1. Sleep Unit, Hospital Universitario de Burgos, Burgos, Spain
2. CIBER Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain
3. Hospital Universitario de Burgos (HUBU), Burgos, Spain
4. Hospital Universitario Valdecilla, Santander, Cantabria, Spain
5. Hospital Val D′Hebron, Barcelona, Spain
6. Hospital San Pedro de Alcantara, Cáceres, Spain
7. Research Department, Hospital Universitario Araba, BioAraba, Universidad del Pais Vasco, Medicine Department, Vitoria, Spain
8. Section of Sleep Medicine, Department of Pediatrics, Comer Children's Hospital, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL