Deficits in the coordination of multijoint arm movements in patients with hemiparesis: evidence for disturbed control of limb dynamics
Deficits in the coordination of multijoint arm movements in patients with hemiparesis: evidence for disturbed control of limb dynamics
复制标题
DOI：
10.1007/s002219900275
复制
发表时间：
2000-04-01
影响因子：
2
通讯作者：
Rymer, WZ
中科院分区：
文献类型：
--
作者：
Beer, RF;Dewald, JPA;Rymer, WZ
本研究详细分析了6例慢性偏瘫患者多关节手臂运动加速期的运动学和动力学障碍。对三名对照受试者的优势和非优势肢体的运动也进行了检查。受试者从一个中心起始点快速移动到16个等距离围绕圆周的目标。上肢的支撑是由气浮装置提供的，这种装置允许在水平面上进行非常低的摩擦运动。我们发现，患者保留了对目标方向做出反应的能力，即调整瘫痪肢体的初始运动方向。然而，与非瘫痪肢体或对照受试者相比，瘫痪肢体的运动被系统性地误导。反向动力学分析揭示了肘部肌肉扭矩的异常空间调谐，该扭矩用于启动瘫痪肢体的运动。根据肌电记录，肘部肌肉的初始激活也有类似的空间异常。我们认为，这些空间异常是肢体肌肉控制信号的系统性干扰所致，不能归因于先前已确定的机制，如虚弱、痉挛介导的约束或刻板印象的肌肉激活模式(肌肉协同作用)。相反，我们的运动动力学分析和仿真研究表明，空间异常与多关节运动中产生的被动相互作用力矩的前馈控制受损是一致的。这种受损的控制力被假设为反映了肢体动力学内部表征的退化，这种退化要么是脑损伤的主要结果，要么是由于停用而发生的继发性后果。(C)斯普林格--维拉格2000年。
This study provides a detailed analysis of disturbances in the kinematics and dynamics of the acceleration phase of multijoint arm movements in six patients with chronic hemiparesis. Movements of the dominant and nondominant limbs were also examined in three control subjects. Subjects performed rapid movements from a central starting point to 16 targets located equidistantly around the circumference of a circle. Support of the upper limb was provided by an air-bearing apparatus, which allowed very low friction movements in the horizontal plane. We found that patients retained the capacity to modulate, in response to target direction, the initial direction of movements performed with the paretic limb. However, in comparison to the nonparetic limb or control subjects, movements of the paretic limb were misdirected systematically. An inverse dynamics analysis revealed an abnormal spatial tuning of the muscle torque at the elbow used to initiate movements of the paretic limb. Based on electromyographic recordings, similar spatial abnormalities were also apparent in the initial activations of elbow muscles. We argue that these spatial abnormalities result from a systematic disturbance in the control signal to limb muscles that cannot be attributed to previously identified mechanisms such as weakness, spasticity mediated restraint, or stereotypic muscle activation patterns (muscle synergies). Instead, our analysis of movement dynamics and simulation studies demonstrate that the spatial abnormalities are consistent with an impaired feedforward control of the passive interaction torques which arise during multijoint movements. This impaired control is hypothesized to reflect a degradation of the internal representation of limb dynamics that occurs either as a primary consequence of brain injury or secondary to disuse. (C) Springer-Verlag 2000.