Study Overview: This study is observing people with Atypical Parkinsonian Syndromes (APS). APS includes different conditions like MSA (Multiple System Atrophy), DLB (Dementia with Lewy Bodies), PSP (Progressive Supranuclear Palsy), and CBD (Corticobasal Degeneration). The study will look at how these conditions change over time, including both movement and non-movement symptoms. Researchers want to find signs, called biomarkers, that might predict these changes early.

Key Points:

• The study is observational, meaning no treatment is given, just monitoring.
• Participants must have had symptoms for ≤3 years for MSA, ≤2 years for PSP, and meet specific criteria for APS types.
• People with Parkinson's disease or other similar conditions can't join this study.