Predicting Impulse Control Disorders in Parkinson Disease through Incentive Biomarkers

Area of Science:

• Neuroscience
• Clinical Neurology
• Psychiatry

Background:

• Impulse control disorders (ICDs) are a significant concern in Parkinson disease (PD).
• Predictive markers for ICD development in PD are crucial for early intervention.
• The feedback-related negativity (FRN), a neurophysiological marker of incentive processing, has not been extensively studied in relation to ICDs in PD.

Purpose of the Study:

• To investigate whether the FRN can predict the future development of ICDs in patients with Parkinson disease.
• To assess the utility of FRNdiff, a measure derived from FRN signals during a gambling task, as a predictive biomarker for ICDs in PD.

Main Methods:

• A longitudinal cohort of nondemented PD patients without a history of ICDs was recruited.
• FRN signals were recorded during a gambling task, and FRNdiff (difference between losses and gains) was calculated.
• Patients underwent biannual follow-up for 30 months to detect incident ICDs, with survival models used for analysis.

Main Results:

• Eighteen out of 92 patients developed ICDs during the 30-month follow-up.
• Baseline FRNdiff was significantly greater in patients who developed ICDs compared to those who did not (-2.33μV vs -0.84μV, p=0.001).
• FRNdiff significantly predicted ICD development, even after adjusting for dopamine replacement therapy, sex, and age (HR=0.74, p=0.035).

Conclusions:

• Differences in reward processing, as indicated by FRN signals, precede the development of ICDs in Parkinson disease.
• The FRN serves as a valuable neurophysiological marker for identifying PD patients at high risk of developing ICDs.
• This research offers a novel approach to early risk stratification for ICDs in the PD population.