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Table 1 Selected sleep stage variables in healthy controls and chronic fatigue syndrome patients without sleep abnormalities

From: Sleep structure and sleepiness in chronic fatigue syndrome with or without coexisting fibromyalgia

 

Healthy

Chronic fatigue syndrome

Number

26

26

Age, years

38 ± 8

39 ± 8

Body mass index, kg/m2

24.4 ± 4.8

24.9 ± 5.2

CES-D score

8 ± 7

17 ± 8a

Sleep structure

  

Time in bed, minutes

453 ± 33

438 ± 42

Total sleep time, minutes

385 ± 39

351 ± 54a

Sleep efficiencyb, percentage

85 ± 8

80 ± 10a

Number of arousals per hour

8.2 ± 5.2

5.7 ± 4.9

Wakefulness, minutes

51 ± 38

61 ± 32

Stage 1, minutes

44 ± 18

33 ± 17a

Wakefulness plus stage 1, minutes

96 ± 43

94 ± 35

Stage 2, minutes

225 ± 36

198 ± 33a

Stage 3, minutes

29 ± 20

46 ± 23a

Stage 4, minutes

5 ± 11

10 ± 15

Slow-wave sleep (stage 3 + 4), minutes

34 ± 26

56 ± 34

Stage REM, minutes

84 ± 25

64 ± 26a

Sleep latencyc, minutes

16 ± 18

26 ± 26

REM latencyd, minutes

105 ± 49

127 ± 65

Median duration of sleep runs, minutes

15.6 ± 18.4

8.9 ± 5.7a

Likert scale (0–15.5)

  

   Sleepiness

  

Evening

6 ± 4

9 ± 5a

Morning

1 ± 2e

8 ± 4a

   Fatigue

  

Evening

4 ± 4

11 ± 3a

Morning

2 ± 2e

9 ± 4a

   Pain

  

Evening

1 ± 2

7 ± 5a

Morning

0 ± 1

7 ± 5a

   Feeling blue

  

Evening

1 ± 2

2 ± 2

Morning

0 ± 0e

1 ± 3a

  1. Values are presented as mean ± standard deviation. aSignificantly different from healthy controls (P < 0.05, non-paired t test). bTotal sleep time/time in bed × 100%. cTime from lights out to sleep onset. dTime from lights out to first epoch of stage REM. eSignificantly different from evening (P < 0.05, paired t test). CES-D, Centers for Epidemiological Study-Depression; REM, rapid eye movement.