REDUCTION OF CEREBELLAR GLUCOSE-METABOLISM IN ADVANCED ALZHEIMERS-DISEASE

Although regional cerebral metabolism and blood flow in Alzheimer's di sease (AD) have been studied extensively with PET and SPECT, few repor ts have been concerned with cerebellar metabolism or perfusion in Alzh eimer's disease. To evaluate cerebellar glucose metabolism in Alzheime r's disease patients, we studied the cerebellar and cerebral metabolic rate for glucose (CMRglc) using 2[F-18]fluoro-2-deoxy-D-glucose (F-18 -FDG) and PET. Methods: Sixty-eight patients with Alzheimer's disease and 13 age-matched normal control subjects were examined. According to scores obtained on the Mini-Mental State Examination (MMSE), Alzheime r's disease patients were classified into three groups: severe (n = 9) , moderate (n = 33) and mild (n = 26). Results: The cerebellar glucose metabolism in the severe Alzheimer's disease group was significantly lower (cerebellar glucose metabolism: 5.71 +/- 0.62 mg/100 g/min) than that of the control group (6.85 +/- 0.66 mg/100 g/min), while tempora l and parietal CMRglc were much more decreased. The cerebellar glucose metabolism in the mild and moderate Alzheimer's disease groups also s howed lower revels than that of the control group, but the differences did not reach significant levels. Like other cortical CMRglc, the cer ebellar glucose metabolism correlated with cognitive impairments. Conc lusion: In severe Alzheimer's disease, cerebellar glucose metabolism i s significantly reduced. The method of analysis using normalization of regional metabolic data to cerebellar values may be liable to err in severe Alzheimer's disease patients.