Diffuse Lewy body disease and progressive dementia.

Thirty cases of diffuse Lewy body disease (DLBD) have been reported, primarily by neuropathologists, but an associated clinical syndrome has not been clearly defined. Four recent cases have led us to examine the clinicopathologic correlations. Patients are usually elderly, with symptoms lasting from 1 to 20 years. Progressive dementia or psychosis is typically the first and most prominent feature. Parkinsonian signs, initially mild or absent, become common eventually, and rigidity is usually severe. Involuntary movements, myoclonus, quadriparesis in flexion, orthostatic hypotension, and dysphagia have also been noted. Classic, concentric Lewy bodies are found profusely in the brainstem, basal forebrain, and hypothalamic nuclei, while less well defined "Lewy-like" bodies occur in limbic structures and in deep neocortical layers. In addition, focal spongiform changes in the mesial temporal lobe were found in two of our cases. We suggest that DLBD may be another specific cause of progressive dementia.