OBJECTIVE

This study investigated the psychometric properties of the Social Communication Questionnaire (SCQ) in a sample of children with Down syndrome (DS), many of whom had a co-occurring autism spectrum disorder (ASD). The SCQ is a widely used ASD screening measure; however, its measurement properties have not been comprehensively evaluated specifically in children with DS, a group that seems to be at higher risk for an ASD.

METHODS

Exploratory and confirmatory factor analyses, scale reliability, convergent and discriminant correlations, significance tests between groups of children with DS and DS + ASD, and diagnostic accuracy analyses were conducted.

RESULTS

Factor analyses identified 2 reliable factors that we labeled Social-Communication and Stereotyped Behavior and Unusual Interests. Pearson correlations with Autism Diagnostic Interview-Revised subscales indicated support for the SCQ's convergent validity and some support for the discriminant validity of the factor-based scales. Significance tests and receiver operating characteristic analyses indicated that children with DS + ASD obtained significantly higher SCQ factor-based and total scores than children with DS alone, and that the SCQ Total Score evidenced good sensitivity and adequate specificity.

CONCLUSIONS

Results indicated initial psychometric support for the SCQ as an ASD screening measure in children with DS. The SCQ should be considered as part of a multimethod evaluation when screening children with DS.