Table 3 Sleep parameters of the three study nights for nightmare sufferers (NM) and healthy controls (HC)

Sleep period time (min)

453.73 ± 59.57

453.35 ± 68.57

454.70 ± 48.86

462.55 ± 72.73

430.11 ± 42.16

464.35 ± 54.12

Sleep efficiency (%)

83.51 ± 9.19

84.99 ± 7.06

90.99 ± 3.23

88.21 ± 7.08

90.28 ± 3.82

90.47 ± 4.25

Sleep onset latency (min)

18.76 ± 13.51

22.50 ± 23.87

15.26 ± 9.55

18.85 ± 16.90

16.97 ± 13.25

16.82 ± 11.46

REM latency (min)

105.47 ± 50.44

104.32 ± 48.36

78.79 ± 37.48

94.50 ± 40.95

81.47 ± 31.87

99.88 ± 43.70

REM density

20.78 ± 6.45

18.86 ± 5.44

21.06 ± 5.07

20.52 ± 5.71

21.11 ± 6.90

19.50 ± 6.41

Number of awakenings

26.94 ± 10.07

23.82 ± 8.79

24.82 ± 9.36

24.59 ± 10.89

22.41 ± 6.22

26.35 ± 9.17

Number of REM periods

3,06 ± 0,899

2,94 ± 0,966

3,82 ± 0,636

3,53 ± 1,419

3,29 ± 1,213

3,41 ± 1,004

Arousal Index

10.68 ± 3.64

8.78 ± 1.86

10.38 ± 3.35

9.09 ± 2.04

9.33 ± 2.62

9.75 ± 2.06

Awake%

11.45 ± 7.58

9.54 ± 5.33

5.67 ± 2.88

6.48 ± 5.05

5.76 ± 2.72

5.82 ± 3.59

Stage N1%

9.22 ± 3.03

8.03 ± 3.91

8.33 ± 3.92

8.20 ± 3.96

8.39 ± 3.93

9.00 ± 2.94

Stage N2%

42.74 ± 5.92

46.41 ± 6.18

45.25 ± 7.62

46.50 ± 9.01

45.01 ± 6.77

47.35 ± 7.11

Stage N3%

22.48 ± 9.24

20.77 ± 11.04

23.96 ± 9.30

20.95 ± 9.68

24.75 ± 7.87

21.57 ± 9.52

Stage REM%

13.92 ± 3.60

14.70 ± 3.85

16.75 ± 3.84

15.41 ± 4.21

16.05 ± 3.68

16.20 ± 3.70

Arousal Index (REM only)

9.85 ± 5.05

7.57 ± 3.47

9.66 ± 4.77

9.20 ± 4.43

10.37 ± 5.24

8.15 ± 4.23

Periodic leg movements

3.00 ± 6.36

1.95 ± 3.81

Periodic leg movements with arousal

0.18 ± .59

0.23 ± .50