Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ROC.
Mov Disord. 2013 Mar;28(3):362-9. doi: 10.1002/mds.25314. Epub 2013 Jan 16.
Multiple system atrophy of the cerebellar type is a sporadic neurodegenerative disorder of the central nervous system. We hypothesized that the white matter degeneration of the cerebellum and pons in this disease may cause a breakdown of cerebellar structural networks and further reduce the network efficiency of cerebellar-connected cerebral regions. Diffusion tensor tractography was used to construct the structural networks of 19 cerebellar-type multiple system atrophy patients, who were compared with 19 age- and sex-matched controls. Graph theory was used to assess the small-world properties and topological organization of structure networks in both the control and patient groups. Our results showed that the cerebellar-type multiple system atrophy patients exhibited altered small-world architecture with significantly increased characteristic shortest path lengths and decreased clustering coefficients. We also found that white matter degeneration in the cerebellum was characterized by reductions in network strength (number and integrity of fiber connections) of the cerebellar regions, which further induced extensively decreased network efficiency for numerous cerebral regions. Finally, we found that the reductions in nodal efficiency of the cerebellar lobules and bilateral sensorimotor, prefrontal, and basal ganglia regions negatively correlated with the severity of ataxia for the cerebellar-type multiple system atrophy patients. This study demonstrates for the first time that the brains of cerebellar-type multiple system atrophy patients exhibit disrupted topological organization of white matter structural networks. Thus, this study provides structural evidence of the relationship between abnormalities of white matter integrity and network efficiency that occurs in cerebellar-type multiple system atrophy.
小脑型多系统萎缩是一种散发性中枢神经系统退行性疾病。我们假设，这种疾病中小脑和脑桥的白质变性可能导致小脑结构网络的崩溃，并进一步降低与小脑相连的脑区的网络效率。我们使用弥散张量纤维束追踪技术构建了 19 例小脑型多系统萎缩患者的结构网络，并将其与 19 名年龄和性别匹配的对照者进行了比较。我们使用图论评估了对照组和患者组结构网络的小世界属性和拓扑组织。结果表明，小脑型多系统萎缩患者表现出改变的小世界架构，特征最短路径长度显著增加，聚类系数降低。我们还发现，小脑白质变性的特征是小脑区域网络强度（纤维连接的数量和完整性）降低，这进一步导致许多脑区的网络效率广泛降低。最后，我们发现小脑叶和双侧感觉运动、前额叶和基底节区域的节点效率降低与小脑型多系统萎缩患者的共济失调严重程度呈负相关。这项研究首次证明，小脑型多系统萎缩患者的大脑表现出白质结构网络拓扑组织的破坏。因此，本研究提供了小脑型多系统萎缩中白质完整性异常与网络效率之间关系的结构证据。
