Comparison of Sustained Attention and Response Inhibition between Adults with Attention Deficit/Hyperactivity Disorder and Normal Controls during Cognitive Load Changes of Continuous Performance Task

Deficits in inhibitory control and attention maintenance as the main components of executive functions are of the key symptoms of attention deficit/hyperactivity disorder (ADHD). This study aimed to investigate these variables in adults with ADHD compared to Normal individuals.
This research conducted with causal-comparative design. The population consists of 400 adult volunteers who completed Conner’s Adult ADHD rating scale (CAARS). Based on its results, 50 individuals were invited to perform Continuous Performance Task (CPT) in two groups of adults with ADHD symptoms and normal participants. Ten persons received formal diagnosis of ADHD by a psychiatrist’s interview according to DSM-IV criteria and ten persons were randomly selected as controls. Two groups were compared in terms of mean reaction time, omission error, commission error and standard error of reaction time in different inter-stimulus intervals. The collected data were analyzed using repeated measures analysis of variance and post-hoc Bonferroni test.
Findings indicated there are significant differences between two groups in terms of omission error (p-value = 0.011), commission error (p-value = 0.047) and standard error of reaction time (p-value Adults with ADHD had lower performance in attentional maintenance and inhibition control compared to normal individuals especially in effortful attentional condition of CPT.