Sleep, Actually
REM latency
How long after falling asleep the first REM period begins.
REM latency is the gap between falling asleep and the first REM period. Typically REM arrives some way into the night, after passing through non-REM stages.
REM appearing unusually soon after sleep onset is one of the features sleep specialists pay attention to during testing. In MSLT scoring, such an episode is described as a sleep-onset REM period, often shortened to SOREMP.
Whether that pattern means anything for a particular person is a clinical judgement, made alongside an overnight study and a full history.
Definitions on this page
- REM latency
- Time from falling asleep to the first REM period.
- SOREMP
- Sleep-onset REM period — REM appearing very soon after falling asleep, as scored during testing.
Nearby
More in this part of the hub
Sleep latency
How long it takes to fall asleep after the lights go out.
Sleep efficiency
The proportion of time in bed that was actually spent asleep.
Polysomnography — the overnight sleep study
An overnight recording of brain activity, breathing, heart rhythm, eye movement, and muscle activity while you sleep.
Multiple Sleep Latency Test (MSLT)
A daytime test of scheduled nap opportunities, measuring how quickly you fall asleep and whether REM appears.