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. Author manuscript; available in PMC: 2019 Nov 1.
Published in final edited form as: Aging Clin Exp Res. 2018 Sep 3;30(11):1307–1318. doi: 10.1007/s40520-018-1030-x

Table 4.

Sleep Quantity and Quality Measures in Relation to Cognitive Test Scores for Cognitively Normal Subjects compared to Subjects with CIND/Dementia

Normal CIND/Dementia
Cognitive Test Sleep Measure Estimatef Std. Error p value Estimatef Std. Error p value
MMSE (points) a Sleep quantity e
 Short (<7 hours) 0.073 0.291 0.80 0.676 1.228 0.59
 Long (>8 hours) −0.098 0.287 0.73 −1.712 0.911 0.07
Sleep somnolence 0.004 0.008 0.65 −0.014 0.025 0.58
Sleep problems index II 0.008 0.012 0.52 0.024 0.040 0.55
Sleep adequacy −0.003 0.013 0.84 −0.002 0.057 0.98
CVLT (words) b Sleep quantity e
 Short (<7 hours) −0.081 0.351 0.82 1.119 0.989 0.27
 Long (>8 hours) −0.361 0.342 0.29 −1.727 0.722 0.02*
Sleep somnolence 0.003 0.010 0.75 −0.008 0.022 0.72
Sleep problems index II 0.010 0.015 0.49 −0.012 0.033 0.71
Sleep adequacy −0.005 0.016 0.77 −0.006 0.048 0.91
BNT (items) c Sleep quantity e
 Short (<7 hours) −0.373 0.283 0.19 1.760 1.056 0.11
 Long (>8 hours) 0.315 0.278 0.26 −0.764 0.788 0.34
Sleep somnolence 0.010 0.008 0.25 0.003 0.023 0.91
Sleep problems index II 0.005 0.012 0.71 0.033 0.032 0.32
Sleep adequacy −0.005 0.014 0.71 0.014 0.048 0.78
TMT B (seconds) d Sleep quantity e
 Short (<7 hours) 9.281 14.708 0.53 −145.257 111.114 0.25
 Long (>8 hours) 8.047 14.495 0.58 119.057 77.375 0.18
Sleep somnolence 0.395 0.424 0.36 2.958 1.470 0.08
Sleep problems index II 0.688 0.617 0.27 −3.127 2.331 0.22
Sleep adequacy −0.938 0.634 0.14 0.978 3.471 0.79

Abbreviations: MMSE, mini-mental state examinations; CVLT, California verbal learning test; BNT, Boston naming test;TMT B, trails making test B; CIND, cognitive impairment no dementia

*

p<0.05 indicates significance

Notes:

a

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

b

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

c

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

d

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

e

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

f

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