Impulse control in Parkinson's disease: Distinct effects between action and choice

Aside from typical motor symptoms, impulse control issues related to engaging in actions or decision-making can manifest in Parkinson's disease (PD). The lack of direct comparisons between impulsive action and impulsive choice domains hinders a comprehensive understanding of impaired impulse control in this population. Therefore, the current review integrates findings across behavioural measures of impulsive action and choice in PD samples, both on and off dopaminergic medication. The qualitative review of studies revealed a distinction between the two impulsivity domains in the context of PD. While impulsive action impairments present in early, non-medicated PD and persist throughout the disease, impulsive choice deficits may only emerge after time on medication. Research on impulsive choice, especially in non-medicated PD, is limited, and the impact of medication status and disease progression on both domains remains inconclusive. We recommend that future studies integrate impulsive action and choice task types within the same sample and employ longitudinal designs to monitor how disease progression and corresponding medication changes affect impulse control over time.