| Possible MSA-P or MSA-C |
| Babinski sign with hyperreflexia |
| Stridor |
| Possible MSA-P* |
| Rapidly progressive parkinsonism |
| Poor response to levodopa |
| Postural instability within 3 years of motor onset |
| Gait ataxia, cerebellar dysarthria, limb ataxia, or cerebellar oculomotor dysfunction |
| Dysphagia within 5 years of motor onset |
| Atrophy on MRI scan of putamen, middle cerebellar peduncle, pons, or cerebellum |
| Hypometabolism on FDG-PET scan in putamen, brainstem, or cerebellum |
| Possible MSA-C¶ |
| Parkinsonism (bradykinesia and rigidity) |
| Atrophy on MRI of putamen, middle cerebellar peduncle, or pons |
| Hypometabolism on FDG-PET scan in putamen |
| Presynaptic nigrostriatal dopaminergic denervation on SPECT or PET scan |
