Cooley Sarah A, Cabeen Ryan P, Laidlaw David H, Conturo Thomas E, Lane Elizabeth M, Heaps Jodi M, Bolzenius Jacob D, Baker Laurie M, Salminen Lauren E, Scott Staci E, Paul Robert H
a Department of Psychology , University of Missouri-Saint Louis , Saint Louis , MO , USA.
J Clin Exp Neuropsychol. 2015;37(1):61-9. doi: 10.1080/13803395.2014.985636. Epub 2014 Dec 18.
Much of the mild cognitive impairment (MCI) neuroimaging literature has exclusively focused on regions associated with Alzheimer's disease. Little research has examined white matter abnormalities of other brain regions, including those associated with visual processing, despite evidence that other brain abnormalities appear in these regions in early disease stages.
Diffusion tensor imaging (DTI) was utilized to examine participants (n = 44) that completed baseline imaging as part of a longitudinal healthy aging study. Participants were divided into two groups based on scores from the Montreal Cognitive Assessment (MoCA), a brief screening tool for MCI. Participants who scored <26 were defined as "probable MCI" while those who scored ≥26 were labeled cognitively healthy. Two DTI indices were analyzed including fractional anisotropy (FA) and mean diffusivity (MD). DTI values for white matter in the lingual gyrus, cuneus, pericalcarine, fusiform gyrus, and all four lobes were compared using multivariate analysis of variance (MANOVA). Regression analyses examined the relationship between DTI indices and total MoCA score.
RESULTS revealed significantly lower FA in the probable MCI group in the cuneus, fusiform, pericalcarine, and occipital lobe, and significantly higher MD in the temporal lobe. Fusiform FA and temporal lobe MD were significantly related to total MoCA score after accounting for age and education.
RESULTS indicate that there are posterior white matter microstructural changes in individuals with probable MCI. These differences demonstrate that white matter abnormalities are evident among individuals with probable MCI in regions beyond those commonly associated with Alzheimer's disease and anterior brain aging patterns.
许多轻度认知障碍（MCI）神经影像学文献仅关注与阿尔茨海默病相关的区域。尽管有证据表明在疾病早期阶段其他脑区会出现异常，但很少有研究考察包括与视觉处理相关脑区在内的其他脑区的白质异常情况。
利用扩散张量成像（DTI）对作为纵向健康老龄化研究一部分完成基线成像的参与者（n = 44）进行检查。根据蒙特利尔认知评估（MoCA）（一种MCI的简易筛查工具）的得分将参与者分为两组。得分<26分的参与者被定义为“可能的MCI”，而得分≥26分的参与者被标记为认知健康。分析了两个DTI指标，包括分数各向异性（FA）和平均扩散率（MD）。使用多变量方差分析（MANOVA）比较舌回、楔叶、距状周围、梭状回以及所有四个脑叶白质的DTI值。回归分析考察了DTI指标与MoCA总分之间的关系。
结果显示，可能的MCI组在楔叶、梭状回、距状周围和枕叶的FA显著降低，在颞叶的MD显著升高。在考虑年龄和教育因素后，梭状回FA和颞叶MD与MoCA总分显著相关。
结果表明，可能患有MCI的个体存在后部白质微观结构变化。这些差异表明，在可能患有MCI的个体中，白质异常在那些通常与阿尔茨海默病和前脑老化模式无关的区域也很明显。
