Relationship Between DTI Metrics and Cognitive Function in Alzheimer's Disease
Relationship Between DTI Metrics and Cognitive Function in Alzheimer's Disease
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DOI：
10.3389/fnagi.2018.00436
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发表时间：
2019-01-09
影响因子：
4.8
通讯作者：
Gawryluk, Jodie R.
中科院分区：
文献类型：
--
作者：
Mayo, Chantel D.;Garcia-Barrera, Mauricio A.;Gawryluk, Jodie R.
简介：阿尔茨海默病（AD）是一种神经退行性疾病，其临床表现以记忆障碍和执行功能障碍为特征。我们的研究小组之前证明，与健康老年人相比，AD 患者的白质微观结构指标发生了显着变化。我们的目的是进一步研究 AD 中白质微观结构与认知功能（包括记忆和执行功能）之间的关系。方法：从 AD Neuroimaging Initiative 数据库中下载 49 名 AD 患者和 48 名匹配的健康老年人的弥散张量成像 (DTI) 和神经心理学数据。研究了全脑分数各向异性（FA）、平均扩散率（MD）、轴向扩散率（AxD）、径向扩散率（RD）以及记忆和执行功能的综合评分之间的关系。我们还使用基于束的空间统计来考虑体素关系。结果：正如预期的那样，与健康老年人相比，AD 患者在记忆和执行功能测试中的综合得分较低，并且白质完整性受到破坏（低 FA、高 MD、AxD 和 RD），包括海马体在内的广泛区域。当 AD 组和健康老年人组合并时，我们发现 DTI 指标 (FA/MD/AxD/RD) 与大脑广泛区域（包括内侧颞区）的记忆评分之间存在显着关系。我们还发现 DTI 指标（FA/MD/AxD/RD）与广泛区域（包括组合组中的额叶区域）的执行功能之间存在显着关系。然而，当单独检查各组时，没有发现任何一组的 DTI 指标（FA/MD/AxD/RD）与记忆表现之间存在显着关系。此外，我们没有发现 AD 组中 DTI 指标 (FA/MD/AxD/RD) 与执行功能之间存在任何显着关系，但我们确实观察到 FA/RD 与健康老年人的执行功能之间存在显着关系。结论：AD 中白质完整性受到破坏。在 AD 和健康老年人的混合样本中，白质微观结构和记忆以及执行认知测试表现之间的关联很明显。然而，在 AD 患者中，白质破坏程度与认知功能（记忆和执行能力）水平之间没有发现显着的线性关系。未来需要对 DTI 指标与 AD 认知功能之间的关系进行纵向研究，以确定 DTI 是否有潜力衡量 AD 的进展和/或治疗效果。
Introduction: Alzheimer's disease (AD) is a neurodegenerative disorder with a clinical presentation characterized by memory impairment and executive dysfunction. Our group previously demonstrated significant alterations in white matter microstructural metrics in AD compared to healthy older adults. We aimed to further investigate the relationship between white matter microstructure in AD and cognitive function, including memory and executive function.Methods: Diffusion tensor imaging (DTI) and neuropsychological data were downloaded from the AD Neuroimaging Initiative database for 49 individuals with AD and 48 matched healthy older adults. The relationship between whole-brain fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AxD), radial diffusivity (RD), and composite scores of memory and executive function was examined. We also considered voxel-wise relationships using Tract-Based Spatial Statistics.Results: As expected, individuals with AD had lower composite scores on tests of memory and executive function, as well as disrupted white matter integrity (low FA, high MD, AxD, and RD) relative to healthy older adults in widespread regions, including the hippocampus. When the AD and healthy older adult groups were combined, we found significant relationships between DTI metrics (FA/MD/AxD/RD) and memory scores across widespread regions of the brain, including the medial temporal regions. We also found significant relationships between DTI metrics (FA/MD/AxD/RD) and executive function in widespread regions, including the frontal areas in the combined group. However, when the groups were examined separately, no significant relationships were found between DTI metrics (FA/MD/AxD/RD) and memory performance for either group. Further, we did not find any significant relationships between DTI metrics (FA/MD/AxD/RD) and executive function in the AD group, but we did observe significant relationships between FA/RD, and executive function in healthy older adults.Conclusion: White matter integrity is disrupted in AD. In a mixed sample of AD and healthy elderly persons, associations between measures of white matter microstructure and memory and executive cognitive test performance were evident. However, no significant linear relationship between the degree of white matter disruption and level of cognitive functioning (memory and executive abilities) was found in those with AD. Future longitudinal studies of the relations between DTI metrics and cognitive function in AD are required to determine whether DTI has potential to measure progression of AD and/or treatment efficacy.