CEREBRAL GLUCOSE-METABOLISM IN PATIENTS WITH FRONTOTEMPORAL DEMENTIA

Frontotemporal dementia (FTD) is a dementia syndrome characterized by peculiar behavioral changes arising from frontotemporal involvement an d distinct from Alzheimer's disease (AD). The purpose of this study wa s to elucidate the specific patterns in cerebral glucose metabolism in patients with FTD and to compare them with the patterns in patients w ith AD and normal elderly subjects using fluorodeoxyglucose (FDG) and PET. Methods: Twenty-one patients with a clinical diagnosis of FTD [me an age 67.0 +/- 7.0 yr, Mini Mental State Examination (MMSE) score 18. 7 +/- 5.7], 21 age-, sex- and dementia-severity-matched patients with probable AD (mean age 66.9 +/- 7.1 yr, MMSE score 20.2 +/- 5.5) and 21 age- and sex matched normal control subjects (mean age 66.8 +/- 5.7 y r) were studied. The cerebral metabolic rate for glucose (CMRglc) was measured with FDG and PET. Absolute measures of regional CMRglc were c ompared among the three groups. One-way ANOVA and the posthoc Tukey HS D test were used for statistical analyses. Results: In the FTD group, CMRglc was preserved only in the left cerebellum, right sensorimotor a rea and occipital lobes, The CMRglc was significantly lower in the FTD group as opposed to the AD group in the hippocampi, orbital gyri, ant erior temporal lobes, anterior cingulate gyri, basal ganglia, thalami, middle and superior frontal gyri and left inferior frontal gyrus. Con clusion: Although metabolic abnormality in FTD is predominant in the f rontal and anterior temporal lobes and the subcortical structures, it is more widespread than has been previously stressed. These findings d ocument an FTD-specific cerebral involvement and facilitate differenti al diagnosis of degenerative dementias.