This study investigated whether treatment naïve adults with Attention Deficit Hyperactivity Disorder (ADHD; n = 33; 19 female) differed from healthy controls (n = 31; 17 female) in behavioral performance, event-related potential (ERP) indices of preparatory attention (CueP3 and late CNV), and reactive response control (Go P3, NoGo N2, and NoGo P3) derived from a visual cued Go/NoGo task. On several critical measures, Cue P3, late CNV, and NoGo N2, there were no significant differences between the groups. This indicated normal preparatory processes and conflict monitoring in ADHD patients. However, the patients had attenuated Go P3 and NoGoP3 amplitudes relative to controls, suggesting reduced allocation of attentional resources to processes involved in response control. The patients also had a higher rate of Go signal omission errors, but no other performance decrements compared with controls. Reduced Go P3 and NoGo P3 amplitudes were associated with poorer task performance, particularly in the ADHD group. Notably, the ERPs were not associated with self-reported mood or anxiety. The results provide electrophysiological evidence for reduced effortful engagement of attentional resources to both Go and NoGo signals when reactive response control is needed. The absence of group differences in ERP components indexing proactive control points to impairments in specific aspects of cognitive processes in an untreated adult ADHD cohort. The associations between ERPs and task performance provided additional support for the altered electrophysiological responses.

Lesion studies have indicated that at least the three executive processes can be differentiated in the frontal lobe: Energization, monitoring and task setting. Event related potentials (ERPs) in Go/NoGo tasks have been widely used in studying executive processes. In this study, ERPs were obtained from EEG recorded during performance of a cued Go/NoGo task. The Contingent Negative Variation (CNV) and P3NoGo waves were decomposed into four independent components (ICs), by applying Independent Component Analysis (ICA) to a collection of ERPs from 193 healthy individuals. The components were named IC CNVearly, IC CNVlate, IC P3NoGoearly and IC P3NoGolate according to the conditions and time interval in which they occurred. A sub-group of 28 individuals was also assessed with neuropsychological tests. The test parameters were selected on the basis of studies demonstrating their sensitivity to executive processes as defined in the ROtman-Baycrest Battery for Investigating Attention (ROBBIA) model. The test scores were categorized into the domain scores of energization, monitoring and task setting and correlated with the amplitudes of the individual ICs from the sub-group of 28 individuals. The energization domain correlated with the IC CNVlate and IC P3NoGoearly. The monitoring domain correlated with the IC P3NoGolate, while the task setting domain correlated with the IC CNVlate. The IC CNVearly was not correlated with any of the neuropsychological domain scores. The correlations between the domains and ICs remained largely unchanged when controlling for full-scale IQ. This is the first study to demonstrate that executive processes, as indexed by neuropsychological test parameters, are associated with particular event-related potentials in a cued Go/NoGo paradigm.

The present study investigated how components of ERPs are modulated when participants optimize speed versus accuracy in a cued go/no-go task. Using a crossover design, 35 participants received instructions to complete the task prioritizing response speed in half of the task, and accurate responding in the other half of the task. Analysis was performed on the contingent negative variation (CNV), P3go, and P3no-go and the corresponding independent components (IC), as identified by group independent component analysis. After speed instructions, the IC CNV(late), P3go(anterior), P3no-go(early), and P3no-go(late) all had larger amplitudes than after accuracy instructions. Furthermore, both the IC P3go(posterior) and IC P3go(anterior) had shorter latencies after speed than after accuracy instructions. The results demonstrate that components derived from the CNV and P3 components are facilitated when participants optimize response speed. These findings indicate that these ERP components reflect executive processes enabling adjustment of behavior to changing demands.

Changes in P3no-go may be a clinically useful marker of response to stimulants.