ADAPTATION TO NOVEL FORCE FIELDS IN HEMIPARETIC STROKE

机器人机械手被视为潜在的重要康复工具，因为它们可以被编程为在受试者移动时施加各种力(力场)。它们还可以重复使用，同时监测和记录受试者的表现，允许进行比目前人类治疗师所能接受的更密集和更长时间的治疗。剩下的问题是，什么样的力场最适合帮助偏瘫受试者运动功能的恢复，中风幸存者应该如何在这样的力场中接受训练。当正常受试者暴露在一个新的力场中，以系统的方式干扰他们的运动时，他们会逐渐适应，因此当干扰力场意外移除时，他们会表现出特有的后遗症。最初的适应和后遗症都是在受试者没有意识到适应过程的情况下发生的。由于后遗症可以通过神经肌肉骨骼系统的动态模型来预测，我计划使用动态建模技术作为一种工具来设计力，从而在偏瘫中风患者中产生理想的后遗症，这些患者在运动中表现出刻板印象的错误。目前，有证据表明，偏瘫中风患者在经历辅助力场时，他们的康复会得到提高。其他证据表明，在伸展运动中针对阻力场进行训练，也可以帮助患者在阻力场被移除后进行理想的运动。这个项目的主要目标是确定哪种类型的场地--辅助场地或阻力场地--最适合达到理想的康复结果。为此，我将使用一个可编程的两连杆机器人，它在水平平面上移动时施力。我计划首先确定后遗症可以持续到什么程度。然后，我将开发和测试一个设计辅助力场和阻力力场的计算框架。最后，将确定辅助力场或阻力力场是否最适合于调节偏瘫中风幸存者的运动所需的代偿效应。这些实验结果将有利于利用机器人开发和应用更复杂的康复环境，并为机器人辅助康复领域更长期的临床试验提供明确的方向。

Robotic manipulators are seen as a potentially important instrument for rehabilitation because they can be programmed to exert a variety of forces (force fields) while the subject moves. They can also be used repetitively, while monitoring and recording subject's performance, allowing more intensive and prolonged treatment than is currently feasible with a human therapist. The question that remains is what type of force field is best suited for assisting in the recovery of motor function in hemiparetic human subjects, and how should the stroke survivor be trained in such a force field. When normal subjects are exposed to a novel force field that disturbs their motion in a systematic fashion, they adapt progressively so that they exhibit characteristic after-effects when the disturbing force field is unexpectedly removed. Both the initial adaptation and the after-effects occur without subjects being aware of the adaptive process. Since after-effects can be predicted by dynamic models of the neuro-musculoskeletal system, I plan to use dynamic modeling techniques as a tool for designing forces that will yield desirable after- effects in hemiparetic stroke patients that show stereotypical errors in movement. Currently there is evidence that hemiparetic stroke patients recovery is enhanced when they experience assistive force fields. Other evidence suggests that training against resistive force fields during reaching movements may also help the patient perform a desirable motion once the resistive field is removed. The main goal of this project is to determine which type of field -- assistive or resistive -- is best suited to attaining desirable rehabilitation outcomes. To this end I will use a programmable two-link robot that exerts forces during reaching movements in the horizontal plane. I plan to determine first to what extent after-affects can be made to persist. I will then develop and test a computational framework that designs assistive and resistive force fields. Finally will determine whether assistive or resistive force fields are best suited for mediating the desired compensatory effects on movements in hemiparetic stroke survivors. The results of these experiments should favor the development and application of more sophisticated rehabilitation environments using robots and provide a clear direction for more long-term clinical trials in the area of robot assisted rehabilitation.