Executive functioning is frequently impaired among people with Parkinson's disease (PD). Little is known about awareness of executive functioning, in the sense of being able to accurately appraise functioning or performance, in people with PD, or about whether awareness is particularly affected in those who have impaired executive functioning. This study explored awareness of executive functioning at the levels of evaluative judgment (comparison of self- and informant ratings of executive functioning), and performance monitoring (comparison of performance on cognitive tests and self-ratings of that performance). Awareness levels were assessed in people with PD with and without executive deficits, and in healthy controls. When the level of agreement between self- and informant ratings was considered, people with PD in both groups appeared as accurate in evaluating their overall executive functioning as healthy controls. When appraising their performance as the specific tasks were completed, people with PD who had impairments in executive functioning appeared less accurate than controls and people with PD without executive impairments. People with PD who have executive deficits may lack the ability to recognize their limitations while performing specific tasks, which may have implications for their functional abilities. (JINS, 2013, 19, 1–12.)

Literature suggests that individuals with mild traumatic brain injury (mTBI) show subtle abnormalities in the cognitive control process of performance monitoring. The neural bases of performance monitoring can be measured using the error-related negaitivity (ERN) and post-error positivity (Pe) components of the scalp-recorded event-related potential (ERP). Thirty-six individuals with mTBI and 46 demographically similar controls completed a modified color-naming Stroop task while ERPs were recorded. Separate repeated-measures analyses of variance were used to examine the behavioral (response times [RT] and error rates) and ERP (ERN and Pe amplitudes) indices of performance monitoring. Both groups showed slower RTs and increased error rates on incongruent trials relative to congruent trials. Likewise, both groups showed more negative ERN and more positive Pe amplitude to error trials relative to correct trials. Notably, there were no significant main effects or interactions of group for behavioral and ERP measures. Subgroup and correlational analyses with post-concussive symptoms and indices of injury severity were also not significant. Findings suggest comparable performance to non-injured individuals in some aspects of cognitive control in this sample. Neuropsychological implications and comparison with other cognitive control component processes in individuals with TBI are provided. (JINS, 2012, 18, 323–333)

The nature of error detection as manifested by the error-related negativity was examined in both a Sternberg memory search task and a visual search task. Both tasks were performed in conditions with consistent or varied stimulus–response mapping and loads of three or six letters. After subjects were trained extensively in all conditions, they performed the tasks throughout the night without sleeping. The data suggest that the effectiveness of error detection decreases over time because of a decrease in the quality of perceptual processing. Error detection also suffers when performance requires more search-related resources. In both cases, the representation of the correct response is compromised. These results indicate that error detection depends on the same perceptual and cognitive processes that are required for correct performance.