Polysomnography: The sleep testing room was a standard test room at the Sleep Medicine Research Center at Assuta Medical Center. Standard in-lab polysomnography was conducted using the Somnoscreen-polysomnography (PSG) type sleeping test instrument (Somnomedics, Germany). Sleep channels included: electroencephalography (EEG), electro-oculography (EOG), leg and chin electromyography (EMG), nasal breathing, chest breathing, diaphragm breath, snoring, electro-cardio-graphy (EKG), heart rate, blood oxygen saturation, and body position. Sleep data processing was performed by skilled and trained sleep technicians in accordance with of the Rechtschaffen and Kales criteria (1968). Sleep continuity parameters: latency to stage 1 (SL1) and stage 2 (SL2), percent wake after sleep onset (%WASO), index of awakenings, total sleep time (TST), time in bed (TIB), and sleep efficiency (SE). Sleep architecture parameters: percent stage 1 (%S1), stage 2 (%S2), REM (%REM), and SWS (%SWS), index of sleep stage changes and REM onset latency (ROL).