1. Department of Otolaryngology Head and Neck Surgery, Walter Reed National Military Medical Center, Bethesda, MD, USA
2. Department of Otorhinolaryngology/Sleep Medicine Centre, Hospital CUF, 4100-180 Porto, Portugal
3. Centre for Research in Health Technologies and Information Systems (CINTESIS), University of Porto, 4200-450 Porto, Portugal
4. Tripler Army Medical Center, Department of Surgery, Division of Otolaryngology, Tripler AMC, Honolulu, HI, USA
5. Tripler Army Medical Center, Division of Otolaryngology, Sleep Surgery and Sleep Medicine, 1 Jarrett White Road, Tripler AMC, HI 96859, USA