H. Klar Yaggi, MD, MPH 
Division of Pulmonary and Critical Care Medicine, Yale University School of Medicine, 333 Cedar Street, PO Box 208057, New Haven, CT 06520-8057, USA, West Haven VA Medical Center Sleep Laboratory, VA CT Health Care System Clinical Epidemiology Research Center, 950 Campbell Avenue, West Haven, CT 06516, USA
Teofilo L. Lee Chiong, MD 
Division of Sleep Medicine, Department of Medicine, National Jewish Health, 1400 Jackson Street, Denver, CO 80206, USA
Vahid Mohsenin, MD 
Department of Medicine, Yale University School of Medicine, Yale Center for Sleep Medicine, New Haven, CT, USA