Discrimination power of WISC-IV index and CHC cluster scores in the clinical diagnosis of children with specific learning disorder

In the clinical assessment of Specific Learning Disability (SLD), intellectual assessment is an important component in differential diagnosis. The Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) is one of the most used tests for this purpose. The objective of this study is to determine the predictive power of the WISC-IV scores in the clinical diagnosis of SLD. The study sample was divided into two groups, comprising Turkish children. The initial cohort comprised 97 children with SLD, while the subsequent group consisted of 85 typically developing children aged between 6 and 12 years. An independent sample t-test was used to compare the WISC-IV scores of the two groups. A one-way analysis of variance (ANOVA) was employed to compare the index scores of the WISC-IV within each group. In order to evaluate the predictive power of the WISC-IV in the context of SLD, a logistic regression analysis was conducted. The ANOVA analysis revealed significant differences in the WISC-IV index scores only among children with SLD. Furthermore, the results of logistic regression analysis indicated that all index scores could predict SLD, with the exception of perceptual reasoning. Furthermore, the Cattell-Horn-Carroll (CHC) theory of intelligence broad ability scores indicated that short-term memory (Gsm) and fluent reasoning (Gf) were the most powerful predictors of SLD. The highest index score among children with SLD was found to be perceptual reasoning, while the lowest score was for working memory. Finally, among the WISC-IV index scores, working memory was the most accurate cluster to predict SLD, while the letter-number sequence and arithmetic subtests were found to be the most precise subtest scores for the same purpose.