Spared error-related potentials in mild to moderate Parkinson's disease.

Several lines of evidence indicate that people with Parkinson's disease are impaired at detecting their own motor errors. In the present study, we use a component of the event-related brain potential called the error-related negativity (ERN) to ask whether a high-level, generic error-processing system is compromised in Parkinson's disease. We recorded the electroencephalogram (EEG) from nine patients with mild to moderate Parkinson's disease and from nine normal control subjects while they performed a choice reaction time task. We found that the amplitude of the ERN was the same for both populations, indicating that the error-processing system associated with the ERN is not severely compromised in this Parkinson's disease population. These results are discussed in terms of disease progression.