Parkinson's disease (PD) is the second most common neurodegenerative disorder and frequently leads to oropharyngeal dysphagia, a swallowing disorder that strongly affects patient health and quality of life. Dysphagia in PD is associated with aspiration pneumonia, malnutrition, and impaired medication intake, which together represent one of the leading causes of morbidity and premature mortality in these patients. Despite its clinical relevance, the underlying biological mechanisms of dysphagia in PD are not fully understood, and current treatment strategies are limited. The purpose of this study is to investigate the clinical, biological, and neural determinants of oropharyngeal dysphagia in patients with PD, and to explore compensatory mechanisms of the brain that may counteract swallowing difficulties. We hypothesize that dysphagia in PD is linked not only to disease severity and progression but also to specific biological markers and neural plasticity in the swallowing network. This is a prospective, cross-sectional observational study including 100 patients with PD. Swallowing function will be systematically assessed using flexible endoscopic evaluation of swallowing (FEES), a gold standard method for detecting penetration and aspiration. Additional clinical data will be collected, including motor and non-motor symptoms, disease severity, and quality of life measures. Biological assessments will include blood-based biomarkers related to inflammation and neurodegeneration. Furthermore, functional magnetic resonance imaging (fMRI) will be used to examine cortical and subcortical activity patterns associated with swallowing and to identify potential compensatory activation in dysphagic and non-dysphagic patients. By integrating clinical, biological, and imaging approaches, this study aims to provide a comprehensive characterization of dysphagia in PD. The findings are expected to improve the understanding of disease mechanisms and to identify predictors of dysphagia onset and severity. Ultimately, this knowledge may help to guide the development of targeted therapeutic strategies, reduce the risk of severe complications, and improve quality of life for patients with Parkinson's disease.