Table 1.

Definition of sleep-related terms used in data extraction.

Term	Definition		Estimated by polysomnography/electroencephalography	Estimated by actigraphy
Nights recorded	The number of the nights that sleep-related parameters were evaluated, multiplied by each participant.		+	+
TST	The total amount of time whilst asleep in bed, presented in hours.		+	+
SE	TST expressed as percentage of total time in bed. SE is used as an indicator of sleep quality, and a value of <85% is indicative of sleep disorders. SE = (TST/Time spent in bed) × 100.		+	+
Sleep onset latency	The time elapsed from laying down on the bed until N1 stage sleep onset, presented in minutes.		+	+
REM onset latency	The time elapsed from laying down on the bed until REM stage sleep onset, presented in minutes.		+	–
Wake after sleep onset	The total amount of wakefulness from N1 stage sleep onset until the final awakening, presented in minutes.		+	+
REM stage sleep	The stage of sleep during which REM and dreaming occurs, presented in minutes.		+	–
N1 stage sleepa	The first sleep stage, represented in minutes.		+	–
N2 stage sleepa	The second stage of sleep, represented in minutes.		+	–
N3 stage sleep	The third stage of sleep, often referred as “deep sleep”, presented in minutes.		+	–

Notes: The symbol “+” denotes that the sleep-related parameter can be measured by the specific sleep measure. The symbol “–” denotes that the sleep-related parameter can not be measured by the specific sleep measure.

^a The combination of N1 and N2 stages of sleep, often referred as “light sleep”.

Abbreviations: REM = rapid eye movement; SE = sleep efficiency; TST = total sleep time.