Cognitive functioning in children with and without Attention-deficit/Hyperactivity Disorder with and without comorbid learning disabilities.

This study attempted to determine whether children with the combined subtype of attention-deficit/hyperactivity disorder (ADHD) have impairments in cognitive functioning and motor skills. The specific effect of the comorbidity of learning disabilities (LD) was also investigated. A battery of cognitive tests was administered to 26 children with a clinical diagnosis of ADHD-combined subtype (ADHD/C), to 24 children with ADHD/C with a comorbid diagnosis of LD (ADHD/C+LD), and to 102 participants without disabilities, all between ages 7 and 10. The testing battery consisted of tasks assessing memory, visuospatial and verbal abilities, and fine motor skills. In general, the test results of children with ADHD/C were poorer than those of the control group but better than the results of children with a combined ADHD/C+LD diagnosis (with the exception of motor skills). The predictive accuracy of the testing battery tasks in children with ADHD/C and ADHD/C+LD was examined. The results of a standard procedure of discriminant function analyses revealed that the measures correctly classified 73.6% of the children.