1. Division of Pulmonary and Sleep Medicine, Bethesda North Hospital, Cincinnati, Ohio;
2. Bethanien Hospital Clinic of Pneumology and Allergology, Center for Sleep Medicine and Respiratory Care, Institute of Pneumologie at the University of Cologne, Solingen, Germany; and
3. Division of Pulmonary, Critical Care, and Sleep Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico