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. Author manuscript; available in PMC: 2015 Mar 24.
Published in final edited form as: J Sleep Res. 2006 Mar;15(1):97–103. doi: 10.1111/j.1365-2869.2006.00499.x

Table 2.

Sleep symptoms: mean ± SD frequency ratings and endorsement rates (%) for SP+, SP− by cohort

SDSQ symptom Frequency‡
Endorsement§
Non-demented
Poss/prob AD
Non-demented
Poss/prob AD
SP+ SP− SP+ SP− SP+ SP− SP+ SP−
(1) Number of wake-ups per night 2.7 ± 1.1 2.7 ± 1.1 2.5 ± 1.2 1.9 ± 1.1* 93.0 86.2 92.9 78.0+*
(2) Drowsy during the day 1.9 ± 1.1 1.7 ± 1.1 2.3 ± 1.1 1.9 ± 1.1* 66.2 60.4 75.7 64.8
(3) Takes naps during the day 1.8 ± 1.1† 1.8 ± 1.2 2.5 ± 1.2 2.0 ± 1.2+* 60.8† 59.4 77.8 68.7
(4) Equal sleep time day = night 0.2 ± 0.6† 0.1 ± 0.2 0.8 ± 1.2 0.3 ± 0.7* 2.8† 2.5 20.6 5.6*
(5) Takes >30 min to fall asleep 2.2 ± 1.1 1.2 ± 1.0* 1.6 ± 1.3 0.7 ± 0.9* 76.4† 34.5* 52.2 14.9*
(6) Wakes up during night for >1 Hr 2.2 ± 1.0† 1.1 ± 1.0* 1.5 ± 1.1 0.7 ± 0.8* 81.9† 33.1* 51.5 13.3*
(7) Wakes up too early 2.1 ± 1.1 1.2 ± 1.0* 2.0 ± 1.1 0.9 ± 0.9* 73.5 38.1* 66.2 24.1*
(8) Restless sleep 1.7 ± 1.0 1.0 ± 0.9* 1.8 ± 1.0 1.0 ± 0.9* 57.4 26.2* 56.1 24.3*
(9) Lies awake tense/worried 1.2 ± 1.0 0.8 ± 0.8* 1.6 ± 1.1 0.7 ± 0.8* 33.3 17.5+* 50.8 17.2*
(10) Snores heavily 0.7 ± 1.1† 0.9 ± 1.2 1.4 ± 1.4 1.2 ± 1.2 20.4+† 29.6 46.9 36.5
(11) Has trouble breathing 0.3 ± 0.6 0.3 ± 0.7 0.7 ± 1.1 0.3 ± 0.8* 7.4 6.0 21.0 7.7
(12) Breathes irregularly 0.2 ± 0.6† 0.3 ± 0.8 0.8 ± 1.1 0.4 ± 0.9+* 8.2 8.2 24.1 11.8
(13) Twitches/jerks in sleep 0.7 ± 0.9 0.5 ± 0.8 1.2 ± 1.4 1.1 ± 1.2 19.3 14.1 33.3 35.8
(14) Wakes up with headache 0.5 ± 0.9 0.4 ± 0.7 0.7 ± 1.0 0.5 ± 0.8 15.5 8.4 20.0 12.7
(15) Wakes at night with pain 1.0 ± 1.0† 0.6 ± 0.9* 0.5 ± 0.9 0.5 ± 0.8 30.4 16.6 13.3 12.1
(16) Uses medication to help get to sleep 1.0 ± 1.0 0.3 ± 0.7* 0.8 ± 1.3 0.3 ± 0.7* 37.5 10.0* 25.0 7.2*
(17) Uses alcohol to help get to sleep 0.1 ± 0.2 0.1 ± 0.3 0.0 ± 0.4 0.0 ± 0.3 0.0 1.3 1.5 0.6
(18) Has bowel/bladder problems at night 2.0 ± 1.3 1.5 ± 1.4* 1.8 ± 1.4 1.0 ± 1.3* 62.7 45.8 55.2 27.1*
(19) Has muscle cramps during sleep 1.4 ± 1.0 1.1 ± 1.0 0.9 ± 0.8 0.8 ± 0.9 46.5 38.3 29.7 23.6
(20) Has restless legs during sleep 1.5 ± 1.0 0.9 ± 1.1* 0.9 ± 1.2 0.6 ± 0.9 54.8 30.9 25.0 17.6
(21) Awakes feeling well rested 2.8 ± 1.0 3.2 ± 1.0* 2.5 ± 1.1 3.2 ± 1.0* 91.7 91.6 77.0 91.3

Non-demented are healthy elderly subjects with normal cognitive function at the time of sleep symptom assessment. Poss/prob AD: individuals met NINCDS-ADRDA criteria for possible or probable Alzheimer’s disease. Sample sizes given reflect number of respondents, however, the numbers for whom each variable were recorded varied. SP+: Endorsed ‘sleep problems’; SP−: did not endorse ‘sleep problems’. Frequency ratings compared by Mann–Whitney non-parametric comparison; endorsement compared by chi-square;

*

indicates Holm-adjusted P < 0.05 for SP+ versus SP− within the cohort;

†

indicates Holm-adjusted P < 0.05 for AD SP+ versus NDE SP+ (across cohorts);

+*

indicates Holm-adjusted P-value for SP+ versus SP− is marginally not significant,

+†

indicates Holm-adjusted P-value for AD SP+ versus NDE SP+ is marginally not significant (range: 0.059–0.08; see text for values).

‡

Frequency (ratings for ‘in previous months’): 0, never; 1, less than once per month; 2, at least once per month; 3, at least once per week; 4, nearly every day/night).

§

Endorsement: ratings of at least once per month (2–4) – ‘endorsed’; ratings of never/less than once per month (0 or 1) – ‘un-endorsed’.