Boespflug Erin L, Eliassen James, Welge Jeffrey, Krikorian Robert
Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati Academic Health Center, Cincinnati, OH, USA.
Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati Academic Health Center, Cincinnati, OH, USA Department of Environmental Health (Division of Epidemiology & Biostatistics), University of Cincinnati Academic Health Center, Cincinnati, OH, USA.
J Alzheimers Dis. 2014;41(2):421-30. doi: 10.3233/JAD-131682.
While diagnostic criteria for Alzheimer's disease (AD) include neuroimaging biomarkers, there remains no definitive biomarker of mild cognitive impairment (MCI). MCI is a risk factor for AD that may be amenable to early intervention. Early decline in white matter (WM) integrity identified by diffusion tensor imaging (DTI) is a predictor of future progression of neurodegeneration.
Identify regionally specific WM differences between individuals with MCI and those with age-associated memory impairment (AAMI) and relationships with specific memory decrements.
DTI and neuropsychological data were acquired from 38 participants (23 MCI and 15 AAMI). A region of interest approach was used to evaluate regional differences between groups and correlative relationships with performance on memory tasks.
Fornix WM had higher mean (MD), radial (DR), and axial (DA) diffusivity in MCI participants relative to AAMI. Temporal stem (TS) WM had higher MD and DR in MCI than in AAMI. In MCI, TS MD and DR varied, while fornix MD and DR was uniformly high, and in AAMI, TS MD and DR were uniformly low and fornix MD and DR varied. In MCI, TS MD and DA were inversely associated with associative learning but not list learning.
In addition to supporting prior evidence implicating the fornix in early AD pathology, these data implicate a profile of neurodegeneration associated with early MCI. Further, they suggest that associative learning tasks are more sensitive to early neurodegeneration and may be useful in identifying individuals at risk for AD.
虽然阿尔茨海默病（AD）的诊断标准包括神经影像学生物标志物，但轻度认知障碍（MCI）仍没有明确的生物标志物。MCI是AD的一个风险因素，可能适合早期干预。通过扩散张量成像（DTI）确定的白质（WM）完整性早期下降是神经退行性变未来进展的一个预测指标。
确定MCI个体与年龄相关性记忆障碍（AAMI）个体之间区域特异性的WM差异以及与特定记忆减退的关系。
从38名参与者（23名MCI和15名AAMI）获取DTI和神经心理学数据。采用感兴趣区域方法评估组间区域差异以及与记忆任务表现的相关性。
相对于AAMI，MCI参与者的穹窿WM具有更高的平均扩散率（MD）、径向扩散率（DR）和轴向扩散率（DA）。颞叶干（TS）WM在MCI中的MD和DR高于AAMI。在MCI中，TS的MD和DR有所不同，而穹窿的MD和DR一直较高，在AAMI中，TS的MD和DR一直较低，穹窿的MD和DR有所不同。在MCI中，TS的MD和DA与联想学习呈负相关，但与列表学习无关。
这些数据除了支持先前将穹窿与早期AD病理联系起来的证据外，还表明了与早期MCI相关的神经退行性变特征。此外，它们表明联想学习任务对早期神经退行性变更敏感，可能有助于识别有AD风险的个体。
