Activating tasks for the study of visual-spatial attention in ADHD children: a cognitive anatomic approach.

The clinical label attention deficit hyperactivity disorder (ADHD) suggests that this syndrome is a disorder of attention. However, the presumed attentional deficits have not been linked either to specific cognitive operations or to specific neural systems. To provide this link, theories of the cognitive anatomy of attention were used to generate hypotheses about specific visual-spatial attentional deficits in children with ADHD. A cued reaction-time test was used to assess covert and overt shifts of attention theoretically linked to two neuroanatomically defined attentional systems in the posterior and anterior parts of the human brain. The early, posterior-based covert shift of attention was found to be normal in ADHD children, but a later, anterior-based overt shift of attention was abnormal as reflected by a significant lateral difference in reaction time. This was interpreted as a failure to sustain focused attention.