Posterior cingulum white matter disruption and its associations with verbal memory and stroke risk in mild cognitive impairment.
Posterior cingulum white matter disruption and its associations with verbal memory and stroke risk in mild cognitive impairment.
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DOI：
10.3233/jad-2012-102103
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Bondi MW
中科院分区：
文献类型：
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作者：
Delano-Wood L;Stricker NH;Sorg SF;Nation DA;Jak AJ;Woods SP;Libon DJ;Delis DC;Frank LR;Bondi MW
内侧颞叶和颞顶叶脑区是阿尔茨海默病（AD）中最早发生病理生理学改变的新皮质部位之一，尽管这些区域中潜在的白色物质变化鲜为人知。我们采用扩散张量成像来评估诊断为轻度认知障碍（MCI）的参与者的区域白色完整性的早期改变。检查了以下感兴趣区域（ROI）：1）前扣带（AC）; 2）后扣带（PC）; 3）胼胝体外侧; 4）胼胝体压部;以及5）内囊后肢作为对照部位。根据认知状态将40名非痴呆受试者分为人口统计学相似的组（MCI：n = 20;正常对照：n = 20），并获得每个ROI的各向异性分数（FA）估计值。MCI参与者显示出更大的后部白色物质（即，PC，压部），但不是前部白色物质（即，在调整了年龄、中风风险和全脑体积后，AC，AC）的变化。后白色物质的FA差异最好由径向扩散率的变化而不是轴向扩散率的变化来解释。PC FA也与海马体积以及言语记忆测试的表现显著正相关，而中风风险与海马体积显著相关，与PC FA无关。在研究MCI人群的亚型时，遗忘型MCI参与者相对于非遗忘型MCI参与者表现出较低的PC白色物质完整性。研究结果表明，MCI相关的认知变化的发展涉及后部微结构白色物质变性，并表明PC的FA减少可能是AD风险的候选神经影像学标志物。
Medial temporal lobe and temporoparietal brain regions are among the earliest neocortical sites to undergo pathophysiologic alterations in Alzheimer’s disease (AD), although the underlying white matter changes in these regions is less well known. We employed diffusion tensor imaging to evaluate early alterations in regional white matter integrity in participants diagnosed with mild cognitive impairment (MCI). The following regions of interests (ROIs) were examined: 1) anterior cingulum (AC); 2) posterior cingulum (PC); 3) genu of the corpus callosum; 4) splenium of the corpus callosum; and 5) as a control site for comparison, posterior limb of the internal capsule. Forty nondemented participants were divided into demographically-similar groups based on cognitive status (MCI: n = 20; normal control: n = 20), and fractional anisotropy (FA) estimates of each ROI were obtained. MCI participants showed greater posterior white matter (i.e., PC, splenium) but not anterior white matter (i.e., AC, genu) changes, after adjusting for age, stroke risk, and whole brain volume. FA differences of the posterior white matter were best accounted for by changes in radial but not axial diffusivity. PC FA was also significantly positively correlated with hippocampal volume as well as with performance on tests of verbal memory, whereas stroke risk was significantly correlated with genu FA and was unrelated to PC FA. When investigating subtypes of our MCI population, amnestic MCI participants showed lower PC white matter integrity relative to those with non-amnestic MCI. Findings implicate involvement of posterior microstructural white matter degeneration in the development of MCI-related cognitive changes and suggest that reduced FA of the PC may be a candidate neuroimaging marker of AD risk.