Dipietro Laura, Krebs Hermano I, Fasoli Susan E, Volpe Bruce T, Hogan Neville
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Cortex. 2009 Mar;45(3):318-24. doi: 10.1016/j.cortex.2008.02.008. Epub 2008 Jun 14.
Submovements are hypothesized to be discrete building blocks of human movement. Changes in their parameters appear to account for features observed in processes of motor learning and motor recovery from stroke. Our previous studies analyzed submovement changes in subjects recovering from stroke. Subjects were trained on point-to-point movements with the assistance of a rehabilitation robot as part of a stroke treatment protocol. Results suggested that recovery starts first by regaining the ability to generate submovements and then, over a longer time period, by reacquiring the means to combine submovements. Over recovery submovements became fewer, longer, and faster and such changes contributed to changes in movement smoothness. Taken together these results lent support to the theory that movement is produced via centrally generated submovements and that changes in submovements characterize recovery. More recently, we investigated generalization of training. We found that stroke subjects trained on point-to-point movements became progressively better able to draw circles, a task on which they had received no training. The goal of this paper was to further investigate the changes that occur in untrained movements during motor recovery from stroke. Specifically we wanted to test whether changes in smoothness and submovements also characterize untrained movements. We analyzed circle drawing movements performed by 47 chronic stroke subjects who underwent training on point-to-point movements over an 18-session robot-assisted therapy program. We found that during recovery the shapes drawn by subjects became not only closer to circles (a task not trained during therapy) but also smoother. Concurrently, submovements grew fewer, longer, and faster. These results are consistent with the theory that movement is produced via submovements and suggest that changes in smoothness and submovements might characterize and describe the process of motor recovery from stroke. Also, they are consistent with the idea that motor recovery after a stroke shares similar traits with motor learning.
子运动被假定为人类运动的离散组成部分。其参数的变化似乎可以解释在运动学习和中风后运动恢复过程中观察到的特征。我们之前的研究分析了中风恢复患者的子运动变化。作为中风治疗方案的一部分，患者在康复机器人的辅助下进行点对点运动训练。结果表明，恢复首先通过重新获得产生子运动的能力开始，然后在更长的时间段内，通过重新获得组合子运动的方式。在恢复过程中，子运动变得更少、更长且更快，这些变化导致了运动平滑度的改变。综合这些结果支持了这样一种理论，即运动是通过中枢产生的子运动产生的，并且子运动的变化表征了恢复过程。最近，我们研究了训练的泛化。我们发现，接受点对点运动训练的中风患者逐渐能够更好地画圆，而他们在这项任务上并未接受过训练。本文的目的是进一步研究中风运动恢复过程中未训练运动所发生的变化。具体来说，我们想测试平滑度和子运动的变化是否也表征未训练的运动。我们分析了47名慢性中风患者在18节机器人辅助治疗课程中接受点对点运动训练后所进行的画圆运动。我们发现，在恢复过程中，患者画出的形状不仅更接近圆形（这是治疗期间未训练的任务），而且更平滑。同时，子运动变得更少、更长且更快。这些结果与运动是通过子运动产生的理论一致，并表明平滑度和子运动的变化可能表征和描述中风后的运动恢复过程。此外，它们与中风后的运动恢复与运动学习具有相似特征的观点一致。
