Alzheimer's disease and the cerebellum: a morphologic study on neuronal and glial changes

Structural manifestations of Alzheimer's disease (AD) including neuronal loss were investigated in 12 cases of AD and in 10 healthy age-matched controls, with focus on the cerebellum. Linear Purkinje cell (PC) density was measured in the vermis and cerebellar hemispheres. Neurons were also counted in the inferior olivary nucleus. In vermis of the AD cases, the mean PC number was significantly lower (p = 0.019) than in the controls. The neurons in the inferior olive were similarly fewer, though not significantly (p = 0.13). Molecular layer gliosis and atrophy in the vermis was clearly severer in AD than in the controls. Features typical of cerebral Alzheimer encephalopathy (plaques, tangles and microvacuolization) were inconspicious. The structural cerebellar changes in the AD cases were thus neuronal loss, atrophy and gliosis, judged to represent the disease process, and with a main involvement in the vermis. This may be reflected in some of the symptoms and signs seen in AD, signs that are generally overlooked or judged to be of noncerebellar origin.