[1] Massachusetts Eye & Ear Infirm, Clin Outcomes Res Unit, Boston, MA 02114 USA
[2] Harvard Univ, Sch Med, Dept Otol & Laryngol, Boston, MA 02115 USA
[3] Penn State Univ, Coll Med, Hershey, PA USA
[4] Brigham & Womens Hosp, Sleep Disroders Lab, Boston, MA 02115 USA