. Author manuscript; available in PMC: 2012 May 3.

Published in final edited form as: J Geriatr Psychiatry Neurol. 2011 Mar;24(1):50–59. doi: 10.1177/0891988710397548

Table 2.

Group differences in objective sleep quality measures

	Caregivers, Mean (SD) n = 20	Non-caregivers, Mean (SD) n = 20	Sig. (p)	Partial η ²
primary analysis
Sleep onset latency (min)^*	17.32 (21.18)	8.67 (13.15)	.039	.110
TST in Stage N1 (%)^*	22.79 (10.64)	17.80 (6.63)	.039	.110
TST in Stage N2 (%)	48.00 (8.32)	43.87 (8.97)	.151	.055
TST in Stage N3 (%)	11.42 (8.68)	15.47 (7.27)	.103	.070
TST in Stage R (%)^*	17.93 (8.54)	22.94 (7.04)	.029	.122
Secondary analysis
Time in bed (min)	480.69 (101.82)	473.16 (97.67)	.711	.004
Total sleep time (min)	409.52 (98.24)	428.71 (77.99)	.460	.015
Wake after sleep onset (min)	53.85 (64.97)	35.93 (28.09)	.459	.015
Arousals (#)	51.30 (24.68)	41.00 (13.17)	.221	.040
Sleep efficiency (%): NP	85.27 (12.49)	91.03 (4.01)	.330	-

p < .05

Abbreviations: NP = non-parametric test used due to violation of normality assumption, TST = total sleep time.