Miró Júlia, Gurtubay-Antolin Ane, Ripollés Pablo, Sierpowska Joanna, Juncadella Montse, Fuentemilla Lluís, Sánchez Verónica, Falip Mercè, Rodríguez-Fornells Antoni
Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, L'Hospitalet (Barcelona), Spain; Epilepsy Unit, Neurology Section, Hospital Universitari de Bellvitge (HUB), L'Hospitalet (Barcelona), Spain.
Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, L'Hospitalet (Barcelona), Spain.
Cortex. 2015 Jun;67:106-21. doi: 10.1016/j.cortex.2015.03.018. Epub 2015 Apr 1.
Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy. The most frequent pathologic finding in this condition is hippocampal sclerosis (HS). In addition, in a small proportion (14-23%) of refractory TLE patients, the presence of HS is bilateral. TLE involves grey matter (GM) and white matter (WM) abnormalities in a wide cortico-subcortical network. However, the impact of neuronal loss on specific WM fiber pathways and associated functional systems as well as seizure propagation pathways remains unclear. There is still much controversy regarding the role of the commissures (corpus callosum, hippocampal commissure and anterior commissure) in interhemispheric seizure propagation. This study aimed to investigate the integrity of WM interhemispheric connectivity in a singular sample of patients with TLE and bilateral HS using structural magnetic resonance imaging (MRI). We performed multimodal structural MRI [high resolution T1-weighted and diffusion tensor imaging (DTI)] analyses of seven patients with medically refractory TLE with bilateral HS, fourteen unilateral left TLE patients and fifteen matched healthy individuals. Whole-brain voxel-wise analysis techniques were used. These patients evidenced WM derangement [reduced fractional anisotropy (FA), increased mean diffusivity (MD) or reduced WM volume] in temporal and extratemporal tracks, but also in commissural pathways, compared to the unilateral left TLE patients and the control group. Presence of reduced FA or increased MD in the fornix, cingulum and uncinate fasciculus in addition to reduced WM volume in the fornix was also encountered. Neuropsychological assessment was performed without significant correlations with structural data. The current results support the idea that commissural pathways play a contributory role in interhemispheric TLE seizure propagation in bilateral HS and offer new perspectives about the long-term effects on interhemispheric connectivity associated with seizure propagation patterns in TLE patients.
颞叶癫痫（TLE）是局灶性癫痫最常见的形式。这种情况下最常见的病理发现是海马硬化（HS）。此外，在一小部分（14 - 23%）难治性TLE患者中，HS是双侧存在的。TLE涉及广泛的皮质 - 皮质下网络中的灰质（GM）和白质（WM）异常。然而，神经元丢失对特定白质纤维通路、相关功能系统以及癫痫发作传播通路的影响仍不清楚。关于连合纤维（胼胝体、海马连合和前连合）在半球间癫痫发作传播中的作用仍存在很多争议。本研究旨在使用结构磁共振成像（MRI），在一组患有TLE和双侧HS的患者样本中，研究白质半球间连接的完整性。我们对7例药物难治性双侧HS的TLE患者、14例左侧单侧TLE患者和15名匹配的健康个体进行了多模态结构MRI[高分辨率T1加权和扩散张量成像（DTI）]分析。采用全脑体素分析技术。与左侧单侧TLE患者和对照组相比，这些患者在颞叶和颞外通路以及连合通路中均表现出白质紊乱[分数各向异性（FA）降低、平均扩散率（MD）增加或白质体积减小]。还发现穹窿、扣带束和钩束的FA降低或MD增加，以及穹窿的白质体积减小。进行了神经心理学评估，但与结构数据无显著相关性。目前的结果支持这样一种观点，即连合通路在双侧HS的半球间TLE癫痫发作传播中起作用，并为TLE患者癫痫发作传播模式对半球间连接的长期影响提供了新的视角。
