CPAP Treatment Partly Normalizes Sleep Spindle Features in Obstructive Sleep Apnea
Table 2
Median and range of the spindle features in the study groups in the first part of the NREM time.
Controls
Pre-CPAP
CPAP
Controls versus pre-CPAP
Controls versus CPAP
Pre-CPAP versus CPAP
Median
Range
Median
Range
Median
Range
value
value
value
Density /h
Bil Fp dens
33.7
3.4–94.8
22.5
0.3–117.7
23.7
0.0–0.0
0.671
1.0
1.0
Fp2 dens
77.5
14.6–138.6
48.2
8.8–183.9
50.8
0.0–0.0
1.0
1.0
1.0
Fp1 dens
68.0
15.0–129.0
49.0
6.9–143.0
50.9
0.0–0.0
0.912
1.0
1.0
Bil C dens
55.9
11.8–161.2
29.1
1.0–215.7
27.8
1.4–202.8
0.250
0.361
1.0
C4 dens
104.7
36.4–194.2
58.3
13.7–194.3
79.6
16.5–181.5
0.369
1.0
0.741
C3 dens
116.7
50.2–219.6
56.3
17.3–216.3
85.3
29.0–221.5
0.085
0.224
0.574
Frequency Hz
Bil Fp2 freq
11.8
10.9–12.5
11.5
10.9–13.1
11.4
10.6–12.9
0.702
0.250
0.068
Bil Fp1 freq
11.8
10.9–12.9
11.5
10.7–13.1
11.5
10.8–12.8
0.874
0.516
1.0
Fp2 freq
11.8
10.9–12.3
11.5
10.8–13.1
11.5
10.8–12.8
1.0
1.0
0.013
Fp 1 freq
11.8
11.0–12.5
11.5
10.9–13.0
11.4
10.9–12.8
0.893
0.272
0.042
Bil C4 freq
12.9
11.2–14.4
13.1
11.0–14.6
12.6
10.7–14.0
1.0
0.703
0.006
Bil C3 freq
12.9
11.1–14.3
13.1
11.3–14.9
12.8
10.9–14.4
0.670
1.0
0.007
C4 freq
12.5
11.2–13.7
12.5
11.0–14.2
11.9
11.0–13.8
1.0
0.283
0.043
C3 freq
12.5
11.1–13.8
12.8
11.3–15.1
11.7
11.0–13.9
1.0
0.207
0.001
Sequences %
Fp sequences
0.0
0.0–0.4
0.0
0.0–1.1
0.0
0.0–0.3
1.0
1.0
0.999
C sequences
0.3
0.0–2.4
0.1
0.0
4.4
0.0–3.1
0.720
0.176
0.224
Bilaterality indices
Fp bil index 1
0.48
0.21–0.98
0.36
0.02–0.81
0.44
0.07–0.68
0.185
0.388
1.0
Fp bil index 2
0.54
0.21–0.89
0.36
0.04–1.18
0.44
0.06–0.95
0.388
0.275
1.0
C bil index 1
0.64
0.20–1.31
0.40
0.03–1.16
0.38
0.08–1.12
0.297
0.085
1.0
C bil index 2
0.50
0.14–1.13
0.35
0.06–1.0
0.33
0.05–0.98
0.611
0.145
1.0
Mann-Whitney test; Wilcoxon test. The Bonferroni corrected values are reported: Bonferroni correction factor = 3. Bil Fp/bil C = bilateral frontopolar/central spindle; bil C4, bil C3 = bilateral right-side and left-side spindles, respectively; Fp2, Fp1, C4, and C3 = unilateral spindles; sequences = percentage of time referred to as TST occupied by periodic frontopolar or central spindles; Fp bil index 1 = number of bil Fp spindles divided by the number of unilat Fp2 spindles (bil Fp/Fp2); Fp bil index 2 = number of bil Fp spindles divided by the number of unilat Fp1 spindles (bil Fp/Fp1); C bil index 1 = number of bil C spindles divided by the number of unilat C4 spindles (bil C/C4); C bil index 2 = number of bil C spindles divided by the number of unilat C3 spindles (bil C/C3).
