title: Visuospatial deficits and hemispheric perfusion asymmetries in posterior cortical atrophy.
abstract: We studied visuospatial performance and obtained brain perfusion scintigraphy in 27 patients with posterior cortical atrophy (PCA) and 24 healthy controls, with two aims: (1) to determine inter-hemispheric perfusion imbalances underlying signs of spatial neglect and (2) to establish the functional substrates of patients' performance on distinct visuospatial tasks (line bisection and target cancellation). Between-groups and correlation analyses were performed on a voxel-wise basis with Statistical Parametric Mapping, and right-to-left hemispheric perfusion ratios were calculated in anatomical regions of interest. Nineteen patients had pathological spatial biases. Compared with controls, patients with signs of left-sided and right-sided neglect presented prominent hypoperfusion in the right and left parietal cortex, respectively. Importantly, hypoperfusion extended to the ipsilateral prefrontal regions. Correlation analyses between task scores and brain perfusion showed that shifts in line bisection correlated with hypoperfusion in parieto-frontal regions, whereas omissions on target cancellation mainly correlated with hypoperfusion in prefrontal structures. Overall, the results indicate that spatial neglect in PCA is related to inter-hemispheric perfusion asymmetries in fronto-parietal networks, with partially different neural correlates for line bisection and target cancellation.
authors.affiliation: INSERM UMR_S 975, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière (CRICM), Paris, France.
authors.forename: Katia
authors.initials: K
authors.lastname: Andrade
authors.forename: Aurélie
authors.initials: A
authors.lastname: Kas
authors.forename: Dalila
authors.initials: D
authors.lastname: Samri
authors.forename: Marie
authors.initials: M
authors.lastname: Sarazin
authors.forename: Bruno
authors.initials: B
authors.lastname: Dubois
authors.forename: Marie-Odile
authors.initials: MO
authors.lastname: Habert
authors.forename: Paolo
authors.initials: P
authors.lastname: Bartolomeo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001284:Atrophy; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000473:pathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000473:pathology / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology; D013028:Space Perception / Q000502:physiology*; D015899:Tomography, Emission-Computed, Single-Photon; D014796:Visual Perception / Q000502:physiology*