Table 2.

Average sleep parameters for each instrument (N=62).

Instrument		Values
Polysomnography
	Total sleep time (min), mean (SD)	389.3 (77.9)
	Wake after sleep onset (min), mean (SD)	76.5 (55.4)
	sleep efficiency (%), mean (SD)	81.4 (12.4)
Zmachine
	Total sleep time (min), mean (SD)	377.3 (76.6)
	Wake after sleep onset (min), mean (SD)	109.3 (63.0)
	sleep efficiency (%), mean (SD)	72.2 (14.8)
Fitbit
	Total sleep time (min), mean (SD)	446.3 (94.5)
	Wake after sleep onset (min), mean (SD)	67.7 (23.3)
	Sleep efficiency (%), mean (SD)	91.2 (19.7)
Sleep logs
	Total sleep time (min), mean (SD)	345.1 (119.4)
	Wake after sleep onset (min), mean (SD)	78.7 (81.9)
	Sleep efficiency (%), mean (SD)	65.7 (23.5)