Table 2.

Overview of outcome measures used in included studies.

Measure	Definition
PSQI	24-item self-report measure of sleep quality. Range: 0–21. Score >6 indicates poor sleep. (Buysse et al., 1989)
SOL	Measured by sleep diary or polysomnogram; length of time (minutes) from turning light off to falling asleep. SOL ≤30 min is normal.
WASO	Measured by sleep diary or polysomnogram; length of time (minutes) of wakefulness after initial onset of sleep. WASO ≤30 min is normal.
TST	Measured by sleep diary or polysomnogram; length of time (minutes) spent sleeping while in bed.
TWT	Measured by sleep diary or polysomnogram; length of time (minutes) of wakefulness during the in-bed period.
SE	Measured by sleep questionnaire, sleep diary, or polysomnogram; percentage of time asleep while in bed.
ISI	7-item self-report measure of insomnia severity. Range: 0–28. A change in score >7 is clinically meaningful and a score ≥11 indicates insomnia. (Morin, 1993; Morin et al., 2015)
Sleep Quality	Item from sleep diary (“How would you rate the quality of your sleep?“), rated on a 5-point Likert scale from “very poor” to “very good”.
Nighttime awakenings	The discrete number of nighttime awakenings recalled by an individual.
Hypnotic-free nights/week	The number of nights per week that an individual did not use hypnotic medications for sleep.
Enjoyment of sleep	Enjoyment of sleep rated on a 5-point Likert scale from 0 (not at all) through 4 (extremely).

Abbreviations: ISI = insomnia severity index, PSQI = Pittsburgh Sleep Quality Index, WASO = wake after sleep onset, SOL = sleep onset latency, SE = sleep efficiency, TST = total sleep time, TWT = total wake time.