Predicting children with pervasive developmental disorders using the Wechsler Intelligence Scale for Children-Third Edition.

An original combination score (i.e. the sum of Vocabulary and Comprehension subtracted from the sum of Block Design and Digit Span) was created from the four Wechsler Intelligence Scale for Children-Third Edition (WISC-III) subtests identified by discriminant analysis on WISC-III data from 139/129 children with/without pervasive developmental disorders (PDD; mean, 8.3/8.1 years) and its utility examined for predicting PDD. Its best cut-off was 2/3, with sensitivity, specificity, positive and negative predictive values of 0.68, 0.61, 0.65 and 0.64, respectively. The score seems useful, so long as clinicians are aware of its limitations and use it only as a supplemental measure in PDD diagnosis.