Table 1

Cognitive ability scores and MRI measures for baseline and 2 year follow-up data

Mean (SD) z scoresPaired sample t test of data at baseline and follow-up
BaselineFollow-up
Cognitive variables
    Executive function0.076 (.684)0.119 (.697)t = −0.979, p = 0.330
    Working memory0.082 (.844)−0.073 (.810)t = −2.57, p = 0.012
    Information processing speed0.062 (.757)0.010 (.467)t = 0.640, p = 0.524
MRI variables
    Normalised whole brain volume (cm3)1589.11 (75.16)1569.71 (81.71)t = 4.38, p<0.001
    WMH (mm3)9036.68 (11615.26)10817.16 (14584.62)t = −5.03, p<0.001
    MD – Normalised peak height frequency0.19547 (.03144)0.19110 (.03426)t = −9.83, p<0.001
    MD – Peak height intensity0.00074 (.00004)0.00075 (.00004)t = 2.55, p = 0.013
    MD – Skewness5.07 (.989)4.36 (.821)t = −0.486, p<0.001
    MD – Kurtosis34.33 (15.574)28.04 (10.776)t = −3.49, p = 0.001
    MD – Median0.00080 (.00004)0.00082 (.00004)t = 5.73, p<0.001
    FA – Normalised peak height frequency0.03112 (.00386)0.03342 (.00437)t = 3.17, p = 0.002
    FA – Peak height intensity0.22288 (.04020)0.21493 (.03485)t = −5.70, p<0.001
    FA – Skewness0.811 (.153)0.849 (.159)t = 11.70, p<0.001
    FA – Kurtosis0.570 (.417)0.659 (.436)t = 6.51, p<0.001
    FA – Median0.282 (.028)0.275 (.025)t = −7.66, p<0.001
  • Values in bold type indicate statistical significance.

  • MD, mean diffusivity; FA, fractional anisotropy; WMH, white matter hyperintensity.