Re‐adjusting the cut‐off score of the K K orean version of the C C hildhood A A utism R R ating S S cale for high‐functioning individuals with autism spectrum disorder

摘要

Aim The current cutoff score of the Korean version of the Childhood Autism Rating Scale (KCARS) does not seem to be sensitive enough to precisely diagnose highfunctioning autism. The aim of this study was to identify the optimal cutoff score of KCARS for diagnosing highfunctioning individuals with autism spectrum disorders (ASD). Methods A total of 329 participants were assessed by the Korean versions of the Autism Diagnostic Interview Revised (KADIR), Autism Diagnostic Observation Schedule (KADOS), and KCARS. IQ and Social Maturity Scale scores were also obtained. Results The true positive and false negative rates of KCARS were 77.2% and 22.8%, respectively. Verbal IQ (VIQ) and Social Quotient (SQ) were significant predictors of misclassification. The false negative rate increased to 36.0% from 19.8% when VIQ was 69.5, and the rate increased to 44.1% for participants with VIQ 69.5 and SQ 75.5. In addition, if SQ was 83.5, the false negative rate increased to 46.7%, even if the participants VIQ was d69.5. Optimal cutoff scores were 28.5 (for VIQ d 69.5 and SQ d 75.5), 24.25 (for VIQ 69.5 and SQ 75.5), and 24.5 (for SQ 83.5), respectively. Conclusion The likelihood of a false negative error increases when KCARS is used to diagnose highfunctioning autism and Asperger's syndrome. For subjects with ASD and substantial verbal ability, the cutoff score for KCARS should be readjusted and/or supplementary diagnostic tools might be needed to enhance diagnostic accuracy for ASD.