale: Reliability and diagnostic accuracy compared with the Vineland-II

BACKGROUND

The Diagnostic Adaptive Behavior Scale (DABS) is a short scale with excellent properties to assess the conceptual, social, and practical adaptive behavior domains for the diagnosis of intellectual disability (ID) in individuals aged 4-21 years.

AIMS

Investigate the test-retest and inter-respondent reliability of the Italian adaptation of the DABS, verify its diagnostic accuracy in identifying individuals with ID and excluding individuals with typical development (TD), and compare its psychometric properties to those of the Vineland-II.

METHODS

Test-retest reliability: The same respondent completed the Italian DABS for the same assessed person at two separate times (n = 71). Inter-respondent reliability: Two respondents for the same assessed person completed the Italian DABS independently (n = 57). Diagnostic accuracy: The same respondent completed the Italian DABS and Vineland-II for the same assessed person (n = 378; 50 % ID, 50 % TD).

RESULTS

Italian DABS test-retest and inter-respondent correlation coefficients were excellent. Italian DABS sensitivity was 86 % and specificity was 99 %, Italian DABS Areas Under the ROC Curves were excellent (or good, practical skill domain), and comparable to the results reported for the Vineland-II.

CONCLUSIONS

The Italian DABS is an excellent measure to evaluate the adaptive behavior for ID diagnosis; it is comparable to the Vineland-II but being shorter, the Italian DABS requires less time to administer.