David A Kalmbach1, Srijan Sen2, Christopher L Drake3. 1. Thomas Roth Sleep Disorders & Research Center, Henry Ford Health System, Detroit, MI, USA. Electronic address: dkalmbac@gmail.com. 2. Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA. 3. Thomas Roth Sleep Disorders & Research Center, Henry Ford Health System, Detroit, MI, USA.