Table 3.

Sleep Quantity and Quality Measuresin Relation to Cognitive Test Scores

Cognitive Test	Sleep Measure		Estimate f	Std. Error	p value
MMSE (points) a	Sleep quantity e
	Short (<7 hours)		0.624	0.495	0.21
	Long (>8 hours)		−1.141	0.433	<0.01*
	Sleep somnolence		−0.016	0.013	0.19
	Sleep problems index II		0.006	0.020	0.75
	Sleep adequacy		−0.009	0.021	0.67
CVLT (words) b	Sleep quantity e
	Short (<7 hours)		0.400	0.390	0.31
	Long (>8 hours)		−0.992	0.342	<0.01*
	Sleep somnolence		0.002	0.011	0.85
	Sleep problems index II		0.007	0.016	0.68
	Sleep adequacy		−0.017	0.017	0.32
BNT (items) c	Sleep quantity e
	Short (<7 hours)		0.077	0.339	0.82
	Long (>8 hours)		0.015	0.304	0.96
	Sleep somnolence		0.009	0.009	0.34
	Sleep problems index II		0.015	0.013	0.25
	Sleep adequacy		−0.007	0.015	0.61
TMT B (seconds) d	Sleep quantity e
	Short (<7 hours)		−4.859	16.039	0.76
	Long (>8 hours)		34.969	14.479	0.02*
	Sleep somnolence		0.345	0.467	0.46
	Sleep problems index II		−0.084	0.689	0.90
	Sleep adequacy		−0.422	0.680	0.54

Abbreviations: MMSE, mini-mental state examinations; CVLT, California verbal learning test; BNT, Boston naming test;TMT B, trails making test B

^*p<0.05 indicates significance

Notes:

^aScored as number of points, with higher score indicating better performance.

^bScored as number of words recalled, with higher score indicating better performance.

^cScored as number of items correct, with higher score indicating better performance.

^dScored as time to completion in seconds, with lower score indicating better performance.

^eParticipants in the short sleep (<7 hours) and long sleep (>8 hours) categories are compared to participants in the optimal sleep group (7–8 hours).

^fEvery unit increase in the sleep measure is associated with an increase or decrease (−) in units of the cognitive measure.