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Brain. 2015 Mar;138(Pt 3):746-60. doi: 10.1093/brain/awu389. Epub 2015 Jan 21.

White matter lesional predictors of chronic visual neglect: a longitudinal study.

Author information

1
1 INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France 2 Service de Médecine Physique et Réadaptation, Unité de Rééducation Neurologique CRF 'Les Trois Soleils' Boissise le Roi, France 3 Inserm UMR_S 1028, CNRS UMR 5292, ImpAct, centre des neurosciences de Lyon, université Lyon-1, 16, avenue Lépine 69676 Bron, France.
2
1 INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France 4 Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, UK.
3
2 Service de Médecine Physique et Réadaptation, Unité de Rééducation Neurologique CRF 'Les Trois Soleils' Boissise le Roi, France.
4
1 INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France 5 AP-HP, Department of Neurology, IFR 70, Salpêtrière Hospital, Paris, France.
5
3 Inserm UMR_S 1028, CNRS UMR 5292, ImpAct, centre des neurosciences de Lyon, université Lyon-1, 16, avenue Lépine 69676 Bron, France 6 Service de médecine physique et réadaptation neurologique, hospital Henry-Gabrielle, hospice civils de Lyon, 20, route de Vourles, Saint-Genis-Laval, France.
6
1 INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France 5 AP-HP, Department of Neurology, IFR 70, Salpêtrière Hospital, Paris, France 7 Department of Psychology, Catholic University, Milan, Italy paolo.bartolomeo@icm-institute.org.

Abstract

Chronic visual neglect prevents brain-damaged patients from returning to an independent and active life. Detecting predictors of persistent neglect as early as possible after the stroke is therefore crucial to plan the relevant interventions. Neglect signs do not only depend on focal brain lesions, but also on dysfunction of large-scale brain networks connected by white matter bundles. We explored the relationship between markers of axonal degeneration occurring after the stroke and visual neglect chronicity. A group of 45 patients with unilateral strokes in the right hemisphere underwent cognitive testing for neglect twice, first at the subacute phase (<3 months after onset) and then at the chronic phase (>1 year). For each patient, magnetic resonance imaging including diffusion sequences was performed at least 4 months after the stroke. After masking each patient's lesion, we used tract-based spatial statistics to obtain a voxel-wise statistical analysis of the fractional anisotropy data. Twenty-seven patients had signs of visual neglect at initial testing. Only 10 of these patients had recovered from neglect at follow-up. When compared with patients without neglect, the group including all subacute neglect patients had decreased fractional anisotropy in the second (II) and third (III) branches of the right superior longitudinal fasciculus, as well as in the splenium of the corpus callosum. The subgroup of chronic patients showed reduced fractional anisotropy in a portion the splenium, the forceps major, which provides interhemispheric communication between regions of the occipital lobe and of the superior parietal lobules. The severity of neglect correlated with fractional anisotropy values in superior longitudinal fasciculus II/III for subacute patients and in its caudal portion for chronic patients. Our results confirm a key role of fronto-parietal disconnection in the emergence and chronic persistence of neglect, and demonstrate an implication of caudal interhemispheric disconnection in chronic neglect. Splenial disconnection may prevent fronto-parietal networks in the left hemisphere from resolving the activity imbalance with their right hemisphere counterparts, thus leading to persistent neglect.

KEYWORDS:

MRI-DTI; axonal degeneration; chronic visual neglect; corpus callosum; fronto-parietal networks

PMID:
25609686
PMCID:
PMC4339774
DOI:
10.1093/brain/awu389
[Indexed for MEDLINE]
Free PMC Article

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