IntroductionThe normal hemispheric balance can be altered by the asymmetric sensorimotor signal elicited by Cervical Dystonia (CD), leading to motor and cognitive deficits.MethodsDirectional errors, peak velocities, movement and reaction times of pointing towards out-of-reach targets in the horizontal plane were analysed in 18 CD patients and in 11 aged-matched healthy controls.ResultsCD patients displayed a larger scatter of individual trials around the average pointing direction (variable error) than normal subjects, whatever the arm used, and the target pointed. When pointing in the left hemispace, all subjects showed a left deviation (constant error) with respect to the target position, which was significantly larger in CD patients than controls, whatever the direction of the abnormal neck torsion could be. Reaction times were larger and peak velocities lower in CD patients than controls.DiscussionDeficits in the pointing precision of CD patients may arise from a disruption of motor commands related to the sensorimotor imbalance, from a subtle increase in shoulder rigidity or from a reduced agonists activation. Their larger left bias in pointing to left targets could be due to an increased right parietal dominance, independently upon the direction of head roll/jaw rotation which expands the left space representation and/or increases left spatial attention. These deficits may potentially extend to tracking and gazing objects in the left hemispace, leading to reduced skills in spatial-dependent motor and cognitive performance.

中文翻译：

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颈肌张力障碍患者的指向

简介颈肌张力障碍 (CD) 引起的不对称感觉运动信号可能会改变正常的半球平衡，从而导致运动和认知缺陷。方法指向水平面上超出范围的目标的方向误差、峰值速度、运动和反应时间对 18 名 CD 患者和 11 名年龄匹配的健康对照进行了分析。结果 CD 患者在平均指向方向（可变误差）方面的个体试验显示出比正常受试者更大的分散性，无论使用什么手臂和目标指向。当指向左半空间时，所有受试者都表现出相对于目标位置的左偏差（恒定误差），无论异常颈部扭转的方向如何，CD 患者的左偏差明显大于对照组。与对照组相比，CD 患者的反应时间更长，峰值速度更低。讨论 CD 患者的指向精度缺陷可能是由于与感觉运动失衡相关的运动命令中断、肩部刚度的微妙增加或激动剂激活减少所致。他们在指向左侧目标时较大的左侧偏差可能是由于右侧顶叶优势的增加，独立于头部转动/下颌旋转的方向，这扩大了左侧空间表征和/或增加了左侧空间注意力。这些缺陷可能会延伸到左脑跟踪和注视物体的能力，导致空间依赖性运动和认知能力的技能下降。