Neocortical morphometry, lesion counts, and choline acetyltransferase levels in the age spectrum of Alzheimer's disease.

We studied neocortical morphometry (cortical thickness, neurons, and glia), lesion counts (plaques and tangles), and choline acetyltransferase levels in up to 113 Alzheimer brains and 48 controls. Comparisons between young (under 65) and old (over 70) Alzheimer cases revealed more tangles in the former, but no other statistically significant differences in the measured variables. Differences in these parameters between young Alzheimer cases and young controls were similar to the differences found between old Alzheimer cases and old controls. Linear regression analyses correlating some of these variables with age in Alzheimer's disease, considered together with the effects of normal aging on the same parameters, reveal in Alzheimer's disease a spectrum of graded pathologic severity inversely proportional to age. Nevertheless, even in advanced old age (80 to 100), significant differences persist in these parameters between very elderly Alzheimer brains and controls.