Latency to REM(dreaming) from sleep onset.
The length of time between the onset of sleep and the first REM sleep period, used as an aid in the diagnosis of narcolepsy. REM latency is less than 20 minutes in approximately 50% of narcoleptics compared to about 90 minutes in normal individuals.
the period of time in the sleep period from sleep onset to the first appearance of REM sleep.
Minutes elapsed from SO to REM sleep.
Number of minutes from sleep onset to the first epoch of REM sleep.