Pathological markers associated with normal aging and dementia in the elderly.

We investigated the associations of pathological markers of Alzheimer's disease (AD) and diffuse Lewy body disease as well as possible markers of vascular dementia with cognitive function in a sample of 20 nondemented and 35 demented subjects (median age of both groups, 88 years) who had been studied prospectively for 4.0 +/- 2.1 years. Very old demented subjects almost always had nonneuritic senile plaques, but over half had no neuritic senile plaques and little other AD pathology. Five subjects had cortical Lewy bodies; all were demented. We propose that hippocampal sclerosis, leukoencephalopathy, and multiple lacunae are possible markers of vascular dementia. When grouped together, these markers were significantly associated with dementia and occurred in 40% of demented subjects. As the relative frequency of neuritic markers of AD (and possibly AD itself) declines in the tenth decade, vascular dementia may become an increasingly important type of dementia.