1. Stanford Neurocritical Care Program, Stanford Stroke Center, Stanford University School of Medicine Center, Palo Alto, CA 94304, USA
2. Stroke Washington Hospital Center, Washington, DC 20010, USA
3. Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
4. Department of Neurology, NorthShore University Health System, The University of Chicago, Evanston, IL 60201, USA