Scorer observed periodic breathing for a period of at least 5 minutes during study.

Sleep duration is the interval between sleep onset time and lights on/out-bed time while asleep (i.e. total sleep time, TST), while in-bed period is the interval between lights off/in-bed time and lights on/out-bed time (i.e. time in bed, TIB).Percentage of time in bed that was spent sleeping, or the ratio of total sleep time to total time in bed, expressed as a percentage.