1. The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
2. McGaw Bioethics Scholars Program, Center for Bioethics and Humanities, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
3. Division of Palliative Medicine, Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
4. Michigan Institute for Clinical and Health Research, University of Michigan, Ann Arbor, Michigan, USA.
5. Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA.
6. Department of Medicine, University of Rochester Medical Center, Rochester, New York, USA.
7. Cornell Center for Research on End-of-Life Care, Weill Cornell Medicine, New York, New York, USA.
8. Struthers Parkinson's Center, Golden Valley, Minnesota, USA.
9. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
10. Neurology, Radiology, Neuroscience, Physical Therapy and Occupational Therapy, Washington University in St. Louis, St. Louis, Missouri, USA.
11. Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA.
12. Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
13. Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, Michigan, USA.