Peller M, Zeuner K E, Munchau A, Quartarone A, Weiss M, Knutzen A, Hallett M, Deuschl G, Siebner H R
Department of Neurology, Christian-Albrechts-University Kiel, Kiel, Germany.
Brain. 2006 Oct;129(Pt 10):2697-708. doi: 10.1093/brain/awl181. Epub 2006 Jul 19.
Writer's cramp is a focal hand dystonia that specifically affects handwriting. Though writer's cramp has been attributed to a dysfunction of the basal ganglia, the role of the basal ganglia in the pathogenesis of writer's cramp remains to be determined. Seventeen patients with writer's cramp (nine females; age range: 24-71 years) and 17 healthy individuals (six females; age range: 27-68 years) underwent functional MRI (fMRI) while they discriminated the orientation of gratings delivered to the tip of the right index finger. Statistical parametric mapping was used to analyse the fMRI data. The significance level was set at a corrected P-value of 0.05. Relative to healthy controls, patients with writer's cramp showed a widespread bilateral increase in task-related activity in the putamen, caudate nucleus, internal globus pallidus and lateral thalamus. In these areas, hyperactivity was more pronounced in patients who had recently developed writer's cramp. The enhanced response of the basal ganglia to tactile input from the affected hand is compatible with the concept of impaired centre-surround inhibition within the basal ganglia-thalamic circuit and may lead to an excessive activation of sensorimotor cortical areas during skilled movements affected by dystonia. Outside the basal ganglia, dystonic patients showed task-related overactivity in visual cortical areas, left anterior insula and right intraparietal sulcus, but not in the primary or secondary sensory cortex. In addition, task-related activity in the cerebellar nuclei, posterior vermis, right paramedian cerebellar hemisphere and dorsal pons was inversely related with the severity of hand dystonia. Regional activity in these areas may reflect secondary adaptive reorganization at the systems level to compensate for the dysfunction in the basal ganglia-thalamic loop.
书写痉挛是一种局限性手部肌张力障碍，专门影响书写。尽管书写痉挛被认为是基底神经节功能障碍所致，但基底神经节在书写痉挛发病机制中的作用仍有待确定。17例书写痉挛患者（9例女性；年龄范围：24 - 71岁）和17名健康个体（6例女性；年龄范围：27 - 68岁）在辨别传递至右手食指指尖的光栅方向时接受了功能磁共振成像（fMRI）检查。采用统计参数映射分析fMRI数据。显著性水平设定为校正P值0.05。与健康对照相比，书写痉挛患者在壳核、尾状核、苍白球内部和外侧丘脑的任务相关活动出现广泛双侧增加。在这些区域，近期发生书写痉挛的患者活动亢进更为明显。基底神经节对患手触觉输入的反应增强与基底神经节 - 丘脑回路中中心 - 外周抑制受损的概念相符，并且可能导致在肌张力障碍影响的熟练运动过程中感觉运动皮层区域过度激活。在基底神经节之外，肌张力障碍患者在视觉皮层区域、左侧前岛叶和右侧顶内沟表现出任务相关的活动亢进，但在初级或次级感觉皮层未出现。此外，小脑核、小脑蚓部后部、右侧旁正中小脑半球和脑桥背侧的任务相关活动与手部肌张力障碍的严重程度呈负相关。这些区域的局部活动可能反映了系统水平的继发性适应性重组，以补偿基底神经节 - 丘脑环路的功能障碍。
