June 1989

Cerebral Glucose Metabolic Patterns in Alzheimer's DiseaseEffect of Gender and Age at Dementia Onset

Author Affiliations

From the Departments of Psychiatry and Biobehavioral Sciences (Drs Small and Riege), Neurology (Drs Fujikawa, Metter, and Mazziotta), and Radiological Sciences (Dr Mazziotta), UCLA School of Medicine; the Division of Nuclear Medicine, University of Michigan School of Medicine, Ann Arbor (Dr Kuhl); and the Department of Psychiatry, Southern Illinois University School of Medicine, Springfield (Dr Ashford).

Arch Gen Psychiatry. 1989;46(6):527-532. doi:10.1001/archpsyc.1989.01810060047008

• No previous study of Alzheimer's disease has, to our knowledge, assessed the effect of both age at dementia onset and gender on cerebral glucose metabolic patterns. To this end, we used positron emission tomography (fludeoxyglucose F 18 method) to study 24 patients with clinical diagnoses of probable Alzheimer's disease. Comparisons of the 13 patients with earlyonset dementia (<65 years of age) with the 11 patients with lateonset dementia (>65 years of age) revealed significantly lower left parietal metabolic ratios (left posterior parietal region divided by the hemispheric average) in the early-onset group. The metabolic ratio of posterior parietal cortex divided by the relatively disease-stable average of caudate and thalamus also separated patients with early-onset dementia from those with late-onset dementia, but not men from women. Further comparisons between sexes showed that, in all brain regions studied, the 9 postmenopausal women had higher nonweighted mean metabolic rates than the 15 men from the same age group, with hemispheric sex differences of 9% on the right and 7% on the left. These results demonstrate decreased parietal ratios in earlyonset dementia of Alzheimer's disease, independent of a gender effect.