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

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• 作者：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
• 关键词：Brain networks ; Visuo-spatial attention ; Optic ataxia ; Ideomotor apraxia ; Neurodegeneration
• 刊名：Cortex
• 出版年：2012
• 出版时间：November-December, 2012
• 年：2012
• 卷：48
• 期：10
• 页码：1298-1309
• 全文大小：904 K

文摘

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.