Definitions for "Sleep onset"
Keywords:  rem, nrem, narcolepsy, asleep, infancy
The first 90 seconds (3 `epochs) of uninterrupted sleep.
Difficulty falling asleep.
the transition from the awake to the sleep state, normally into NREM stage 1 (but in certain conditions, such as infancy and narcolepsy, into REM.) Most polysomnographers accept EEG slowing, reduction and eventual disappearance of alpha activity, presence of EEG vertex spikes and slow rolling eye movements (the components of NREM stage 1) as sufficient for sleep onset; others require appearance of stage 2 wave forms. (See sleep latency, sleep stages.)