[1] VA Boston Healthcare Syst, Med Serv, Boston, MA USA
[2] Brigham & Womens Hosp, Dept Med, Div Sleep & Circadian Disorders, 75 Francis St, Boston, MA 02115 USA
[3] Brigham & Womens Hosp, Dept Neurol, Div Sleep & Circadian Disorders, 75 Francis St, Boston, MA 02115 USA
[4] Harvard Med Sch, Div Sleep Med, Boston, MA 02115 USA