This study focuses on finding reliable **biomarkers** for early diagnosis of Parkinson's Disease (PD) and Atypical Parkinsonian Syndrome (APS) using a method called **metabolomics**. Metabolomics studies the tiny chemicals called metabolites in our body, to see how they change in diseases like PD and APS. The method we'll use is called **proton nuclear magnetic resonance (NMR) spectroscopy**, which helps us look at many metabolites at once without destroying the sample. Parkinson’s Disease is a brain disorder that worsens over time, affecting movement and leading to serious health issues. APS includes conditions similar to PD, making it hard to tell them apart early on. By studying blood serum, which is safer to collect than spinal fluid, researchers hope to find markers that can help diagnose these diseases earlier and more accurately. **Key Points:** - Age range for participants is 45-80 years. - The study involves analyzing blood samples using NMR. - Understand the risks and benefits of participating, as this study may not involve direct treatment. Participants must meet specific criteria and cannot have other conditions like hereditary Parkinson's or past surgeries like deep brain stimulation.