1. Division of Pulmonary, Critical Care and Sleep Medicine, Division of Internal Medicine, University of KY College of Medicine, Lexington, Kentucky.
2. Division of Pulmonary, Critical Care and Sleep Medicine, Johns Hopkins University, Baltimore, Maryland.
3. Henry Ford Hospital/Wayne State College of Medicine, Henry Ford Hospital Sleep Center, Detroit, Michigan.
4. Department of Neurology, University of Michigan, Ann Arbor, Michigan.
5. Department of Psychiatry, College of Medicine Penn State University, Hershey, Pennsylvania.
6. Biobehavioral and Health Sciences Division, University of Pennsylvania School of Nursing, Philadelphia, Pennsylvania.