Table 5 Association between polysomnography sleep parameters and hippocampus volume (n = 159)

Nighttime sleep duration (h)

6.0

(5.3–6.9)

6.3

(5.8–7.1)

1.21 [0.84;1.74]

0.30

1.25 [0.87;1.80]

0.23

1.32 [0.89;1.95]

0.24

1.26 [0.87;1.83]

0.22

N1 sleep duration (min) ^a

23.3

(15.0-32.5)

22.0

(14.5–26.5)

0.89 [0.54;1.46]

0.64

0.86 [0.52;1.42]

0.56

0.86 [0.52;1.43]

0.56

0.86 [0.52;1.41]

0.55

% N1 sleep duration ^b

6.3

(4.1–9.3)

5.6

(4.3–7.3)

0.76 [0.41;1.43]

0.40

0.72 [0.39;1.35]

0.31

0.70 [0.37;1.35]

0.29

0.72 [0.38;1.34]

0.29

N2 sleep duration (min) ^c

223.3

(186.3–253.0)

235.0

(203.0-271.5)

1.23 [0.81;1.88]

0.34

1.21 [0.79;1.85]

0.38

1.23 [0.79;1.92]

0.36

1.23 [0.80;1.89]

0.35

% N2 sleep duration ^d

61.3

(55.3–66.5)

61.9

(58.8–68.7)

1.11 [0.71;1.74]

0.63

1.03 [0.65;1.63]

0.90

0.98 [0.60;1.58]

0.92

1.04 [0.66;1.66]

0.85

N3 sleep duration (min) ^e

38.5

(25.0–58.0)

46.0

(27.5–66.5)

1.17 [0.78;1.76]

0.44

1.30 [0.85;1.99]

0.22

1.36 [0.88;2.09]

0.17

1.29 [0.84;1.98]

0.24

% N3 sleep duration ^b

10.8

(7.4–16.1)

12.4

(7.1–16.7)

1.01 [0.75;1.37]

0.92

1.08 [0.80;1.47]

0.61

1.10 [0.80;1.51]

0.56

1.07 [0.78;1.46]

0.68

REM sleep duration (min) ^e

72.8

(57.3–89.0)

70.0

(51.0-81.5)

1.02 [0.68;1.54]

0.92

1.08 [0.71;1.64]

0.71

1.17 [0.75;1.83]

0.49

1.10 [0.72;1.68]

0.66

% REM sleep duration ^b

20.0

(16.0-23.2)

18.4

(13.3–21.4)

0.94 [0.67;1.33]

0.73

0.97 [0.69;1.38]

0.88

1.02 [0.70;1.49]

0.90

0.98 [0.69;1.40]

0.91

SB duration (min) ^g

27.5

(16.8–40.8)

25.8

(18.0-40.5)

0.72 [0.45;1.17]

0.19

0.78 [0.47;1.27]

0.32

0.77 [0.47;1.28]

0.32

0.78 [0.47;1.28]

0.32

NREM SB duration (min) ^b

3.8

(2.5–7.4)

5.0

(3.0–7.0)

0.85 [0.53;1.39]

0.52

0.80 [0.50;1.30]

0.38

0.84 [0.51;1.39]

0.49

0.79 [0.49;1.29]

0.35

REM SB duration (min) ^b

0.5

(0.0–4.0)

0.0

(0.0-4.5)

0.92 [0.65;1.29]

0.62

0.95 [0.68;1.34]

0.79

0.95 [0.66;1.36]

0.77

0.96 [0.68;1.35]

0.81

Sleep efficiency (%) ^d

66.7

(59.5–75.5)

70.2

(63.8–78.6)

1.39 [0.93;2.08]

0.11

1.38 [0.92;2.06]

0.12

1.42 [0.93;2.16]

0.10

1.43 [0.94;2.18]

0.10

Sleep latency (min) ^c

86.5

(64.0-133.8)

84.5

(68.0-143.5)

1.17 [0.76;1.79]

0.47

1.21 [0.77;1.88]

0.41

1.32 [0.85;2.07]

0.22

1.21 [0.78;1.89]

0.40

WASO (min) ^c

180.3

(130.5-226.8)

158.5

(121.0-202.5)

0.70 [0.47;1.06]

0.09

0.71 [0.47;1.07]

0.10

0.69 [0.45;1.05]

0.08

0.68 [0.44;1.05]

0.08

AHI (/h) ^d

4.3

(1.6–11.9)

4.0

(0.2–10.5)

1.01 [0.66;1.53]

0.98

0.97 [0.64;1.46]

0.87

1.04 [0.69;1.58]

0.84

0.96 [0.63;1.45]

0.84

iPLMS ^e

23.3

(10.4–37.6)

15.7

(6.8–46.0)

1.12 [0.69;1.83]

0.65

1.21 [0.73;2.00]

0.46

1.09 [0.65;1.82]

0.74

1.19 [0.72;1.98]

0.49

O2 desaturation index > 3% ^d

7.0

(4.0–15.0)

8.0

(4.0–14.0)

0.95 [0.60;1.52]

0.84

1.02 [0.62;1.68]

0.94

1.13 [0.69;1.84]

0.63

1.01 [0.61;1.68]

0.96