Clinicopathological analysis of dementia disorders in the elderly--an update

Abstract

A retrospective clinico-pathological study of a consecutive autopsy series of 1050 elderly demented individuals (mean age 83.4 +/- 6.0 years; MMSE < 20) was performed. Clinical diagnoses were probable or possible Alzheimer disease (62.9%), nonspecific degenerative dementia (10.4%), vascular dementia (10%), Parkinson disease with dementia (9.5%), 1.5% mixed dementia, and 5.7% other disorders. At autopsy, 86% revealed Alzheimer-related pathology, but only 42.8% showed "pure" Alzheimer disease, with additional cerebrovascular lesions in 22.6% and Lewy body pathology in 10.8%, while among 660 cases of clinically suspected Alzheimer disease, Alzheimer pathology was seen in 93%, only 44.7% in "pure" form, and additional vascular lesions and Lewy bodies in 27.7 and 10%, respectively. The non-Alzheimer cases included Huntington and Creutzfeldt-Jakob disease, frontotemporal dementias, and others. These and other recent data indicate that in patients with the clinical diagnosis of Alzheimer disease its combination with cerebrovascular lesions and Lewy body pathologies is rather frequent. Comparison of clinical and postmortem diagnoses revealed postmortem confirmation of Alzheimer disease in 93%, of mixed and vascular dementia in 60 and 52.3%, respectively. 78% of clinically suspected degenerative dementias were pathologically definite Alzheimer disease, while in the clinical Parkinson + dementia group dementia with Lewy bodies accounted for 35%, Parkinson+Alzheimer disease, and "pure" Alzheimer disease for 29%, each. A sample of 207 prospectively studied elderly showed significant negative correlation between the preterminal psychostatus assessed by MMSE and the neuritic Braak stages, with a broad "gray" zone of Alzheimer lesions in mildly to moderately demented subjects. Similar relations between CDR and Braak stages were seen in very old subjects. The present study and the results of other recent series indicate increasing agreement between clinical and autopsy diagnoses in demented aged individuals with variable accuracy rates for different forms of dementia disorders.