Intellectual characteristics of children with attention deficit hyperactivity disorder and developmental dyslexia

Abstract

OBJECTIVE To study the intellectual characteristics of children with attention deficit hyperactivity disorder (ADHD) and developmental dyslexia (DD). METHODS A total of 55 children with ADHD and DD (ADHD+DD group), 150 children with ADHD alone (ADHD group), and 22 children with DD alone (DD group) were enrolled as subjects. Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) was used to evaluate and compare intellectual characteristics among the three groups. RESULTS There were significant differences in the scores of full-scale intelligence quotient (FSIQ), verbal comprehension index, perceptual reasoning index, and working memory index among the three groups (P < 0.05):the ADHD+DD group had significantly lower scores of FSIQ, verbal comprehension index, perceptual reasoning index, and working memory index than the ADHD group, as well as a significantly lower FSIQ score than the DD group. A comparison of the 10 core subtests in WISC-IV showed that compared with the ADHD group, the ADHD+DD group had significantly lower scores of similarities, vocabulary, comprehension, recitation, picture concepts, matrix reasoning, and letter-number sequencing (P < 0.05). Compared with the DD group, the ADHD+DD group had significantly lower scores of vocabulary, similarities, picture concepts, matrix reasoning, and recitation (P < 0.05). CONCLUSIONS Compared with the children with ADHD alone, the children with ADHD and DD have more severe impairment of FSIQ, verbal comprehension, perceptual reasoning, and working memory, and therefore, it is suggested to enhance the training on similarities, vocabulary, matrix reasoning, picture concepts, and recitation for children with ADHD and DD in clinical practice.