Validity Testing of a Social Communication Classification System of Functioning for Preschool Children with Autism Spectrum Disorder (ASD)

Friday, May 13, 2016: 5:30 PM-7:00 PM
Hall A (Baltimore Convention Center)
B. M. Di Rezze1,2, P. Stratford1, P. Rosenbaum2, L. Zwaigenbaum3, M. J. C. Hidecker4, H. Viveiros2 and M. Law1, (1)School of Rehabilitation Science, McMaster University, Hamilton, ON, Canada, (2)CanChild Centre for Childhood Disability Research, McMaster University, Hamilton, ON, Canada, (3)University of Alberta, Edmonton, AB, Canada, (4)Communication Disorders, University of Wyoming, Laramie, WY
Background: We have created an ASD functional classification system based on the WHO’s International Classification of Functioning, Health and Disability (ICF). The Autism Classification System of Functioning: Social Communication (ACSF:SC) is a novel 5-level descriptive system with demonstrated consistency in ratings of both capacity (i.e., best) and typical performance by parents and professionals of preschool children with ASD.

Objectives: To examine the construct validity of the ACSF:SC across settings (i.e., home and clinic) and the spectrum of abilities of preschool children with ASD.

Methods: Support for ACSF:SC construct validation was proposed with a priori hypotheses by the research team based on Pearson correlation coefficients between ACSF:SC ratings (parents or professionals) and sub-domains of other measures. Construct validity was examined using concurrent ratings of the ACSF:SC with prominent ASD measures that evaluate function and/or social communication to assess: (1) convergent validity: how well the ACSF:SC correlates with measures possessing domains related to social communication; and (2) discriminant validity: weak correlations with unrelated functional domains. Professionals and parents completed the ACSF:SC ratings, and a concurrent self-report measure (Social Responsiveness Scale 2nd edition [SRS-2]). Parents also completed two interview-based measures: the Vineland Adaptive Behavior Scale-2 (VABS-2) and the Autism Diagnostic Interview-Revised (ADI-R) algorithm. For the ADI-R algorithm, only Social Interactions (section A) and Communication (section B) were completed.  

Results: The sample included 36 children whose ACSF:SC and SRS-2 were completed by their parents. The mean age (SD) was 4.3 (0.9) years (85% male). 27 (75%) parents completed an interview to collect data for the VABS-2 and ADI-R algorithm. 33 professionals completed ACSF:SC and SRS-2 ratings. Descriptive data showed that children categorized as either verbal or non-verbal based on the ADI-R algorithm had an ACSF:SC across most of the 5 ability levels (Table 1). Mean composite scores for parent scores on the SRS-2 and VABS2 were generally increasing across improved functioning on the 5 ACSF:SC levels (i.e., ACSF:SC rating of 1 = highest ability) (Table 2). Convergent validity testing between the SRS-2 subdomain (Social Communication and Interaction [SCI]) and ACSF:SC showed statistically significant correlations for capacity (95% confidence interval[CI]), for parents: 0.52 (0.23,0.73) and for professionals: 0.63 (0.36,0.80), respectively. Discriminant validity comparing the ACFS:SC tool with an unrelated sub-domain of function on the VABS-2 (i.e., Motor Skills) demonstrated no significant correlations for capacity, -0.34 (-.64,0.04).

Conclusions: Without a gold standard, testing validity of a novel tool is challenging, requiring other measures that may be only partly related to its core construct (i.e., social communication functioning). These data demonstrated that ACSF:SC ratings by both parents and professionals were related to SRS-2-defined social communication. Parent ratings of children identified as having both verbal and non-verbal abilities also demonstrated abilities across most of the five ACSF:SC levels, indicating that social communication ability is not contingent on verbal ability. These data are promising starting point for an ongoing validation process of the ACSF:SC.