Metabolic reduction in the posterior cingulate cortex in very early Alzheimer's disease

Authors

  • Saroshi Minoshima PhD., MD,

    Corresponding author
    1. Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI
    • Division of Nuclear Medicine, Department of Internal Medicine, The University of Michigan, BlG412 University Hospital, Ann Arbor, MI 48109-0028
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  • Bruno Giordani PhD.,

    1. Department of Psychiátry, The University of Michigan Medical School, Ann Arbor, MI
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  • Stanley Berent PhD.,

    1. Department of Psychiátry, The University of Michigan Medical School, Ann Arbor, MI
    2. Department of Neurology, The University of Michigan Medical School, Ann Arbor, MI
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  • Kirk A. Frey PhD., MD,

    1. Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI
    2. Department of Neurology, The University of Michigan Medical School, Ann Arbor, MI
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  • Norman L. Foster MD,

    1. Department of Neurology, The University of Michigan Medical School, Ann Arbor, MI
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  • David E. Kuhl MD

    1. Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI
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Abstract

This study investigated cerebral glucose metabolism in very early Alzheimer's disease, before a clinical diagnosis of probable Alzheimer's disease is possible, using [18F]fluorodeoxyglucose positron emission tomography. First, 66 patients with probable Alzheimer's disease with a spectrum of dementia severity (Mini-Mental State Examination score, 0–23) were recruited and studied. Cortical metabolic activity was analyzed topographically using three-dimensional stereotactic surface projections. Regression analysis was performed for each brain pixel to predict metabolic patterns of very early disease. Predictions were tested prospectively in a group of 8 patients who complained only of memory impairment without general cognitive decline (Mini-Mental State Examination score, 25 · 1) at the time of scanning but whose condition later progressed to probable Alzheimer's disease. Both results were compared to cerebral metabolic activity in 22 age-similar normal control subjects. Prediction and analysis of actual patients consistently indicated marked metabolic reduction (21–22%) in the posterior cingulate cortex and cinguloparietal transitional area in patients with very early Alzheimer's disease. Mean metabolic reduction in the posterior cingulate cortex was significantly greater than that in the lateral neocortices or parahippocampal cortex. The result suggests a functional importance for the posterior cingulate cortex in impairment of learning and memory, which is a feature of very early Alzheimer's disease.

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