Impaired conflict resolution and alerting in children with ADHD: evidence from the Attention Network Task (ANT)

Background: An important theory of attention suggests that there are three separate networks that execute discrete cognitive functions. The ‘alerting’ network acquires and maintains an alert state, the ‘orienting’ network selects information from sensory input and the ‘conflict’ network resolves conflict that arises between potential responses. This theory holds promise for dissociating discrete patterns of cognitive impairment in disorders where attentional deficits may often be subtle, such as in attention deficit hyperactivity disorder (ADHD). Methods: The Attentional Network Test (ANT), a behavioural assay of the functional integrity of attention networks, was used to examine the performance of 73 children with ADHD and 73 controls. Results: Performance on the ANT clearly differentiated the children with and without ADHD in terms of mean and standard deviation (SD) of reaction time (RT), the number of incorrect responses made and the number of omission errors made. The ADHD group demonstrated deficits in the conflict network in terms of slower RT and a higher number of incorrect responses. The ADHD group showed deficits in the alerting network in terms of the number of omission errors made. There was no demonstration of a deficit in the orienting network in ADHD on this task. Conclusions: The children with ADHD demonstrated deficits in the alerting and conflict attention networks but normal functioning of the orienting network.