Background: Patient reports of ‘usual’ and ‘recent’ sleep positions are used by allied health professionals to direct the management of waking and nocturnal musculoskeletal symptoms. However no published studies have determined if self reports of sleep position are valid, consistent or reliable. An observational study was conducted at the Centre for Sleep Research of the University of South Australia. Twelve subjects, four in each of the age groups 18 to 39 years, 40 to 59 years and 60 years and over, without any known sleep disorders or sleep-disturbing medical or emotional problems participated in the study. Subjects spent two non-consecutive nights in a sleep laboratory, where an infra-red light source allowed their sleep position during the night to be recorded on video. Prior to retiring, subjects recorded the position in which they believed they spent the most time during a ‘usual’ nights sleep. In the morning, they recorded the position in which they believed they spent the most time during the recorded nights sleep. Videos were viewed in order to count the number of position shifts per night and to calculate the total amount of time each subject spent lying prone, supine and on their side. Subjects’ pre- and post-sleep questionnaire responses were then compared to the video record to determine validity, the amount of time spent in each sleep position was compared across the two nights to determine consistency and pre-and post-sleep questionnaire responses were compared to determine reliability of self reported sleep position. High correlation was found when comparing subjects’ self report of their common sleep positions with the video record. The sensitivity of self reported ‘usual’ night side lying sleep position was 89% and ‘last’ night reports 95%. Sleep position was consistent across repeated nights’ sleep, and there was good reliability between subjects’ self report of ‘usual’ (92%) and ‘last night’ (83%) sleep positions. This study reports high validity, reliability and consistency in self reports of ‘usual’ and ‘recent’ sleep positions
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