Differences in cerebral glucose metabolism between early-and late-onset of Alzheimer's disease

Objective To investigate the differences in the cerebral glucose metabolism between early-and late-onset of Alzheimer's disease(AD),using a voxel-based method.Methods Nine early-onset and 14 late-onset AD patients were included in our study.Two groups of age-matched normal subjects were used as normal controls.~(18)SF-fluorodeoxyglucose(FDG)PET imaging was performed in all subjects to evaluate the relative cerebral glucose metabolic rate.Subsequently,PET data was statistically compared between the patients and the normal controls using statistical parametric mapping.Results As compared with the age-matched normal controls,respectively,significant hypometabolic regions were found bilaterally in the superior frontal gyrus(BA6,8),middle frontal gyrus(BA6),left inferior parietal lobule(BA39), right supramarginal gyrus(BA40)and the posterior cingulate cortex(BA31)in early-onset AD patients (P0.01)and bilaterally in the superior frontal gyms(BA8),middle frontal gyrus(BA6,8),precuneus (BA19)and right angular gyrus(BA39)in late-onset AD patients(P0.01).Conclusions The early- onset patients are involved in wider areas with a severer degree of metabolic deterioration than the late-onset group as compared with the age-matched normal controls,respectively,though their dementia severity, duration of the illness and the level of education are all similar.The hypothesis of cognitive reserve capability may account for the differences in the cerebral glucose metabolism between the early-onset and the late-onset types of AD.