Frontal systems dysfunction in children with attention-deficit/hyperactivity disorder and learning disabilities.

Tests of attention, inhibition, working memory, motor learning, and problem solving--functions associated with the brain's frontal systems--were administered to 26 children with attention-deficit/hyperactivity disorder and learning disabilities (ADHD + LD), 22 children with LD only, and 10 with ADHD only. Percentages of abnormal test results and significantly impaired scores were higher for the two groups with LD than for the ADHD-only group. The groups differed significantly on some tests of attention-inhibition-cueing, working memory, and problem solving, with the ADHD + LD and LD groups performing worse than the ADHD-only group. Abnormalities of frontal systems tests are not exclusive ADHD characteristics and are also present in LD children, implying a strong connection between centers of "processing" and centers of "executive" functions.