“…Data also exists about its prevalence in general population. Methods employed ranged from questionnaires 5,6,8–10,12–14,16,18–21,24,25,29–32,34,38–40,42,44,47,48,51,52,55,56,59,60,63,64,67,70–75,80,82,84,87,88,90–97,99–104 , home testing to overnight sleep studies 34,49,51,52,55,58–66,68,69,98,99 . In some studies, screening using questionnaires was done followed by polysomnography 10,26,48,51,52,59,64,99 .…”