Lunven Marine, Thiebaut De Schotten Michel, Bourlon Clémence, Duret Christophe, Migliaccio Raffaella, Rode Gilles, Bartolomeo Paolo
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.
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.
Brain. 2015 Mar;138(Pt 3):746-60. doi: 10.1093/brain/awu389. Epub 2015 Jan 21.
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.
慢性视觉忽视使脑损伤患者无法恢复独立且积极的生活。因此，在中风后尽早发现持续性忽视的预测因素对于规划相关干预措施至关重要。忽视症状不仅取决于局灶性脑损伤，还取决于由白质束连接的大规模脑网络功能障碍。我们探讨了中风后发生的轴突退变标志物与视觉忽视慢性化之间的关系。一组45例右半球单侧中风患者接受了两次忽视认知测试，第一次在亚急性期（发病后<3个月），第二次在慢性期（>1年）。对于每位患者，在中风后至少4个月进行了包括扩散序列在内的磁共振成像检查。在对每位患者的病变进行掩蔽后，我们使用基于束的空间统计学方法对分数各向异性数据进行体素级统计分析。27例患者在初次测试时有视觉忽视症状。这些患者中只有10例在随访时从忽视中恢复。与无忽视的患者相比，包括所有亚急性忽视患者的组在右上纵束的第二（II）和第三（III）分支以及胼胝体压部的分数各向异性降低。慢性患者亚组在胼胝体压部的一部分、主要钳部表现出分数各向异性降低，主要钳部在枕叶和顶上小叶区域之间提供半球间通信。亚急性患者的忽视严重程度与上纵束II/III的分数各向异性值相关，慢性患者的忽视严重程度与上纵束尾部的分数各向异性值相关。我们的结果证实了额顶叶连接中断在忽视的出现和慢性持续中的关键作用，并表明尾侧半球间连接中断在慢性忽视中的作用。胼胝体压部连接中断可能会阻止左半球的额顶叶网络解决与其右半球对应网络的活动失衡问题，从而导致持续性忽视。
