1. Department of Neurosurgery, University of Nebraska Medical Center, Omaha, Nebraska
2. Department of Neurology, University of California San Francisco, San Francisco, California
3. Division of Pulmonary, Critical Care and Sleep Medicine, Nebraska Medicine Sleep Center, Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska
4. Sleep Medicine Division, Department of Psychiatry and Behavioral Science, Stanford University, Stanford, California
5. Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado
6. Department of Neurosurgery, University of Pennsylvania School of Medicine, Richards Medical Research Laboratories, Pennsylvania Hospital, Philadelphia, Pennsylvania
7. Department of Surgery, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
8. Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, Colorado