1. Department of Psychiatry and Behavioral Sciences, Keck School of Medicine, 1975 Zonal Ave, Los Angeles, CA 90033, USA
2. Department of Radiology, Southern California Permanente Medical Group, 4867 W. Sunset Blvd, Los Angeles, CA 90027, USA
3. Division of Otolaryngology-Head and Neck Surgery, Tripler Army Medical Center, 1 Jarrett White Rd, Honolulu, HI 96859, USA
4. Department of Psychiatry and Behavioral Sciences, Sleep Medicine Division, Stanford Hospital and Clinics, 450 Broadway St, Pavillion B., Redwood City, CA 94063, USA