Aged 1 Article 1 Female 1 Humans 1 MRI 1 Magnetic Resonance Imaging 1 Male 1 Middle Aged 1 Mini Mental State Examination 1 Multiple System Atrophy Parkinson disease 1 Shy Drager syndrome 1 Unified Parkinson Disease Rating Scale 1 White Matter 1 adult 1 aged 1 alpha synuclein 1 axial diffusivity 1 clinical article 1 cognition 1 controlled study 1 diagnostic imaging 1 diffusion tensor imaging 1 diffusion weighted imaging 1 echo planar imaging 1 female 1 fractional anisotropy 1 human 1 image processing 1 in vivo study 1