Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
Institute of Cognitive Neuroscience, University College London Medical School, London, UK.
J Neurol Neurosurg Psychiatry. 2019 Sep;90(9):965-974. doi: 10.1136/jnnp-2018-320168. Epub 2019 May 9.
Limbic encephalitis associated with antibodies to components of the voltage-gated potassium channel complex (VGKCC-Ab-LE) often leads to hippocampal atrophy and persistent memory impairment. Its long-term impact on regions beyond the hippocampus, and the relationship between brain damage and cognitive outcome, are poorly understood. We investigated the nature of structural and functional brain abnormalities following VGKCC-Ab-LE and its role in residual memory impairment.
A cross-sectional group study was conducted. Twenty-four VGKCC-Ab-LE patients (20 male, 4 female; mean (SD) age 63.86 (11.31) years) were recruited post-acutely along with age- and sex-matched healthy controls for neuropsychological assessment, structural MRI and resting-state functional MRI (rs-fMRI). Structural abnormalities were determined using volumetry and voxel-based morphometry; rs-fMRI data were analysed to investigate hippocampal functional connectivity (FC). Associations of memory performance with neuroimaging measures were examined.
Patients showed selective memory impairment. Structural analyses revealed focal hippocampal atrophy within the medial temporal lobes, correlative atrophy in the mediodorsal thalamus, and additional volume reduction in the posteromedial cortex. There was no association between regional volumes and memory performance. Instead, patients demonstrated reduced posteromedial cortico-hippocampal and inter-hippocampal FC, which correlated with memory scores (r = 0.553; r = 0.582, respectively). The latter declined as a function of time since the acute illness (r = -0.531).
VGKCC-Ab-LE results in persistent isolated memory impairment. Patients have hippocampal atrophy with further reduced mediodorsal thalamic and posteromedial cortical volumes. Crucially, reduced FC of remaining hippocampal tissue correlates more closely with memory function than does regional atrophy.
与电压门控钾通道复合物（VGKCC-Ab-LE）抗体相关的边缘脑炎常导致海马萎缩和持续性记忆障碍。其对海马以外区域的长期影响以及脑损伤与认知结果之间的关系尚不清楚。我们研究了 VGKCC-Ab-LE 后大脑结构和功能的异常及其在残留记忆障碍中的作用。
进行了一项横断面组研究。招募了 24 名 VGKCC-Ab-LE 患者（20 名男性，4 名女性；平均（SD）年龄 63.86（11.31）岁）和年龄、性别匹配的健康对照组进行神经心理学评估、结构磁共振成像和静息状态功能磁共振成像（rs-fMRI）。使用体积测量和基于体素的形态测量法确定结构异常；分析 rs-fMRI 数据以研究海马功能连接（FC）。检查了记忆表现与神经影像学测量之间的关联。
患者表现出选择性记忆障碍。结构分析显示内侧颞叶内的局灶性海马萎缩，中背侧丘脑的相关性萎缩以及后内侧皮质的额外体积减少。区域体积与记忆表现之间没有关联。相反，患者表现出后内侧皮质-海马和海马间 FC 降低，与记忆评分相关（r = 0.553；r = 0.582）。后者随自急性疾病以来的时间呈下降趋势（r = -0.531）。
VGKCC-Ab-LE 导致持续性孤立性记忆障碍。患者有海马萎缩，中背侧丘脑和后内侧皮质体积进一步减少。至关重要的是，残留海马组织的 FC 降低与记忆功能的相关性比区域萎缩更密切。
