Vascular cognitive impairment, no dementia (VCIND) refers to cognitive deficits associated with underlying vascular causes that are insufficient to confirm a diagnosis of dementia. The default mode network (DMN) is a large-scale brain network of interacting brain regions involved in attention, working memory and executive function. The role of DMN white matter integrity in cognitive deficits of VCIND patients is unclear. Using diffusion tensor imaging (DTI), this study was carried out to investigate white matter microstructural changes in the DMN in VCIND patients and their contributions to cognitive deficits. Thirty-one patients with subcortical VCIND and twenty-two healthy elderly subjects were recruited. All patients underwent neuropsychological assessments and DTI examination. Voxel-based analyses were performed to extract fractional anisotropy (FA) and mean diffusivity (MD) measures in the DMN. Compared with the healthy elderly subjects, patients diagnosed with subcortical VCIND presented with abnormal white matter integrity in several key hubs of the DMN. The severity of damage in the white matter microstructure in the DMN significantly correlated with cognitive dysfunction. Mediation analyses demonstrated that DTI values could account for attention, executive and language impairments, and partly mediated global cognitive dysfunction in the subcortical VCIND patients. DMN integrity is significantly impaired in subcortical VCIND patients. The disrupted DMN connectivity could explain the attention, language and executive dysfunction, which indicates that the white matter integrity of the DMN may be a neuroimaging marker for VCIND.

中文翻译：

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默认模式网络完整性更改会导致皮层下血管认知功能障碍（无痴呆）中的认知缺陷。

血管性认知功能障碍，无痴呆症（VCIND）是指与潜在血管原因相关的认知缺陷，不足以证实痴呆症的诊断。默认模式网络（DMN）是一个大规模的大脑网络，由交互的大脑区域组成，涉及注意力，工作记忆和执行功能。DMN白质完整性在VCIND患者认知功能障碍中的作用尚不清楚。使用扩散张量成像（DTI），进行了这项研究，以调查VCIND患者DMN中白质微结构的变化及其对认知缺陷的影响。招募了31位皮质下VCIND患者和22位健康的老年受试者。所有患者均接受了神经心理学评估和DTI检查。进行基于体素的分析以提取DMN中的分数各向异性（FA）和平均扩散率（MD）量度。与健康的老年受试者相比，诊断为皮质下VCIND的患者在DMN的多个关键枢纽中表现出异常的白质完整性。DMN中白质微结构受损的严重程度与认知功能障碍密切相关。中介分析表明，DTI值可以解释皮质下VCIND患者的注意力，执行力和语言障碍，以及部分介导的整体认知功能障碍。在皮层下的VCIND患者中，DMN的完整性明显受损。DMN连接中断可能解释了注意力，语言和执行功能障碍，