Objectives: To assess the ability of the Social Responsiveness Scale (SRS), Social Communication Questionnaire (SCQ) and Child Behavior Checklist (CBCL) to distinguish between ASD and NS disorders in a diverse patient sample recruited across clinical sites.
Methods: Forty-six subjects between 33 months and 17 years of age (M=83.24 months, SD=46.5) were recruited for a genetics study through three Children’s hospital departments (Outpatient Child Psychiatry=7, Developmental Services (speech, occupational therapy, developmental evaluation clinic)=10, and an autism specific clinic=18) and from community events and online resources (n=11). Diagnoses included autism=17, pervasive developmental disorder-not otherwise specified (PDD-NOS)=4, Asperger’s syndrome=2, attention deficit hyperactivity disorder=6, developmental delays=6, speech disorders=3, and other (anxiety, depression, genetic disorders)=8. Parents/legal guardians completed the CBCL, SRS, and SCQ. On the SCQ, a cut-off score of ≥12 was used for children <5 years and ≥15 for children >5 years.
Results: The mean SRS T-scores were significantly higher for the ASD (M=80, SD=12.65) than the NS group (M=68.64, SD=12.78), F(1,41)=8.58, p<.01.The mean SCQ score was also significantly higher for the ASD (M=17.62, SD=6.86) than the NS group (M=10.27, SD=6.36), F(1,41) =13.79, p<.001. However, categorical discrimination between diagnostic groups was much better for the SCQ (sensitivity=76%; specificity=77%) than the SRS.The SRS captured most children with ASD (sensitivity=90%) but misclassified most NS children when using a mild/moderate or severe categorization as the criteria for ASD (specificity=14%). When considering only the SRS severe classification as ASD, performance was similar to the SCQ (specificity=77%; sensitivity=71%).
Assessing discriminative validity of the SRS by using receiver operating curve analysis, the area under the curve was .75.Using a T-score of 73 rather than 60 resulted in a specificity of 73% and sensitivity of 76%. Age effects were found for the SCQ, and expanding the lower cut-off of >12 for children <8 years as suggested in an earlier paper (Corsello et al., 2007) improved sensitivity to 81%, but at the expense of specificity (68%). As expected, the CBCL autism scales (Withdrawn, Social Problems and PDD), were not as effective at discriminating between diagnostic groups (sensitivity=62%; specificity=41%).
Conclusions: Both the SRS and SCQ are widely used screening measures within clinical populations; however, age effects and the target populations must be considered when using them to screen for the presence of an ASD. When identifying children with ASDs in a clinical sample, using a lower cut-off for children <8 years on the SCQ and the severe classification on the SRS improved the combination of sensitivity and specificity for the measures.
See more of: Clinical Phenotype
See more of: Symptoms, Diagnosis & Phenotype