Quantitative and Qualitative Exploration of Meaningful Change on the Vineland Adaptive Behavior Scales (Vineland™-II) in Children and Adolescents with Autism Without Intellectual Disability Following Participation in a Clinical Trial

PURPOSE: The Vineland(TM) Adaptive Behavior Scale is often used in autism spectrum disorder (ASD) trials. The Adaptive Behavior Composite Score (VABS-ABC) is the standardized overall score (the average of the Socialization, Communication and Daily Living skills domains), and the standardized 2-Domain Composite Score (VABS-2DC) is a novel outcome measure (average of the Socialization and Communication domains). A within-person meaningful change threshold (MCT) has not been established for the VABS-2DC. This paper presents a quantitative and qualitative interpretation of what constitutes a meaningful change in these scores to individuals with ASD without Intellectual Disability (ID; IQ≥70) and their families, as reported by their study partners (SPs). PARTICIPANTS AND METHODS: Data were obtained from the aV1ation clinical trial in children and adolescents with ASD and associated exit interviews. The intent-to-treat (ITT) clinical trial population included 308 individuals with autism (85.4% male; average age: 12.4 years [standard deviation (SD)=2.97]); 124 in the child cohort (aged 5 to 12 years; average age: 9.4 years [SD=1.86]), and 184 in the adolescent cohort (aged 13 to 17 years; average age: 14.5 years [SD=1.39]). Study partners of 86 trial participants were included in the Exit Interview Population (EIP): participants represented were 83.7% male, average age: 12.3 years [SD=2.98]). Anchor and distribution-based methods were used to estimate within-person change to support a responder definition, to aid interpretation of the clinical trial data; qualitative data were used to contextualize the meaning of changes observed. RESULTS: A within-person MCT range of 4 to 8 points was proposed for both VABS-ABC and VABS-2DC, which was associated with at least a 1-point improvement on 4 different anchors. Evidence for this within-person MCT was further supported by qualitative data, which suggested any change was considered meaningful to the individual with ASD, as reported by their SP, no matter what the magnitude. CONCLUSION: A change in standardized score of 4 to 8 points constitutes a within-person MCT on both VABS-ABC and novel VABS-2DC in those with ASD and no ID. A change of this, or more, was reported by the SPs in this trial to be meaningful and highly impactful upon the individuals with ASD and their family.