1. Department of Neurology, University of Utah, Salt Lake City, Utah
2. Department of Neurology, Yale University, New Haven, Connecticut
3. Department of Neurology, University of Washington, Valley Medical Center, Seattle, Washington
4. Department of Radiology, University of Utah, Salt Lake City, Utah
5. Department of Neurology, New York University, New York, New York
6. Department of Neurosurgery, University of Virginia, Charlottesville, Virginia
7. Department of Neurosurgery, University of Utah, Salt Lake City, Utah
8. Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee