AMYLOID BETA-PEPTIDE AND ITS RELATIONSHIP WITH DEMENTIA IN LEWY BODY DISEASE

Cerebral cortical Lewy bodies occur in a spectrum of clinical syndrome s including Parkinson's disease (PD) with and without dementia, and de menting conditions clinically resembling Alzheimer's disease with few or without parkinsonian features. It is unclear whether these conditio ns are variants of one disease process or represent pathogenetically d istinct entities. Here we compared the cortical pathology in post mort em brains of three groups representing the predominant clinical phenot ypes of Lewy body disease, including 27 non-demented cases of PD, 23 d emented FD cases, and 11 cases of Lewy body disease who initially pres ented with dementia and showed only limited features of parkinsonism d uring the course of their illness. In addition to neuropathology, comp uter-assisted histoblot analysis was used to assess cortical amyloid b eta-peptide deposition. There was wide overlap of the pathomorphometri c features between the two groups of demented cases. It appears that s ubstantial cortical Alzheimer-type pathology present in most demented cases contributes significantly to the development of dementia in Lewy body disease.