Even clinically “asymptomatic” carotid stenosis is associated with multidomain cognitive impairment, gray matter (GM) atrophy, and silent lesion. However, the links between them remain unclear. Using structural MRI data, we examined GM asymmetry index (AI) and white matter hyperintensity (WMH) in 24 patients with severe asymptomatic carotid stenosis (SACS), 24 comorbidity-matched controls, and independent samples of 84 elderly controls and 22 young adults. As compared to controls, SACS patients showed worse verbal memories, higher WMH burden, and right-lateralized GM in posterior middle temporal and mouth-somatomotor regions. These clusters extended to pars triangularis, lateral temporal, and cerebellar regions, when compared with young adults. Further, a full-path of WMH burden (X), GM volume (atrophy, M1), AI (asymmetry, M2), and neuropsychological variables (Y) through a serial mediation model was analyzed. This analysis identified that left-dominated GM atrophy and right-lateralized asymmetry in the posterior middle temporal cortex mediated the relationship between WMH burden and recall memory in SACS patients. These results suggest that the unbalanced hemispheric atrophy in the posterior middle temporal cortex is crucial to mediating relationship between WMH burden and verbal recall memories, which may underlie accelerated aging and cognitive deterioration in patients with SACS and other vascular cognitive impairment.

中文翻译：

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无症状颈动脉狭窄中的灰质不对称

即使是临床上“无症状”的颈动脉狭窄也与多域认知障碍、灰质 (GM) 萎缩和无症状病变有关。然而，它们之间的联系仍不清楚。使用结构 MRI 数据，我们检查了 24 名严重无症状颈动脉狭窄 (SACS) 患者、24 名合并症匹配对照以及 84 名老年人对照和 22 名年轻人的独立样本的 GM 不对称指数 (AI) 和白质高信号 (WMH)。与对照组相比，SACS 患者在颞中后部和口腔躯体运动区域表现出更差的言语记忆、更高的 WMH 负担和右侧 GM。与年轻人相比，这些集群扩展到三角部、颞侧和小脑区域。此外，WMH 负担（X）、GM 体积（萎缩，M1）、AI（不对称，M2）、通过串行中介模型分析神经心理变量（Y）。该分析发现，左侧为主的 GM 萎缩和后中颞叶皮层右侧不对称性介导了 SACS 患者 WMH 负担与回忆记忆之间的关系。这些结果表明，后中颞叶皮质的不平衡半球萎缩对于调节 WMH 负担和言语回忆之间的关系至关重要，这可能是 SACS 和其他血管性认知障碍患者加速衰老和认知恶化的基础。该分析发现，左侧为主的 GM 萎缩和后中颞叶皮层右侧不对称性介导了 SACS 患者 WMH 负担与回忆记忆之间的关系。这些结果表明，后中颞叶皮质的不平衡半球萎缩对于调节 WMH 负担和言语回忆之间的关系至关重要，这可能是 SACS 和其他血管性认知障碍患者加速衰老和认知恶化的基础。该分析发现，左侧为主的 GM 萎缩和后中颞叶皮层右侧不对称性介导了 SACS 患者 WMH 负担与回忆记忆之间的关系。这些结果表明，后中颞叶皮质的不平衡半球萎缩对于调节 WMH 负担和言语回忆之间的关系至关重要，这可能是 SACS 和其他血管性认知障碍患者加速衰老和认知恶化的基础。