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September 1986

Neocortical Metabolic Abnormalities Precede Nonmemory Cognitive Defects in Early Alzheimer's-Type Dementia

Author Affiliations

From the Section on Brain Aging and Dementia, Laboratory of Neurosciences, National Institute on Aging, Bethesda, Md.

Arch Neurol. 1986;43(9):882-885. doi:10.1001/archneur.1986.00520090022010

• Neuropsychological function and resting regional neocortical glucose metabolism, as measured by positronemission tomography, were studied in 22 patients with mild and moderate Alzheimer's-type dementia. Metabolic reductions in the parietal association cortex and increased left-right metabolic asymmetry were observed in patients with mild and moderate degrees of dementia. Five patients with mild dementia had no impairment of neocortically mediated neuropsychological function, yet they demonstrated these same neocortical metabolic abnormalities. Asymmetry of neocortically mediated, neuropsychological functions correlated with metabolic asymmetries in patients with moderate but not mild dementia. These results suggest that physiological dysfunction in the association neocortex is evident in early Alzheimer's-type dementia before the neuropsychological consequences of that dysfunction are demonstrable.