Longer time between MRIs correlated with greater volume declines in several cortical gray matter ROIs: lateral frontal (r=−.44, p=.0202), precuneus (r=−.62, p=.0004), and parietal (r=−.43, p=.0239) volumes. Using multiple regression, we attempted to discern whether these relations were attributable to length of interval or to age at MRI 1 and found that interval length made an independent contribution to the volume changes (p=.0235 for lateral frontal, p=.0004 for precuneus, and p=.0264 for parietal volumes) over and above the contribution from age.
