Polysomnography (PSG) The probability of OSA was established at first on the base of Epworth Sleepiness Scale score. The evaluation of patients was performed in the Sleep Laboratory of the Department of Pulmonology, Allergology and Respiratory Oncology at the University of Medical Sciences in Poznan, Poland using a full-night polysomnographic monitoring system (EMBLA S4000, Remlogic, Denver, Colorado) with Somnologica studio 3.3.2 software (EMBLA, Broomfield, Colorado, United States). Standard electroencephalography monitoring, including frontal leads (F1, F2), central leads (C3, C4), occipital leads (O1, O2) and reference leads at the mastoids (M1, M2); electromyography and electrooculography methodology were performed according to The American Academy of Sleep Medicine (AASM) guidelines.