Table 5.

Comparison of SDI and non-sleep variables for subjects with <6 h or 6 NTST, and unadjusted P-value

	Less than 6 h TST (n = 44)	6 h+ TST (n = 58)	Unadjusted P-value
Age	75.2 (8.1)	75.6 (9.1)	0.791
Gender (% female)	43.2%	51.7%	0.392
Education (years)	12.3 (4.0)	13.0 (3.8)	0.434
Duration of AD (years)	5.3 (3.5)	4.2 (2.4)	0.060
MMSE	14.6 (9.2)	16.6 (7.6)	0.232
ADAS	38.3 (20.9)	31.0 (16.1)	0.066
ADL	39.1 (22.2)	42.9 (22.7)	0.398
Hamilton	7.7 (3.6)	7.7 (3.5)	0.908
NPI	25.0 (18.1)	15.8 (15.1)	0.006
SDI score (avg. frequency × avg. severity)	4.3 (2.3)	3.0 (1.9)	0.002*
Average frequency rating	2.2 (.8)	1.8 (.7)	0.009
Average severity rating	1.9 (.5)	1.6 (.5)	0.003*
Average CG distress rating	2.5 (1.2)	1.8 (1.0))	0.002*
Number of SDI symptoms present	4.3 (1.6)	3.6 (1.6)	0.007
Sleep quality rating (average)	2.9 (0.7)	3.2 (0.7)	0.043

Values are expressed as mean (SD).

^*Holm-adjusted P-value < 0.05; n = 102 as two subjects had no actigraphy.

TST, total sleep time; AD, Alzheimer’s Disease; MMSE, Mini-Mental State Examination; ADAS, Alzheimer’s Disease Assessment Scale; ADL, activities of daily living; NPI, Neuropsychiatric Inventory; SDI, Sleep Disorders Inventory; Avg, the average over the seven items for an individual; CG, caregiver.