Cognitive dysfunction in patients with very mild Alzheimer's disease and amnestic mild cognitive impairment showing hemispheric asymmetries of hypometabolism on ¹⁸F-FDG PET.

Objective We investigated cognitive dysfunction in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) who present hemispheric asymmetries of cerebral metabolic rate of glucose (CMRglc) decrease on 18F-fluorodeoxyglucose positron emission tomography. Methods Based on the hemispheric asymmetries of CMRglc decrease in the posterior cingulate cortex, precuneus, and parietotemporal cortex, the patients were divided into three groups (a left-dominant hypometabolism group, a right-dominant hypometabolism group, and a non-dominant hypometabolism group). CMRglc decrease in the whole brain was controlled among the three groups. All the patients underwent mini-mental state examination (MMSE), Wechsler Memory Scale-Revised (WMS-R), and Wechsler Adult Intelligent Scale-Third (WAIS-III). Results There were no significant differences in MMSE and WAIS-III scores among the three groups. In WMS-R, the results indicated that the left-dominant group demonstrated significantly lower scores in verbal memory than the other two groups. Furthermore, the left-dominant group had a greater tendency to be diagnosed with AD rather than aMCI. Conclusions Patients with AD and aMCI showing left-dominant hypometabolism tend to show severer impairment in verbal memory function and to be diagnosed with AD dementia. Copyright © 2015 John Wiley & Sons, Ltd.