Proactive and reactive perturbation training to reduce falls and improve gait stability in people with chronic stroke

项目总结/摘要 中风后，独立活动能力的缺陷是生活质量下降的主要原因， 许多患有慢性中风（PwCS）的人无法恢复到他们先前的活动水平 参与或融入社区。活动性缺陷的一个主要原因是步态不稳定， 增加了福尔斯跌倒的风险，限制了独立功能。虽然一些常见的康复方法（例如， 运动训练，传统的平衡训练，加强）可以改善某些方面的功能，他们有 未能解决PwCS中的跌倒发生率。在某种程度上，这种缺乏成功的情况可能是由于目前的干预措施 没有针对导致中风后步态不稳定的特定机制。 这项研究的一个长期目标是开发一个基于机制的干预工具箱，以改善各种 中风后的功能作为实现这一目标的一个步骤，本提案的目标是确定 是否有针对性的扰动训练可以通过改善步态稳定性来减少PwCS中的福尔斯。While微扰 训练以前曾用于降低其他临床人群的跌倒风险，迄今为止， 在普华永道这样做是不成功的。这种缺乏成功可能是由于所应用的 扰动，其传统上被设计为引起离散的反应性响应以避免失去平衡。 相比之下，本提案将应用旨在引起主动调整的机械扰动， 神经机械策略用于确保每一步的行走稳定性。这种主动扰动 可以更好地适合于防止固有运动误差，该固有运动误差是导致 PwCS之间的平衡和福尔斯。这项工作的中心假设是，与反应式方法不同， 主动扰动训练将重新训练广义步态稳定策略，降低福尔斯的风险。这 将通过三个具体目标来解决假设。 第一个具体目标是确定PwCS中的跌倒率是否通过主动或被动训练降低， 其对于可应用于真实的世界的干预的发展具有直接的临床意义。 第二个具体目标是描述神经力学机制，这些机制是步态变化的基础， 扰动训练，揭示了通常用于确保步行平衡的稳定策略 可以通过适当的目标扰动来加强。最后，第三个具体目标是确定 主动式或被动式训练是否能像理想的干预那样产生普遍的步态稳定， 甚至对在真实的世界行走中可能经历的未经训练的扰动也提高了弹性。 拟议的项目是基于双足步行控制的神经机械框架，因此允许 研究临床相关结局（跌倒率）和所用策略的机制指标， 确保稳定。该项目产生的知识有可能有助于发展 一个大规模的康复范例，解决中风后福尔斯的重要问题。

PROJECT SUMMARY / ABSTRACT Following a stroke, deficits in independent mobility are a primary contributor to decreased quality of life, as many people with chronic stroke (PwCS) are prevented from returning to their prior levels of activity participation or involvement in the community. A major cause of mobility deficits is gait instability, which can increase the risk of falls and limit independent function. While several common rehabilitation methods (e.g. locomotor training, traditional balance training, strengthening) can improve some aspects of function, they have failed to address fall incidence among PwCS. In part, this lack of success is likely due to current interventions not being targeted toward the specific mechanisms causing post-stroke gait instability. A long-term goal of this research is to develop a toolbox of mechanism-based interventions to improve various aspects of post-stroke function. As a step toward this goal, the objective of the present proposal is to determine whether targeted perturbation training can reduce falls in PwCS by improving gait stability. While perturbation training has previously been used to reduce fall risk in other clinical populations, it has thus far been unsuccessful at doing so among PwCS. This lack of success may be due to the nature of the applied perturbations, which are traditionally designed to elicit discrete Reactive responses to avoid a loss of balance. In contrast, the present proposal will apply mechanical perturbations designed to elicit Proactive adjustments in the neuromechanical strategies used to ensure walking stability with every step. Such Proactive perturbations may be better suited to prevent the intrinsic movement errors that are a primary contributor to losses of balance and falls among PwCS. The central hypothesis of this work is that that unlike Reactive methods, Proactive perturbation training will retrain generalized gait stabilization strategies, reducing the risk of falls. This hypothesis will be addressed through three Specific Aims. The first Specific Aim is to determine whether fall rate in PwCS is reduced by Proactive or Reactive training, with immediate clinical implications for the development of interventions that can be applied in the real world. The second Specific Aim is to characterize the neuromechanical mechanisms that underlie gait changes with perturbation training, revealing whether the stabilization strategies normally used to ensure walking balance can be strengthened with appropriately targeted perturbations. Finally, the third Specific Aim is to determine whether Proactive or Reactive training produces generalized gait stabilization, as an ideal intervention would improve resilience even to untrained perturbations that may be experienced in real world walking. The proposed project is based on a neuromechanical framework of bipedal walking control, and thus allows investigation of both clinically relevant outcomes (fall rate) and mechanistic measures of the strategies used to ensure stability. The knowledge resulting from this project has the potential to contribute to the development of a larger-scale rehabilitation paradigm addressing the important problem of post-stroke falls.