title: Anatomical and functional alterations in semantic dementia: a voxel-based MRI and PET study.
abstract: Rare studies have used magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) to assess atrophy, and only two positron emission tomography (PET) studies used SPM to examine functional changes in semantic dementia (SD). Our aim was to highlight both morphological and functional abnormalities in a same group of 10 SD patients, in the entire brain, using a "state of the art" methodology (optimized VBM procedure, PET data corrected for partial volume effects and voxel-based analyses). We also used an extensive neuropsychological battery. We showed that main alterations concerned the left temporal lobe, in accordance with the striking impairment of semantic memory in SD patients, as well as the hippocampal region, which may partly explain their moderate episodic memory deficits. Hypometabolism was more extensive than grey matter loss in both temporal lobes, and specifically concerned the orbitofrontal areas, consistent with the moderate impairment of executive functions and behavioural changes. While PET is more sensitive than MRI, there is striking concordance between morphological and functional abnormalities, which contrasts with the discordance observed in Alzheimer's disease and might be a typical feature of SD.
authors.affiliation: Inserm-EPHE-Université de Caen, Unité E0218, GIP Cyceron, CHU de Caen, Caen, France. desgranges-b@chu-caen.fr
authors.forename: Béatrice
authors.initials: B
authors.lastname: Desgranges
authors.forename: Vanessa
authors.initials: V
authors.lastname: Matuszewski
authors.forename: Pascale
authors.initials: P
authors.lastname: Piolino
authors.forename: Gaël
authors.initials: G
authors.lastname: Chételat
authors.forename: Florence
authors.initials: F
authors.lastname: Mézenge
authors.forename: Brigitte
authors.initials: B
authors.lastname: Landeau
authors.forename: Vincent
authors.initials: V
authors.lastname: de la Sayette
authors.forename: Serge
authors.initials: S
authors.lastname: Belliard
authors.forename: Francis
authors.initials: F
authors.lastname: Eustache
mesh_terms: D000222:Adaptation, Physiological; D000368:Aged; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D003704:Dementia / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*