Laczko Jozsef, Scheidt Robert A, Simo Lucia S, Piovesan Davide
IEEE Trans Neural Syst Rehabil Eng. 2017 Jul;25(7):798-810. doi: 10.1109/TNSRE.2017.2652393. Epub 2017 Jan 16.
It is well documented that neurological deficits after stroke can disrupt motor control processes that affect the smoothness of reaching movements. The smoothness of hand trajectories during multi-joint reaching depends on shoulder and elbow joint angular velocities and their successive derivatives as well as on the instantaneous arm configuration and its rate of change. Right-handed survivors of unilateral hemiparetic stroke and neurologically-intact control participants held the handle of a two-joint robot and made horizontal planar reaching movements. We decomposed endpoint jerk into components related to shoulder and elbow joint angular velocity, acceleration, and jerk. We observed an abnormal decomposition pattern in the most severely impaired stroke survivors consistent with deficits of inter-joint coordination. We then used numerical simulations of reaching movements to test whether the specific pattern of inter-joint coordination deficits observed experimentally could be explained by either a general increase in motor noise related to weakness or by an impaired ability to compensate for multi-joint interaction torque. Simulation results suggest that observed deficits in movement smoothness after stroke more likely reflect an impaired ability to compensate for multi-joint interaction torques rather than the mere presence of elevated motor noise.
有充分的文献记载，中风后的神经功能缺损会扰乱影响伸手动作流畅性的运动控制过程。多关节伸手时手部轨迹的流畅性取决于肩部和肘关节的角速度及其连续导数，以及手臂的瞬时构型及其变化率。单侧偏瘫性中风的右利手幸存者和神经功能正常的对照参与者握住双关节机器人的手柄，进行水平平面的伸手动作。我们将终点急动度分解为与肩部和肘关节角速度、加速度和急动度相关的分量。我们在受损最严重的中风幸存者中观察到一种异常的分解模式，这与关节间协调缺陷一致。然后，我们使用伸手动作的数值模拟来测试实验中观察到的关节间协调缺陷的特定模式是否可以用与无力相关的运动噪声普遍增加或补偿多关节相互作用扭矩的能力受损来解释。模拟结果表明，中风后观察到的运动流畅性缺陷更可能反映了补偿多关节相互作用扭矩的能力受损，而不仅仅是运动噪声升高。
