Parkinson's disease and the concept of resilience, cognitive, and motor reserve.

Parkinson's disease (PD) shows pronounced clinical heterogeneity, with individuals presenting differing cognitive and motor trajectories despite similar levels of neurodegeneration, in particular striatal dopamine terminal loss. This variability underscores the relevance of considering resilience mechanisms, particularly cognitive and motor reserve, that may support preserved function in the face of progressive pathology and neurodegeneration. Building on a previously proposed conceptual framework of resilience in PD, this review provides an updated and integrative synthesis of recent evidence, including longitudinal studies, neuroimaging findings, and emerging insights into lifestyle-related factors. The review further extends the existing framework by addressing current methodological challenges and outlining future directions for incorporating resilience into neuroimaging research, biological staging models, and personalized intervention strategies in PD. Together, this work emphasizes the growing importance of resilience research in PD and its potential to improve prognostic accuracy and inform more precise and individualized therapeutic approaches.