Data from: White matter alterations in Parkinson's disease with normal cognition precede grey matter atrophy

Introduction: While progressive MRI brain changes characterize advanced Parkinson's disease (PD), little has been discovered about structural alterations in the earliest phase of the disease, i.e. in patients with motor symptoms and with normal cognition. Our study aimed to detect grey matter (GM) and white matter (WM) changes in PD patients without cognitive impairment. Methods: Twenty PD patients and twenty-one healthy controls (HC) were tested for attention, executive function, working memory, and visuospatial and language domains. High-resolution T1-weighted and 60 directional diffusion-weighted 3T MRI images were acquired. The cortical, deep GM and WM volumes and density, as well as the diffusion properties of WM, were calculated. Analyses were repeated on data flipped to the side of the disease origin. Results: PD patients did not show any significant differences from HC in cognitive functioning or in brain volumes. Decreased GM intensity was found in the left superior parietal lobe in the right (p<0.02) and left (p<0.01) flipped data. The analysis of original, un-flipped data demonstrated elevated axial diffusivity (p<0.01) in the superior and anterior corona radiata, internal capsule, and external capsule in the left hemisphere of PD relative to HC, while higher mean and radial diffusivity were discovered in the right (p<0.02 and p<0.03, respectively) and left (p<0.02 and p<0.02, respectively) in the fronto-temporal WM utilizing flipped data. Conclusions: PD patients without cognitive impairment and GM atrophy demonstrated widespread alterations of WM microstructure. Thus, WM impairment in PD might be a sensitive sign preceding the neuronal loss in associated GM regions.引言：尽管脑部进行性磁共振成像（MRI）改变是晚期帕金森病（Parkinson's disease, PD）的典型特征，但目前对该病最早期阶段，即存在运动症状且认知功能正常的患者的脑部结构改变仍知之甚少。本研究旨在探究无认知障碍的帕金森病患者的灰质（grey matter, GM）与白质（white matter, WM）变化。 方法：本研究纳入20名帕金森病患者与21名健康对照（healthy controls, HC），对其注意力、执行功能、工作记忆以及视空间与语言认知域进行评估。采集高分辨率T1加权成像与60方向扩散加权3T MRI图像。计算皮层、深部灰质、白质的体积与密度，以及白质的扩散特性。对按病灶侧翻转的数据重复进行上述分析。 结果：与健康对照相比，无认知障碍的帕金森病患者在认知功能与脑体积方面均未出现显著差异。在翻转后的数据中，双侧（右侧翻转数据p<0.02、左侧翻转数据p<0.01）的左侧顶上叶灰质强度出现降低。对原始未翻转数据的分析显示，相较于健康对照，帕金森病患者左侧半球的上放射冠、前放射冠、内囊及外囊的轴向扩散系数显著升高（p<0.01）；而采用翻转数据时，额颞叶白质的右侧（平均扩散系数p<0.02、径向扩散系数p<0.03）与左侧（平均扩散系数p<0.02、径向扩散系数p<0.02）的平均与径向扩散系数均显著升高。 结论：无认知障碍且存在灰质萎缩的帕金森病患者，其白质微观结构存在广泛改变。由此可见，帕金森病患者的白质损伤可能是相关灰质区域神经元丢失之前的敏感标志物。