Sensitivity and specificity of the Modified Checklist for Autism in Toddlers and the Social Communication Questionnaire in preschoolers suspected of having pervasive developmental disorders.

This study assessed the psychometric properties of the Modified Checklist for Autism in Toddlers (M-CHAT) and the Social Communication Questionnaire (SCQ) in a sample of preschool children referred for possible pervasive developmental disorders (PDDs). The sample consisted of 82 children between the ages of 18 and 70 months (54 with a PDD diagnosis and 28 with non-PDD diagnoses). M-CHAT scores were analyzed for 56 children aged 18-48 months old and SCQ scores were analyzed for 65 children aged 30-70 months old. Optimal sensitivity and specificity were achieved using the cutoff score of any three items on the M-CHAT and lowering the cutoff score of the SCQ. The diagnostic agreement of both instruments was also compared in an overlapping subsample of 39 children aged 30-48 months. Overall, the M-CHAT and SCQ appear to more accurately classify children with PDDs who have lower intellectual and adaptive functioning.