SPECT in early- and late-onset Alzheimer's disease

We assessed with SPECT the influence of age of onset in Alzheimer's disease in patients who were matched for severity of disease with early and late onset of the disease. Twenty-six patients, severity-matched according to scores on Mini-Mental State Examination, were compared to nine controls. Comparison of the temporoparietal cerebellar ratio (TPC) revealed a statistically significantly lower ratio in the early-onset group compared to the late-onset group of patients. These results are in agreement with other imaging, structural, and neurochemical studies, supporting the view of heterogeneity of Alzheimer's disease according to age of onset.