[1] Univ Athens, Dept Psychiat, Sleep Study Unit, 74 Vas Sofias Ave, Athens 11528, Greece
[2] Bioclin Hosp Athens, Enypn Sleep Epilepsy Ctr, 15 M Geroulanou St, Athens 11524, Greece
[3] Univ Vita Salute San Raffaele, Div Neurosci, Via Stamira dAncona 20, I-20127 Milan, Italy
[4] Democritus Univ Thrace, Sch Med, Dept Pulmomonolgy, Sleep Unit, Univ Campus, Dragana 68100, Alexandroupolis, Italy