Adaptive Electrical Stimulation for Locomotor Retraining

描述（由申请人提供）：最近的研究表明，脊髓损伤后运动功能的功能恢复可以通过治疗师提供的被动帮助下，在跑步机上使用部分体重支持的背带进行重复的步行运动来增强。这种恢复背后的推测机制是脊髓和棘上中枢神经回路的活动依赖性可塑性。尽管一些受试者的结果令人鼓舞，但总的来说，从运动疗法中获得的功能增益是中等的，并且在受试者之间存在很大的差异。我们认为，这种治疗的“标准”形式（在治疗师的被动帮助下，跑步机/背带）是基于良好的运动学习原则的，但治疗的方式并没有使治疗效果最大化。我们建议运动疗法可以通过以下方式得到加强：1)产生更“生理性”的感觉运动模式，即包括适当的肌肉收缩，因此更类似于完整状态下的感觉运动模式；2)以更可重复的方式产生运动模式。我们的方法利用电刺激的自适应控制来激活肌肉，以便在跑步机上产生可重复的运动。我们相信，结合适当的时间收缩和可重复的运动模式将导致运动治疗的改进形式。此外，控制系统的自适应特性可以用来鼓励逐渐增加自主输入，从而提供一种机制，使个体在运动过程中摆脱fes的帮助。这项工作的长期目标是开发一个系统，将提供一个更有效和高效的形式的运动再训练治疗。在这项工作中，我们将开发一种技术，利用电刺激肌肉的自适应控制来产生具有协调的感觉运动活动模式的可重复的步进运动。该系统将使用经皮神经肌肉刺激来帮助在跑步机上行走时产生运动，并由安全带提供部分体重支持。自适应控制技术将用于为给定个体自动确定一组适当的刺激参数，并自动调整刺激参数以考虑疲劳和/或运动再训练的影响。拟议项目的目标是开发自适应系统并评估其产生特定运动模式的能力。我们将实施自适应系统，并通过实验证明，它能够可靠地使脊髓损伤患者在部分体重支持的跑步机上行走。在未来的工作中（超出本提案的范围），我们将比较适应性fes辅助运动疗法与其他形式的运动疗法的疗效。

DESCRIPTION (provided by applicant): Recent studies have indicated that functional recovery of locomotor function after spinal cord injury may be enhanced by performing repetitive stepping movements on a treadmill with a harness for partial body weight support with passive assistance provided by therapists. The putative mechanism that underlies this recovery is activity-dependent plasticity of neural circuits both in the spinal cord and in supraspinal centers. Although results in some subjects have been encouraging, in general, the functional gains that have been demonstrated from locomotor therapy are moderate and there is a high variability across subjects. We believe that the 'standard' form of this therapy (treadmill/harness with passive assistance from therapists) is soundly based on well established principles of motor learning, but the manner in which the therapy is delivered does not enable maximization of the therapeutic effect. We propose that locomotor therapy may be enhanced by: 1) producing sensorimotor patterns that are more 'physiological' - i.e. that include appropriately timed muscle contractions and are therefore more similar to sensorimotor patterns in the intact state and 2) generating movement patterns in a more repeatable manner. Our approach utilizes adaptive control of electrical stimulation to activate muscles in order to generate repeatable movements on the treadmill. We believe that the combination of appropriately timed contractions and repeatable movement patterns will result in an improved form of locomotor therapy. Furthermore, the adaptive nature of the control system may be used to encourage gradual increases in voluntary input, therefore providing a mechanism for weaning the individual from FES-assistance during locomotion. The long-term goal of this work is to develop a system that will provide a more effective and efficient form of locomotor retraining therapy. In this work, we will develop a technique that uses adaptive control of electrically-stimulated muscles to produce repeatable stepping movements with coordinated sensorimotor patterns of activity. The system will use transcutaneous neuromuscular stimulation to assist in movement generation while walking on the treadmill with partial body weight support provided by a harness. Adaptive control techniques will be used to automatically determine an appropriate set of stimulation parameters for a given individual and to automatically adjust the stimulation parameters to account for fatigue and/or motor retraining effects. The goals of the proposed project are to develop the adaptive system and to evaluate its ability to generate specified movement patterns. We will implement the adaptive system and experimentally demonstrate that it is capable of reliably producing stepping movements by individuals with spinal cord injury on a treadmill with partial body weight support. In future work (beyond the scope of this proposal), we will compare the efficacy of adaptive FES-assisted locomotor therapy with other forms of locomotor therapy.