Clinically diagnosed Alzheimer's disease: autopsy results in 150 cases.

One hundred fifty autopsy brains from patients with clinically diagnosed Alzheimer's disease (AD) were examined pathologically. The brains were received consecutively over a 3-year period from numerous sources as part of a research program in which one brain half was frozen for biochemical studies and the other half was fixed in formalin. One hundred thirty-one (87%) of the 150 cases fulfilled histological criteria for AD, with or without additional findings, such as Parkinson's disease or stroke. At least a minimal degree of amyloid angiopathy was found in every brain showing histopathological abnormalities of AD. Twenty-three (18%) of the 131 AD brains had Lewy bodies in neurons of the substantia nigra. Thirteen of the 19 non-AD cases were diagnosed as other neurodegenerative disorders. In only 2 cases was no histological correlate for the patient's dementia found. We conclude that (1) the many physicians who diagnosed these cases did so highly accurately; (2) degenerative changes in the substantia nigra were more common in patients with AD than has been reported for the general aged population; (3) amyloid angiopathy was a constant accompaniment of AD, although its severity varied widely; (4) vascular dementia was rarely clinically misdiagnosed as AD; (5) neuropathological findings were insufficient to account for the clinical syndrome of dementia in less than 2% of cases; (6) the histological criteria established by the National Institutes of Health/American Association of Retired Persons Workshop on the Diagnosis of Alzheimer's Disease worked well in assessing this large series.