1. Sleep Disorders Centre, Department of Pulmonology, Atatürk Chest Diseases and Chest Surgery Education and Research Hospital, Ankara, Turkey
2. Department of Pulmonology, Gazi University, Faculty of Medicine, Ankara, Turkey
3. Department of Biochemistry, Numune Training and Education Hospital, Ankara, Turkey
4. Sleep Medicine Unit, Department of Neurology and Rehabilitation Medicine, Skoevde, Sweden