1. Department of Neurology, University of California, San Francisco, San Francisco, California.
2. Division of Palliative Medicine, Department of Medicine, University of California, San Francisco, San Francisco, California.
3. Departments of Neurology and Medicine, University of Colorado School of Medicine, Aurora, Colorado.
4. Department of Neurology, University of Alberta, Edmonton, Alberta, Canada.
5. Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado.
6. Department of Medicine and Palliative and Advanced Illness Research Center, University of Pennsylvania, Philadelphia.