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. Author manuscript; available in PMC: 2018 Mar 9.
Published in final edited form as: Brain Imaging Behav. 2017 Dec;11(6):1720–1730. doi: 10.1007/s11682-016-9647-x

Table 2.

Characteristics of the NACC subsample used for the correlation analyses (total WMH volume ≥ 13.5 ml). Numbers are given as mean ± standard deviation [range] (deviant sample size).

Characteristic AD (n = 29) VaD (n = 33) NC (n = 18) all (n = 80) p-value* (ANOVA)
Age [years] 80.86 ± 6.15 83.92 ± 5.46 82.98 ± 4.30 82.60 ± 5.60 .094
Sex [females] 13 / 44.8 % 18 / 54.5 % 12 / 66.7 % 43 / 53.8 % .342
Education [years] 14.62 ± 2.83 14.09 ± 3.69 16.17 ± 2.38 14.75 ± 3.20 .081
CERAD-plus [z-scores]
 Animals −1.61 ± 0.75 −1.23 ± 0.82 −0.25 ± 0.61 −1.15 ± 0.90 .000b,c
 Boston −2.90 ± 2.10 −2.15 ± 1.61 (n = 31) −0.34 ± 0.78 −2.01 ± 1.92 (n = 78) .000b,c
 MMSE −5.88 ± 3.05 −3.78 ± 3.57 (n = 32) 0.42 ± 1.08 −3.59 ± 3.78 (n = 79) .000a,b,c
 TMT-A −1.89 ± 2.94 −2.41 ± 2.98 (n = 29) 0.20 ± 0.80 −1.59 ± 2.78 (n = 76) .004b,c
 TMT-B −3.41 ± 1.60 (n = 28) −2.38 ± 1.59 (n = 25) −0.18 ± 0.84 −2.23 ± 1.92 (n = 71) .000b,c
WMH
 Total volume [ml] 29.77 ± 14.63 [14.30–69.87] 32.63 ± 15.55 [13.74–74.37] 27.89 ± 11.24 [13.63–49.09] 30.53 ± 14.30 [13.63–74.37] .502
 COSU 11.20 ± 2.85 [7.74 ± 17.93] 9.41 ± 2.89 [4.71–17.54] 9.08 ± 2.29 [6.22–13.44] 9.98 ± 2.87 [4.71–17.93] .014a,b

AD Alzheimer’s disease, COSU confluency sum score, MMSE mini-mental state examination, NC normal control, TMT trail making test, VaD vascular dementia, WMH white matter hyperintensities

a

Post-hoc analysis: significant group difference between ‘AD’ and ‘VaD’

b

Post-hoc analysis: significant group difference between ‘AD’ and ‘NC’

c

Post-hoc analysis: significant group difference between ‘VaD’ and ‘NC’

*

Comparison of numerical characteristics (all except sex) between the three groups was performed by one-way ANOVA. In case of a significant between groups effect, post hoc multiple comparisons were performed using either Scheffe’s test (assuming equal variance) or Tamhane’s test (unequal variance), depending on the result of Levene’s test for homogeneity of variance. The chi-square test was used to compare the distribution of sex between the three groups. In case of a significant between groups effect, the chi square test was applied to all possible pairs of two groups. A significance level of α = 0.05 was assumed for between all groups tests as well as for post hoc tests