The distribution of amyloid plaques in the cerebellum and brain stem in Down's syndrome and Alzheimer's disease: a light microscopical analysis.

The distribution and severity of the neuropathological changes in 57 cases of Alzheimer's disease, and 11 patients with Down's syndrome were investigated with reference to the cerebellum. A modified silver stain and a monoclonal antibody raised against amyloid beta-protein were used to identify amyloid plaques. The highest incidence of amyloid plaques in the cerebellum (93%) was found in the group of patients who developed dementia before 65 years of age. This figure dropped to 56% in those patients with dementia beginning after 75 years. In 37 of these cases the distribution of the pathological changes of the disease were also examined in the brain stem. The severity of the pathological changes in the cerebellum corresponded to the involvement of the brain stem nuclei with connections to the cerebellar cortex. The possibility that the disease process spreads to the cerebellum by involving the fibres from the brain stem is discussed with reference to previous anatomical and neurochemical studies.