Table 1.

Comparisons of mean (SD) diffusion tensor–derived parameters in elderly and young subject groups

Region of interestElderly (n = 19)Young (n = 10)p Valuep Value*
p Values are shown before (p) and after (p*) covarying for sex and white matter volume (atrophy).
FA = fractional anisotropy.
Total white matter
    Volume, cm3357 (38)393 (35)0.0210.008
    FA0.225 (0.012)0.238 (0.007)0.0010.028
    Diffusivity, 10−6mm2 · S−1912 (58)814 (23)<0.001<0.001
Anterior white matter
    Volume, cm3100 (15)112 (17)0.0740.049
    FA0.199 (0.012)0.221 (0.007)<0.001<0.001
    Diffusivity, 10−6mm2 · S−1942 (64)830 (27)<0.001<0.001
Middle white matter
    Volume, cm3104 (20)114 (22)0.240.194
    FA0.256 (0.019)0.272 (0.015)0.0160.067
    Diffusivity, 10−6mm2 · S−1881 (65)786 (17)<0.001<0.001
Posterior white matter
    Volume, cm3159 (25)174 (17)0.0670.052
    FA0.234 (0.013)0.239 (0.012)0.2670.510
    Diffusivity, 10−6mm2 · S−1896 (50)824 (24)<0.0010.002