TABLE 1.

Demographical and neuropsychological performance data of all participants (mean ± standard derivation).

	Poor sleepers (PS)		Good sleepers (GS)		p-value
	Male	Female	Male	Female	Sleep quality	Gender	Sleep quality × Gender
Number of participants	57	62	77	43	0.011*	NA	NA
Age (years)	65.88 (6.13)	65.10 (5.24)	65.99 (5.51)	64.72 (5.59)	0.85	0.17	0.74
Education (years)	9.89 (1.93)	9.71 (1.81)	10.01 (2.14)	9.74 (1.85)	0.65	0.30	0.99
Pittsburgh Sleep Quality Index (PSQI)	11.56 (1.44)	12.42 (2.01)	5.09 (0.88)	5.02 (0.80)	NA	0.032*	NA
Beck Depression Inventory (BDI)	7.20 (5.91)	6.77 (3.8)	3.84 (2.51)	5.65 (3.77)	<0.001*	0.20	0.039*
Habitual intake of coffee (cups)	4.76 (0.74)	4.47 (1.03)	4.86 (0.64)	4.36 (1.28)	0.98	0.003*	0.42
Physical activity (hours/week)	3.53 (2.68)	3.13 (2.63)	4.43 (5.73)	5.07 (4.44)	0.005*	0.98	0.24
Body Mass Index (BMI)	26.46 (3.71)	28.61 (5.54)	27.27 (5.76)	25.88 (4.29)	0.84	0.27	0.31
Total Intracranial Volume (mm3)	1,556,080 (111,287)	1,375,386 (87,567)	1,390,511 (83,202)	15,658,825 (111,360)	0.35	<0.001*	0.84
Current stress levels (Kurzfragebogen zur aktuellen Beanspruchung, KAB1)	26.75 (6.09)	28.61 (5.88)	23.81 (5.94)	26.47 (5.97)	0.001*	0.005*	0.61
Current stress levels (Kurzfragebogen zur aktuellen Beanspruchung, KAB2)	26.44 (5.63)	28.90 (6.58)	23.30 (5.74)	25.98 (5.71)	<0.001*	0.001*	0.89
Trail Making Test (part A, TMT-A)	39.22 (12.52)	42.26 (16.09)	39.02 (12.38)	38.32 (11.98)	0.24	0.51	0.29
Selective attention task (Alters-Konzentrations-Test, AKT)	34.08 (10.22)	34.56 (8.26)	32.62 (7.79)	35.03 (9.09)	0.67	0.21	0.41
Visual pattern (VPT, Juelich version)	8.18 (1.76)	6.77 (1.43)	8.40 (1.73)	6.88 (1.61)	0.44	<0.001*	0.79
Verbal working memory (Zahlennachsprechen, ZNS)	11 (2.05)	10.63 (1.59)	10.71 (1.70)	10.42 (1.72)	0.29	0.16	0.87
Corsi Block-Tapping-Test (CBT)	10.33 (1.66)	9.85 (1.35)	10.56 (1.72)	10.12 (1.48)	0.24	0.03*	0.93

Abbreviations: NA, not applicable. *Significant level at p < 0.05 level.