Abstract：
The Postural Instability/Gait Difficulty (PIGD) subtype of Parkinson\'s disease (PD) has a faster disease progression, a higher risk of cognitive and motor decline, yet the alterations of structural topological organization remain unknown. Diffusion Tensor Imaging (DTI) and 3D-TI scanning were conducted on 31 PD patients with PIGD (PD-PIGD), 30 PD patients without PIGD (PD-non-PIGD) and 35 Healthy Controls (HCs). Structural networks were constructed using DTI brain white matter fiber tractography. A graph theory approach was applied to characterize the topological properties of complex structural networks, and the relationships between significantly different network metrics and motor deficits were analyzed within the PD-PIGD group. PD-PIGD patients exhibited increased shortest path length compared with PD-non-PIGD and HCs (P < 0.05, respectively). Additionally, PD-PIGD patients exhibited decreased nodal properties, mainly in the cerebellar vermis, prefrontal cortex, paracentral lobule, and visual regions. Notably, the degree centrality of the cerebellar vermis was negatively correlated with the PIGD score (r = -0.390; P = 0.030) and Unified Parkinson\'s Disease Rating Scale Part III score (r = -0.436; P = 0.014) in PD-PIGD patients. Furthermore, network-based statistical analysis revealed decreased structural connectivity between the prefrontal lobe, putamen, supplementary motor area, insula, and cingulate gyrus in PD-PIGD patients. Our findings demonstrated that PD-PIGD patients existed abnormal structural connectomes in the cerebellar vermis, frontal-parietal cortex and visual regions. These topological differences can provide a topological perspective for understanding the potential pathophysiological mechanisms of PIGD in PD.
摘要：
帕金森病（PD）的姿势不稳定/步态困难（PIGD）亚型具有更快的疾病进展，认知和运动衰退的风险更高，然而，结构拓扑组织的变化仍然未知。对31例PD合并PIGD(PD-PIGD)患者进行扩散张量成像(DTI)和3D-TI扫描,30例无PIGD的PD患者(PD-非PIGD)和35例健康对照(HC)。使用DTI脑白质纤维束描记术构建结构网络。应用图论方法来表征复杂结构网络的拓扑特性，并分析了PD-PIGD组中明显不同的网络指标与运动缺陷之间的关系。与PD-non-PIGD和HC相比，PD-PIGD患者的最短路径长度增加（分别为P<0.05）。此外,PD-PIGD患者表现出淋巴结特性下降，主要在小脑的疣,前额叶皮质,旁中央小叶,和视觉区域。值得注意的是,在PD-PIGD患者中,小脑软骨的程度中心性与PIGD评分(r=-0.390;P=0.030)和统一帕金森病评定量表第III部分评分(r=-0.436;P=0.014)呈负相关.此外，基于网络的统计分析显示前额叶之间的结构连通性降低，壳核,辅助电机区域,脑岛,PD-PIGD患者的扣带回。我们的研究结果表明，PD-PIGD患者在小脑疣中存在异常的结构连接体，额叶-顶叶皮层和视觉区域。这些拓扑差异可以为理解PIGD在PD中的潜在病理生理机制提供拓扑观点。
