Sensitivity to negative-feedback processing in people with Parkinson's disease and impulsive-compulsive behaviours.

Biomarkers of impulsive compulsive behaviours (ICBs) in Parkinson’s disease (PD) are lacking. We combined behavioural and electrophysiological markers of sensitivity to negative feedback to address this lack of knowledge. Eighteen PD patients (ICB+, N = 8; ICB-, N = 10) underwent electroencephalography during the Balloon Analogue Risk Task (BART), a measure of risky behaviour, and the feedback-related negativity (FRN), a measure of negative feedback processing, was recorded. Participants also completed the Questionnaire for Impulsive-Compulsive Disorders in Parkinson’s Disease Rating Scale (QUIP-rs), and underwent cognitive, affective and motivation measures. Behaviour on the BART and FRN measures did not differ between the ICB + and ICB- groups. However, a significant positive correlation was observed between the amplitude of the FRN at the Cz electrode and the BART discrepancy score when the two groups were combined into one PD group (rs(18) = 0.52, p = 0.03; 95% CI = 0.07, 0.80). No additional correlations were found between FRN amplitudes and the QUIP-rs score, nor with cognitive, affective, or motivational measures. Our findings indicate that, regardless of ICB status, PD patients may be able to process negative feedback to mitigate risky behaviour during reward-related decision-making. We observed that a higher feedback-related negativity (FRN) is linked to a decrease in risky behaviour following a balloon burst. However, due to the small sample size, these findings should be interpreted with caution. Future studies should explore both positive and negative feedback processing using a task that maintains the dynamics of the ongoing decision-making process while increasing risk.