Shanghai Clinical Cohort - Parkinson's Disease (Reserve)

The goal of this observational cohort studyis to establish a high-quality clinical cohort of Parkinson's disease (PD) and multiple system atrophy (MSA) patients in Shanghai, in order to improve early diagnosis, precise subtyping, disease monitoring, and to provide a resource for translational research and novel therapy development. The main questions it aims to answer are: * Can multimodal data (clinical, imaging, electrophysiology, biospecimens, and genetics) help identify early biomarkers for PD and MSA? * Can precise subtyping and long-term monitoring predict disease progression and therapeutic response? Researchers will compare 600 PD patients and 100 MSA patients to evaluate differences in clinical features, biomarkers, imaging, and prognosis. Participants will: * Provide informed consent and complete baseline demographic and medical history collection. * Undergo standardized clinical evaluations, including motor and non-motor symptom scales, cognitive and quality-of-life assessments. * Provide biological samples (blood, saliva, optional CSF). * Receive brain imaging (MRI, optional PET/SPECT) and electrophysiological recordings (EEG, fNIRS). * Participate in longitudinal follow-up visits every 6 months for repeat assessments. This study will create a sustainable, multicenter, and sharable cohort platform to support early identification, personalized intervention, and therapeutic development for neurodegenerative diseases