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Table 4 Polysomnographic results for the thirds of the night

From: Similar polysomnographic pattern in primary insomnia and major depression with objective insomnia: a sign of common pathophysiology?

  Mean (SD) Whole sample (N = 209) Mean (SD) Normative (N = 30) Mean (SD) Insomnia (N = 84) Mean (SD) Depression (N = 95) Median (P25-P75) Normative (N = 30) Median (P25-P75) Insomnia (N = 84) Median (P25-P75) Depression (N = 95) P-value
% REM (p < 0.001) (p < 0.001) (p < 0.001) (p < 0.001)     
 1st third 6.97 ± 6.18 10.07 ± 5.23 6.52 ± 6.06 6.29 ± 6.34 10.14 (7.84–14.42) 5.81 (0.00–9.70) 5.76 (0.00–9.73) <0.001a,b
 2nd third 17.62 ± 9.57 20.68 ± 10.02 17.37 ± 9.83 16.87 ± 9.11 19.67 (14.16–27.14) 17.80 (10.34–22.91) 17.26 (11.46–22.04) 0.242
 3rd third 20.62 ± 10.04 26.57 ± 8.32 20.30 ± 11.02 19.14 ± 9.02 27.17 (22.54–31.59) 19.69 (12.20–27.92) 19.20 (13.69–25.62) 0.001a,b
% Stage1 (p = 0.003) (p < 0.001) (p = 0.037) (p = 0.172)     
 1st third 6.10 ± 3.98 6.02 ± 3.33 6.29 ± 4.40 5.95 ± 3.81 5.07 (3.85–7.41) 5.78 (2.61–9.05) 6.00 (2.90–7.78) 0.971
 2nd third 5.76 ± 5.14 5.45 ± 2.92 5.47 ± 4.17 6.11 ± 6.34 4.90(3.10–7.17) 4.52 (2.26–8.55) 5.07 (2.89–7.43) 0.745
 3rd third 7.25 ± 7.19 7.91 ± 3.94 6.79 ± 4.43 7.45 ± 9.58 6.79 (4.80–10.09) 5.42 (3.81–8.89) 5.41 (3.68–9.20) 0.169
% Stage2 (p < 0.001) (p < 0.001) (p < 0.001) (p < 0.001)     
 1st third 39.04 ± 15.96 47.96 ± 10.26 38.99 ± 16.59 36.26 ± 15.97 50.32 (40.52–53.80) 39.33 (29.70–51.08) 38.94 (25.61–47.69) 0.001a,b
 2nd third 53.13 ± 15.33 61.00 ± 11.03 52.60 ± 13.76 51.12 ± 17.06 62.70 (53.86–70.07) 52.79 (47.07–62.95) 55.27 (42.16–63.73) 0.006a,b
 3rd third 43.48 ± 13.81 50.11 ± 9.72 40.57 ± 13.38 43.96 ± 14.60 49.87 (43.58–56.77) 42.11 (32.52–50.89) 45.38 (34.56–54.61) 0.003a
% SWS (<0.001) (<0.001) (<0.001) (<0.001)     
 1st third 9.96 ± 10.41 20.53 ± 11.34 7.84 ± 8.90 8.50 ± 9.40 19.27 (10.61–29.14) 3.76 (0.26–13.21) 4.67 (0.62–15.36) <0.001a,b
 2nd third 7.82 ± 9.97 7.24 ± 7.89 7.94 ± 10.92 7.89 ± 9.77 3.80 (0.93–10.31) 2.03 (0.00–12.52) 3.79 (0.20–12.04) 0.695
 3rd third 2.22 ± 4.61 2.37 ± 4.68 1.98 ± 4.60 2.39 ± 4.65 0.52 (0.00–1.92) 0 (0.00–1.75) 0.29 (0.00–2.75) 0.294
% WASO (p < 0.001) (p < 0.001) (p < 0.001) (p < 0.001)     
 1st third 37.35 ± 21.33 15.41 ± 7.36 39.11 ± 19.65 42.94 ± 21.48 15.63 (10.09–19.07) 36.59 (27.74–50.01) 38.27 (26.94–55.45) <0.001a,b
 2nd third 15.22 ± 18.32 5.63 ± 4.65 15.51 ± 16.80 17.98 ± 21.21 4.68 (2.81–8.10) 12.11 (4.58–19.59) 9.20 (5.42–23.62) <0.001a,b
 3rd third 26.10 ± 18.39 12.27 ± 9.43 29.96 ± 18.57 27.05 ± 18.48 8.92 (5.24–15.51) 27.07 (18.18–41.55) 23.78 (13.95–37.67) <0.001a,b
         Kruskal-Wallis Test
  1. REM Rapid eye movement sleep, SWS slow-wave sleep, WASO wake after sleep onset
  2. After Bonferroni correction: aNormative vs Insomnia p < 0.05, bNormative vs Depression p < 0.05, cInsomnia vs Depression p < 0.05