A Meta-Analysis of Decision-Making Process in Parkinson’s Disease

Introduction: Parkinson's disease (PD) is a neurodegenerative disorder that affects 2-3% of the elderly population and is characterized by the loss of dopamine-producing neurons in the substantia nigra. The most commonly described symptoms affect the motor system, but there is increasing awareness of non-motor symptoms, such as decision-making (DM) impairment. In this context, impairment in DM, which may characteristic of patients with PD, would affect daily activities due to the difficulty in choosing between various alternatives. Method: According to the PRISMA statement, the present meta-analysis critically examined the difference in DM performance, taking into account its many characteristics, between patients with a diagnosis of Parkinson's disease and healthy controls. Results: Thirty-one studies met the eligibility criteria and were included in the quantitative synthesis. The results highlighted that decision-making in ambiguous and risky situations is impaired in individuals diagnosed with PD compared to healthy individuals. From the analysis of studies, it is clear that Parkinson's disease (PD) can lead people to prefer disadvantageous and riskier options, probably because an impulsive response may have prevented patients with PD from learning from feedback and, consequently, from using rational strategies. The meta-analysis highlights that those differences depend on pharmacological treatment: only patients in the ON phase show an impaired decision-making compared to healthy controls. Discussion: While both decision-making under risk and ambiguity can be impaired in patients with Parkinson's disease, the underlying neural mechanisms may vary between the two. Understanding these differences is crucial for developing targeted interventions to improve decision-making abilities and enhance the quality of life for individuals living with Parkinson's disease. It would also be important to monitor drug treatment during the later stages of the disease with the aim of preventing drug abuse and treating cognitive symptoms associated with dopaminergic drugs.