Table 2.

Comparisons of baseline EEG characteristics between ED+ and ED- groups.

	ED- (n = 59)	ED+ (n = 51)	All (n = 110)	T-tests, degrees of freedom	Value of p	Effect size
EEG-vigilance stages (%)
Stage 0	14.7 ± 16.2	17.7 ± 22.0	16.1 ± 19.1	−0.80, 108	0.424	d = 0.15
Stage A	54.2 ± 30.0	47.4 ± 31.9	51.0 ± 30.9	1.17, 108	0.245	d = 0.23
Stage A1	45.4 ± 31.3	41.5 ± 31.3	43.6 ± 31.3	0.66, 108	0.510	d = 0.13
Stage A2	5.4 ± 9.0	4.7 ± 6.8	5.1 ± 8.0	0.44, 108	0.658	d = 0.09
Stage A3	3.4 ± 8.7	1.2 ± 1.9	2.4 ± 6.6	1.93, 64.6	0.058	g = 0.34
Stage B1	14.4 ± 17.3	16.5 ± 21.5	15.4 ± 19.3	−0.58, 108	0.566	d = 0.11
Stage B2/3	8.9 ± 15.8	12.7 ± 14.7	10.7 ± 15.3	−1.29, 108	0.199	d = 0.25
Stage C	7.7 ± 14.4	5.8 ± 9.7	6.8 ± 12.4	0.82, 108	0.414	d = 0.16
Mean EEG-vigilance level	4.9 ± 1.2	4.8 ± 1.3	4.8 ± 1.3	0.15, 108	0.882	d = 0.03
Arousal stability score	6.1 ± 3.8	6.2 ± 3.8	6.1 ± 3.8	0.15, 108	0.918	d = 0.02

Entries are mean ± standard deviation or numbers (%).

Bold fonts indicate statistical significance; the statistical significance value for these tests was set at 0.05.

d indicates effect sizes were estimated by Cohen’s d.

g indicates effect sizes were estimated by Hedge’s g in case of unequal group variance using the pooled standard variance.