title: Metabolic correlates of clinical heterogeneity in questionable Alzheimer's disease.
abstract: Thirty-four subjects with questionable Alzheimer's disease (QAD) were included in a 3-year prospective study and underwent neuropsychological testing and measurement of brain metabolism using FDG-PET at entry. Seventeen patients (50%) did not convert to AD during the follow-up period. Compared to elderly controls of similar age, the cerebral activity of non-converters was reduced in the dorsolateral prefrontal cortex. Moreover, the variability of metabolism in the posterior cingulate cortex was related to their visuospatial memory performance, while disparity in parietal activity was related to their verbal memory performance. These results demonstrate the cerebral metabolic heterogeneity of patients with QAD. Initial functional images of converters showed that activity was already impaired in the posterior cingulate, lateral temporal cortex, anterior cingulate and orbitofrontal cortex. This metabolic pattern is consistent with a pre-dementia stage of AD, and highlights the fact that significant frontal metabolic involvement may be associated with impaired activity in posterior associative cortices in very early AD.
authors.affiliation: Department of Neurology, CHU Liège, 4000 Liège, Belgium. eric.salmon@ulg.ac.be
authors.forename: Eric
authors.initials: E
authors.lastname: Salmon
authors.forename: Françoise
authors.initials: F
authors.lastname: Lekeu
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Garraux
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Guillaume
authors.forename: Delphine
authors.initials: D
authors.lastname: Magis
authors.forename: A
authors.initials: A
authors.lastname: Luxen
authors.forename: G
authors.initials: G
authors.lastname: Moonen
authors.forename: F
authors.initials: F
authors.lastname: Collette
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000378:metabolism*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18