Prodromal Parkinson's Disease: What We Know and What We do Not Know

Prodromal Parkinson's Disease (PD) represents a critical phase preceding the clinical onset of the disease, characterized by subtle and often non-motor symptoms that precede the classic motor manifestations. Understanding this prodromal phase is essential for early diagnosis, intervention, and potentially altering the disease course. This narrative review aims to elucidate the current knowledge on the prodromal phase of PD, highlighting known biomarkers, genetic predispositions, and environmental factors that contribute to early detection. Furthermore, it examines the limitations and gaps in our understanding, including the variability in prodromal symptoms, challenges in identifying definitive biomarkers, and the need for longitudinal studies. By synthesizing the existing literature, this review provides a comprehensive overview of what we know about prodromal PD and underscores the areas that require further research to enhance early diagnostic accuracy and develop preventative strategies.