Event-Related-Potential (ERP) Correlates of Performance Monitoring in Adults With Attention-Deficit Hyperactivity Disorder (ADHD)

Abstract

Introduction: Attention-deficit hyperactivity disorder (ADHD) is one of the most frequent neurodevelopmental disorders in children and tends to persist into adulthood. Evidence from neuropsychological, neuroimaging, and electrophysiological studies indicates that alterations of error processing are core symptoms in children and adolescents with ADHD. To test whether adults with ADHD show persisting deficits and compensatory processes, we investigated performance monitoring during stimulus-evaluation and response-selection, with a focus on errors, as well as within-group correlations with symptom scores. Methods: Fifty-five participants (27 ADHD and 28 controls) aged 19-55 years performed a modified flanker task during EEG recording with 64 electrodes, and the ADHD and control groups were compared on measures of behavioral task performance, event-related potentials of performance monitoring (N2, P3), and error processing (ERN, Pe). Adult ADHD Self-Report Scale (ASRS) was used to assess ADHD symptom load. Results: Adults with ADHD showed higher error rates in incompatible trials, and these error rates correlated positively with the ASRS scores. Also, we observed lower P3 amplitudes in incompatible trials, which were inversely correlated with symptom load in the ADHD group. Adults with ADHD also displayed reduced error-related ERN and Pe amplitudes. There were no significant differences in reaction time (RT) and RT variability between the two groups. Conclusion: Our findings show deviations of electrophysiological measures, suggesting reduced effortful engagement of attentional and error-monitoring processes in adults with ADHD. Associations between ADHD symptom scores, event-related potential amplitudes, and poorer task performance in the ADHD group further support this notion.

Keywords: ADHD; ERN; P3; Pe; event-related potentials; performance monitoring.

FIGURE 1

ERN and Pe topographic plots. Topographic plots of the amplitude difference between correct and incorrect outcomes at 46 (ERN) and 212 ms (Pe) post-response. Scaling from –5 to 5 μV. Voltage maximum is at fronto-central midline sites that were used for further component analysis as a region of interest average. ERN, error-related negativity; Pe, error positivity.

FIGURE 2

Stimulus-locked and response-locked event-related potentials (ERPs). Stimulus-locked Grand average ERP at a central region of interest for compatible (green), incompatible (blue), and error (red) trials in (A) control participants and (B) ADHD participants. Response-locked Grand average ERP for compatible (green), incompatible (blue), and error (red) trials in (C) control participants and (D) ADHD participants. ADHD, attention-deficit/hyperactivity disorder.

FIGURE 3

Flanker task performance. (A) Erroneous responses, (B) reaction time (RT), and (C) RT variability with means and 95% confidence intervals are displayed for compatible and incompatible trials in adults with ADHD (black) and control adults (white). ADHD, attention-deficit/hyperactivity disorder.

FIGURE 4

ERP amplitudes. Stimulus-locked ERP mean amplitudes for (A) N2 and (B) P3 in compatible and incompatible trials by group. Response-locked ERP mean amplitudes for (C) ERN and (D) Pe for correct and erroneous responses by group.

FIGURE 5

Associations between ASRS scores and ERP amplitudes and behavioral measures in the ADHD group. (A) Positive correlations of error-rates for incompatible trials and total (r = 0.52, p = 0.006) and inattentive ASRS scores (r = 0.44, p = 0.02). (B) Negative correlation of incompatible P3 correlated with total (r = –0.44, p = 0.02) and inattentive ASRS scores (r = –0.52, p = 0.005). (C) Positive correlation of ERN and total (r = 0.44, p = 0.02) and inattentive ASRS scores (r = 0.40, p = 0.04).