Error Processing in Attention Deficit Hyperactivity Disorder

Performance monitoring refers to the detection of errors and correct responses in ongoing performance and the subsequent cognitive and behavioural adjustment of one's performance. Adequate performance monitoring is crucial to self-regulation and reinforcement learning, both of which are dysfunctional in attention deficit hyperactivity disorder (ADHD). Although research has shown that children with ADHD adjust less than controls following errors, studies have not determined if this deficit is limited to performance monitoring of errors, termed error processing. One explanation for this deficit is that children with ADHD have a diminished ability to detect errors in their performance, suggesting that the provision of performance feedback would facilitate performance monitoring. Study 1 examined post-error and post-correct adjustment of reaction time in an ADHD and control group using a modified flanker task in two conditions, one with feedback and one without. Study 1 aimed to determine if ADHD participants display a general or specific performance monitoring deficit, and if any deficit could be improved by providing feedback. With feedback, ADHD participants showed similar post-correct adjustment, but significantly less post-error adjustment and accuracy than controls. Feedback significantly enhanced accuracy and post-error adjustment for controls, but not for ADHD participants. Results suggest that the ADHD deficit is specific to error processing and that it does not improve with feedback. Neurological theories and research denote the biological basis of error processing, proposing it as a marker of genetic risk (i.e., an endophenotype) for ADHD. Consistent with this hypothesis, Study 2 examined the familiality of error processing in ADHD participants, unaffected siblings of children with ADHD, and controls using the same methodology as Study 1. With feedback, ADHD participants and unaffected siblings displayed similar post-correct adjustment, but significantly less post-error adjustment and accuracy than controls. Notably, unaffected siblings and ADHD participants showed similarly atypical post-error adjustment and accuracy. Results indicate familiality of the error processing deficit in ADHD. Moreover, as post-error adjustment is a behavioral measure that is easily scalable and feasible for large-scale research, error processing as an endophenotype of ADHD is supported. Combined, results promote the inclusion of this deficit in the neurocognitive profile of ADHD.Ph.D