Department of Neurology, Medical School, University of Ioannina, Stavrou Niarchou Av., University Campus, 45110, Ioannina, Greece.
Department of Medical Physics, Medical School, University of Ioannina, Stavrou Niarchou Av., University Campus, 45110, Ioannina, Greece.
Brain Imaging Behav. 2019 Feb;13(1):232-240. doi: 10.1007/s11682-018-9863-7.
The purpose of the present study was to investigate the pattern of white matter (WM) changes associated with Parkinson's disease (PD)-related cognitive impairment by using fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) measures. Diffusion Tensor Imaging (DTI) was performed in 21 PD-patients with dementia (PDD) and in an age-matched control group including 40 PD-patients without dementia (PD-CTRL). The Parkinson's disease-Cognitive Rating Scale (PD-CRS) was used for patients' neuropsychological assessment. Local microstructural WM differences associated with the presence of cognitive impairment were tested using tract-based spatial statistics analysis. Multiple regression models investigated the association of DTI indices with total PD-CRS score, PD-CRS raw items and other clinical measures across the whole study sample. Significant FA decreases were found in PDD compared to PD-CTRL patients mainly in the body of corpus callosum, corona radiata and cingulum. Lower PD-CRS score was significantly associated with decreased FA, MD and AD values in multiple WM tracts primarily located in prefrontal and limbic areas as well as across the corpus callosum. Lower performance in specific PD-CRS raw items was also associated with FA decreases in major WM tracts. The results suggest that multifocal microstructural changes of WM accompany the transition from normal to demented cognitive state in PD-patients. The corpus callosum, the corona radiata and the cingulum are among the regions mostly affected during this course. A progressive axonal degeneration is proposed as a key underlying mechanism.
本研究旨在通过各向异性分数（FA）、平均扩散系数（MD）、轴向扩散系数（AD）和径向扩散系数（RD）测量，探讨与帕金森病（PD）相关认知障碍相关的白质（WM）变化模式。对 21 例痴呆（PDD）PD 患者和 40 例年龄匹配的无痴呆（PD-CTRL）PD 患者进行了弥散张量成像（DTI）检查。采用帕金森病认知评定量表（PD-CRS）对患者进行神经心理学评估。使用基于束的空间统计学分析检测与认知障碍存在相关的局部微观结构 WM 差异。多元回归模型调查了整个研究样本中 DTI 指数与总 PD-CRS 评分、PD-CRS 原始项目和其他临床指标的相关性。与 PD-CTRL 患者相比，PDD 患者的 FA 降低主要位于胼胝体体部、放射冠和扣带。较低的 PD-CRS 评分与多个 WM 束中的 FA、MD 和 AD 值降低显著相关，这些 WM 束主要位于前额叶和边缘区域以及胼胝体。特定 PD-CRS 原始项目的表现较差也与主要 WM 束中的 FA 降低有关。研究结果表明，WM 的多灶性微观结构变化伴随着 PD 患者从正常认知状态向痴呆认知状态的转变。胼胝体、放射冠和扣带是在此过程中受影响最大的区域之一。提出进行性轴突变性是一个关键的潜在机制。
