A case of insufficient sleep syndrome.

All night polysomnographic evaluation (PSG) soon after admission and at the late period of admission revealed an atypically high sleep efficiency and a prolonged total sleep time. Sleep onset latency and distribution of REM and NREM sleep stages were like those of normal sleepers. On REM latency, while it was remarkably reduced (25.0 min) soon after admission and sleep onset REM period (SOREMP) was found, at the late period of admission it was prolonged and SOREMP was not found. Giving multiple sleep latency test with polysomnography, soon after admission subjective excessive daytime sleepiness had already improved and mean sleep latency (13.2 min) was within normal range. However, SOREMP appeared twice in five tests. We considered that the appearance at the early period of admission was the result of REM pressure growing.