1. Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland.
2. Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland.
3. Department of Psychology, University of Texas, Austin, Texas.
4. Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
5. Department of Psychiatry, Neurology, and Nursing, Division of Behavioral Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland.
6. Sleep Disorders Center, Department of Medicine, Walter Reed National Military Medical Center, Bethesda, Maryland.
7. Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.
8. University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
9. Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland.
10. Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland.
11. UCSF Brain and Spinal Injury Center, San Francisco, California.
12. Department of Neurosurgery, University of California, San Francisco, California.