title: Brain perfusion correlates of visuoperceptual deficits in mild cognitive impairment and mild Alzheimer's disease.
abstract: Visuoperceptual processing is impaired early in the clinical course of Alzheimer's disease (AD). The 15-Objects Test (15-OT) detects such subtle performance deficits in mild cognitive impairment (MCI) and mild AD. Reduced brain perfusion in the temporal, parietal, and prefrontal regions have been found in early AD and MCI patients. The objectives of this study were to confirm the role of the 15-OT in the diagnosis of MCI and AD and to investigate the brain perfusion correlates of visuoperceptual dysfunction (15-OT) in subjects with MCI, AD, and normal aging. Forty-two AD, 42 MCI, and 42 healthy elderly control subjects underwent a brain Single Photon Emission Tomography (SPECT) and separately completed the 15-OT. An analysis of variance compared 15-OT scores between groups. SPM5 was used to analyse the SPECT data. 15-OT performance was impaired in the MCI and AD patients. In terms of the SPECT scans, AD patients showed reduced perfusion in temporal-parietal regions, while the MCI subjects had decreased perfusion in the middle and posterior cingulate. When MCI and AD groups were compared, a significant brain perfusion reduction was found in temporo-parietal regions. In the whole sample, 15-OT performance was significantly correlated with the clinical dementia rating scores, and with the perfusion in the bilateral posterior cingulate and the right temporal pole, with no significant correlation in each separate group. Our findings suggest that the 15-OT performance provides a useful gradation of impairment from normal aging to AD, and it seems to be related to perfusion in the bilateral posterior cingulate and the right temporal pole.
authors.affiliation: Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain. malegret@fundacioace.com
authors.forename: Montserrat
authors.initials: M
authors.lastname: Alegret
authors.forename: Georgina
authors.initials: G
authors.lastname: Vinyes-Junqué
authors.forename: Mercè
authors.initials: M
authors.lastname: Boada
authors.forename: Pablo
authors.initials: P
authors.lastname: Martínez-Lage
authors.forename: Gemma
authors.initials: G
authors.lastname: Cuberas
authors.forename: Ana
authors.initials: A
authors.lastname: Espinosa
authors.forename: Isabel
authors.initials: I
authors.lastname: Roca
authors.forename: Isabel
authors.initials: I
authors.lastname: Hernández
authors.forename: Sergi
authors.initials: S
authors.lastname: Valero
authors.forename: Maitée
authors.initials: M
authors.lastname: Rosende-Roca
authors.forename: Ana
authors.initials: A
authors.lastname: Mauleón
authors.forename: James T
authors.initials: JT
authors.lastname: Becker And
authors.forename: Lluís
authors.initials: L
authors.lastname: Tárraga
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006179:Gyrus Cinguli / Q000098:blood supply / Q000000981:diagnostic imaging / Q000502:physiology; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon; D014796:Visual Perception / Q000502:physiology*