Heterogeneity of Brain Glucose Metabolism in Mild Cognitive Impairment and Clinical Progression to Alzheimer Disease

Abstract

Mild cognitive impairment (MCI) is a diagnostic entity used to describe defective memory performances that do not fulfill the criteria for dementia.¹ Mild cognitive impairment includes incipient Alzheimer disease (AD) and other causes of dementia, as well as a form of cognitive impairment that does not progress to dementia and may disappear. This entity has been redefined to include amnesic MCI (aMCI) and nonamnesic MCI, according to the presence of an isolated objective memory deficit or of multiple or isolated extramemory cognitive impairment.² This variation in MCI has been evaluated using neuroimaging^3-5 and biologic markers.^6,7 Results of clinical studies^5,8 have suggested that neuropsychological tests, especially those evaluating delayed recall, might play an important role in identifying early or preclinical AD among subjects with MCI. These studies, however, were conducted among small groups of subjects.