Diagnostic Utility of Adaptive Behavior in Children with a Referral Question of ASD

Background: Impairment in adaptive functioning is a hallmark feature of Autism Spectrum Disorders (ASD). Previous research suggests that the Vineland Adaptive Behavior Scales (VABS) may have diagnostic utility when diagnosing ASD. Furthermore, the most recent version of the VABS, the Vineland-II, holds promise to obtain a more sensitive measure of developmental level in individuals with ASD in early childhood and across the lifespan. However, the diagnostic utility of the Vineland-II and the specific relationship between adaptive functioning and autistic symptomatology have not been investigated. Objectives: To examine the relationship between adaptive functioning (as measured by Vineland-II) and autistic symptomatology (as measured by Autism Diagnostic Observation Schedule (ADOS) and Autism Diagnostic Interview-Revised (ADI-R)) and to determine if the Vineland-II adds to the prediction of diagnostic outcome over and above that of the ADOS and ADI-R for individuals with a referral question of ASD. Methods: Data were pooled from the medical records of 120 children evaluated at a university-based autism clinic who received a diagnosis of Autistic Disorder (N=30), Pervasive Developmental Disorder-Not Otherwise Specified (N=30), Developmental Delay (N=30), or Language Disorder (N=30). All children were evaluated with ADI-R, ADOS, and Vineland-II measures. Pearson Product Moment Correlations will be conducted to investigate the relationships between Vineland-II Communication and Socialization scores and Communication and Social scores on the ADI-R and the ADOS. Additionally, hierarchical logistic regression analyses will examine the incremental diagnostic utility of Vineland-II above ADOS and ADI-R in predicting ASD diagnoses. Results: Data will be presented to elucidate the relationships between adaptive behavior and autistic symptomatology in children with a referral question of ASD. Additionally, data will be analyzed to determine if the Vineland-II scores improve diagnostic accuracy beyond the current gold standard of ADOS and ADI-R diagnostic evaluations. Conclusions: While the Vineland-II holds promise as a more sensitive measure of developmental level in children with ASD, it is too recent to have been widely studied and there have been no published studies in ASD using this measure to date. The present study will provide important information on how the Vineland-II scores relate to autistic symptom presentation across a variety of ASD and non-ASD developmental diagnoses. Ultimately, the identification of specific diagnostic thresholds in measures of adaptive behavior may help distinguish children with ASD from those with other developmental delays. This study takes the first step in this direction by assessing the incremental predictive utility of adaptive behavior in a comprehensive assessment of individuals with a referral question of ASD.