New Zealand Brain Research Institute, University of Otago, Christchurch, New Zealand.
Neurology. 2013 May 14;80(20):1841-9. doi: 10.1212/WNL.0b013e3182929f62. Epub 2013 Apr 17.
To characterize different stages of Parkinson disease (PD)-related cognitive decline using diffusion tensor imaging (DTI) and investigate potential relationships between cognition and microstructural integrity of primary white matter tracts.
Movement Disorder Society criteria were used to classify 109 patients with PD as having normal cognition (PD-N, n = 63), mild cognitive impairment (PD-MCI, n = 28), or dementia (PD-D, n = 18), and were compared with 32 matched controls. DTI indices were assessed across groups using tract-based spatial statistics, and multiple regression was used to assess association with cognitive and clinical measures.
Relative to controls, PD-N showed some increased mean diffusivity (MD) in corpus callosum, but no significantly decreased fractional anisotropy (FA). Decreased FA and increased MD were identified in PD-MCI and PD-D relative to controls. Only small areas of difference were observed in PD-MCI and PD-D compared with PD-N, while DTI metrics did not differ significantly between PD-MCI and PD-D. Executive function, attention, memory, and a composite measure of global cognition were associated with MD, primarily in anterior white matter tracts; only attention was associated with FA. These differences were independent of white matter hyperintensity load, which was also associated with cognition in PD.
PD is associated with spatially restricted loss of microstructural white matter integrity in patients with relatively normal cognition, and these alterations increase with cognitive dysfunction. Functional impairment in executive function, attention, and learning and memory appears associated with microstructural changes, suggesting that tract-based spatial statistics provides an early marker for clinically relevant cognitive impairment in PD.
使用弥散张量成像（DTI）描绘帕金森病（PD）相关认知障碍的不同阶段，并研究认知功能与主要白质束微观结构完整性之间的潜在关系。
采用运动障碍协会标准将 109 名 PD 患者分为认知正常（PD-N，n=63）、轻度认知障碍（PD-MCI，n=28）和痴呆（PD-D，n=18），并与 32 名匹配对照进行比较。使用基于束的空间统计学在各组中评估 DTI 指数，并使用多元回归评估与认知和临床测量的关联。
与对照组相比，PD-N 的胼胝体部分出现了一些平均弥散度（MD）增加，但各向异性分数（FA）没有显著降低。PD-MCI 和 PD-D 与对照组相比，FA 降低和 MD 增加。与 PD-N 相比，PD-MCI 和 PD-D 仅观察到较小的差异区域，而 PD-MCI 和 PD-D 之间的 DTI 指标没有显著差异。执行功能、注意力、记忆和整体认知的综合测量与 MD 相关，主要与前白质束相关；只有注意力与 FA 相关。这些差异与白质高信号负荷无关，白质高信号负荷也与 PD 中的认知有关。
PD 与认知相对正常的患者中空间受限的微观结构白质完整性丧失有关，并且这些改变随着认知功能障碍的增加而增加。执行功能、注意力和学习记忆的功能障碍与微观结构变化相关，表明基于束的空间统计学为 PD 中与临床相关的认知障碍提供了早期标志物。
