1. Department of Radiology, University of Michigan , Ann Arbor, MI 48109 , USA
2. Department of Neurology, University of Michigan , Ann Arbor, MI 48109 , USA
3. Parkinson’s Foundation Research Center of Excellence, University of Michigan , Ann Arbor, MI 48109 , USA
4. Morris K. Udall Center of Excellence for Parkinson’s Disease Research, University of Michigan , Ann Arbor, MI 48109 , USA
5. Institute for Kinesiology Research, Science and Research Centre Koper , 6000 Koper , Slovenia
6. Department of Health Sciences, Alma Mater Europaea—ECM , 2000 Maribor , Slovenia
7. Neurology Service and GRECC, VA Ann Arbor Healthcare System , Ann Arbor, MI 48105 , USA