Dementia and neuropathology in Lewy body disease.

In order to elucidate the pathological differences between demented and nondemented patients with Lewy body disease, brains from 35 patients were clinicopathologically examined. In diffuse Lewy body disease, cortical lesions, including numerous Lewy bodies and senile changes, were found to be responsible for the dementia. In some of the cases with the brain-stem type of Lewy body disease, the dementia was attributed to an Alzheimer pathology, while in many cases the various combinations of degeneration in the subcortical nuclei, mainly the nucleus basalis of Meynert and locus ceruleus, played a major role in the dementia. Forty-four Japanese cases with diffuse Lewy body disease were reviewed. Then diffuse Lewy body disease was divided into two forms: a common form (33 cases) and a pure form (11 cases). In the common form, all cases showed progressive cortical dementia in the presenile or senile period. Parkinson syndrome was usually marked in the terminal stage. However, about a fifth of the cases had no parkinsonism. Neuropathologically, the common form had many concomitant senile changes in the cerebral cortex. Most cases with the pure form showed juvenile Parkinson syndrome followed by progressive cortical dementia, while a few cases were of presenile or senile occurrence. Neuropathologically, the pure form had no or few senile changes. This suggests that numerous cortical Lewy bodies alone can cause cortical dementia.