Pain and fatigue in Parkinson's disease: advances in diagnosis and management

Non-motor symptoms affect over 90% of people with Parkinson's disease at all stages, with pain and fatigue being among the most prevalent yet often neglected in clinical practice. Despite their significant impact, these symptoms are frequently underdiagnosed and inadequately treated, adding substantial burden to patients' lives. The lack of a clear definition and classification of these symptoms has led neurologists to underestimate their presence among people with Parkinson's disease and limited the ability to address them with mechanism-based care and effective treatments. Managing these symptoms is challenging because of the lack of robust, specifically designed, randomized-controlled trials on effective treatments. This review delves into the current understanding of diagnosing, assessing, and treating pain and fatigue in Parkinson's disease, highlighting critical knowledge gaps and suggesting future research directions. The framework emphasizes improving classification methods, deepening our understanding of the underlying pathophysiology, evaluating treatment impacts on pain and fatigue, and leveraging longitudinal data collection through consensus-based methodology. By addressing these critical areas, we strive to enhance the management of these debilitating non-motor symptoms and ultimately improve patients' quality of life.