1. Sleep Disorders Center, Department of Respiratory Medicine, University of Crete, Heraklion, Greece;
2. Department of Sleep Medicine, Sahlgrenska University Hospital, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden;
3. Department of Respiratory and Sleep Medicine, St. Vincent's University Hospital, School of Medicine, University College, Dublin, Ireland;
4. Antwerp University Hospital, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium;
5. Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy;
6. Department of Chest Diseases, Ege University Faculty of Medicine, Izmir, Turkey;
7. Department of Respiratory Medicine, Respiratory Failure Unit, G. Papanikolaou Hospital, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece;
8. National Research Council (CNR), Istituto per la Ricerca e l'Innovazione Biomedica, Palermo, Italy;
9. Sleep Unit, Department of Pneumonology, Democritus University of Thrace, Alexandroupolis, Greece;
10. Dipartimento di Promozione della Salute, Materno-Infantile, Medicina Interna e Specialistica di Eccellenza (PROMISE), University of Palermo, Palermo, Italy; *Contributed equally