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在治疗师提供的被动辅助下在跑步机上进行重复的步进运动来增强，跑步机上有用于部分体重支撑的背带。这种恢复的假定机制是脊髓和脊髓上中枢神经回路的活动依赖性可塑性。虽然在一些受试者中的结果是令人鼓舞的，但一般来说，从运动疗法中证明的功能增益是中等的，并且在受试者之间存在高度变异性。我们认为，这种治疗的“标准”形式（治疗师被动辅助的跑步机/背带）是基于运动学习的既定原则，但治疗的方式并不能使治疗效果最大化。我们提出，运动疗法可以通过以下方式来增强：1）产生更“生理”的感觉运动模式，即包括适当定时的肌肉收缩，因此与完整状态下的感觉运动模式更相似，以及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，结合适当的定时收缩和可重复的运动模式将导致运动疗法的改进形式。此外，控制系统的自适应性质可以用于鼓励自愿输入的逐渐增加，因此提供了用于在运动期间使个体脱离FES辅助的机制。这项工作的长期目标是开发一种系统，提供一种更有效和更高效的运动再训练疗法。在这项工作中，我们将开发一种技术，使用电刺激肌肉的自适应控制，以产生可重复的步进运动与协调的感觉运动模式的活动。该系统将使用经皮神经肌肉刺激来辅助运动生成，同时在跑步机上行走，并通过安全带提供部分体重支撑。自适应控制技术将用于自动确定给定个体的一组适当的刺激参数，并自动调整刺激参数以考虑疲劳和/或运动再训练效应。拟议项目的目标是开发自适应系统，并评估其产生指定的运动模式的能力。我们将实施的自适应系统和实验证明，它是能够可靠地产生步进运动的个人脊髓损伤的跑步机上与部分体重的支持。在未来的工作中（超出本提案的范围），我们将比较自适应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.