Methylphenidate restores link between stop-signal sensory impact and successful stopping in adults with attention-deficit/hyperactivity disorder.

Background: The ability to revise one's action plans, as reflected in so-called stopping performance, is of fundamental importance to adaptive behavior. Previous studies in children and adults with attention-deficit/hyperactivity disorder (ADHD) have revealed impaired stopping, which improved after the administration of methylphenidate (MPH). Event-related brain potentials revealed that one crucial mechanism in adequate stopping is the link between the cortical areas that process the signal to stop and the motor system (stop N1).

Disentangling deficits in adults with attention-deficit/hyperactivity disorder.

Context: A lack of inhibitory control has been suggested to be the core deficit in attention-deficit/hyperactivity disorder (ADHD), especially in adults. This means that a primary deficit in inhibition mediates a cascade of secondary deficits in other executive functions, such as attention. Impaired stopping has been claimed to support the inhibition hypothesis.

Inhibition in children with attention-deficit/hyperactivity disorder: a psychophysiological study of the stop task.

Background: The purpose of the study was to investigate and identify abnormal brain activity, as revealed by event-related potentials (ERPs) concurring with deficient inhibitory control in children with attention-deficit/hyperactivity disorder (ADHD).

Methods: Performance and ERPs from 16 children with ADHD and 16 control subjects were compared in the stop-signal paradigm.

Results: The ADHD children showed a lower inhibition percentage and their (estimated) response time to the stop signal was disproportionally longer compared to the slowing of reaction times to primary-task stimuli.