Brain networks in posterior cortical atrophy: A single case tractography study and literature review

Raffaella Migliaccio, Federica Agosta, Monica N. Toba, Dalila Samri, Fabian Corlier, Leonardo C. de Souza, Marie Chupin, Michael Sharman, Maria L. Gorno-Tempini, Bruno Dubois, Massimo Filippi, Paolo Bartolomeo

Research output: Contribution to journalArticlepeer-review

Abstract

Posterior cortical atrophy (PCA) is rare neurodegenerative dementia, clinically characterized by a progressive decline in higher-visual object and space processing. After a brief review of the literature on the neuroimaging in PCA, here we present a study of the brain structural connectivity in a patient with PCA and progressive isolated visual and visuo-motor signs. Clinical and cognitive data were acquired in a 58-years-old patient (woman, right-handed, disease duration 18 months). Brain structural and diffusion tensor (DT) Magnetic Resonance Imaging (MRI) were obtained. A voxel-based morphometry (VBM) study was performed to explore the pattern of gray matter (GM) atrophy, and a fully automatic segmentation was assessed to obtain the hippocampal volumes. DT MRI-based tractography was used to assess the integrity of long-range white matter (WM) pathways in the patient and in six sex- and age-matched healthy subjects. This PCA patient had a clinical syndrome characterized by left visual neglect, optic ataxia, and left limb apraxia, as well as mild visuo-spatial episodic memory impairment. VBM study showed bilateral posterior GM atrophy with right predominance; DT MRI tractography demonstrated WM damage to the right hemisphere only, including the superior and inferior longitudinal fasciculi and the inferior fronto-occipital fasciculus, as compared to age-matched controls. The homologous left-hemisphere tracts were spared. No difference was found between left and right hippocampal volumes. These data suggest that selective visuo-spatial deficits typical of PCA might not result from cortical damage alone, but by a right-lateralized network-level dysfunction including WM damage along the major visual pathways.

Original languageEnglish
Pages (from-to)1298-1309
Number of pages12
JournalCortex
Volume48
Issue number10
DOIs
Publication statusPublished - Nov 2012

Keywords

  • Brain networks
  • Ideomotor apraxia
  • Neurodegeneration
  • Optic ataxia
  • Visuo-spatial attention

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology
  • Arts and Humanities (miscellaneous)
  • Developmental and Educational Psychology

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