Spinal root stimulation for restoration of function in lower-limb amputees

项目总结 最近在设计和驱动方面的进步导致了假肢的重大改进。然而，这些设备 缺乏提供直接感觉反馈的手段，需要用户根据压力推断肢体状态信息 残肢。缺乏知觉限制了他们控制假肢的能力，并导致步态缓慢和风险增加。 坠落。也有证据表明，缺乏感觉反馈会导致幻肢疼痛(PLP)，而电刺激 刺激背根神经节(DRG)可降低PLP。这项研究的主要目标是将其用于商业 现有的FDA批准的脊髓刺激器(SCS)可用于测试电刺激背根神经节和背部的效果 作为恢复自然感觉(如压力、运动)、减少PLP和改善步态的一种手段 胫骨截肢者的功能。我们将使用刺激来(1)产生压力感和关节活动，(2) 减少PLP，(3)唤起肌肉活动模式，模仿站立时正常发生的自动反应 行走，以及(4)改善站立和使用感应式假肢行走时的姿势稳定性。 目标1：刺激DRG/DR产生自然的压力感和关节活动，局部 到截肢，并实现临床上相关的减少幻肢疼痛 为了提供直观的反馈，唤起的感觉应该被认为起源于截肢，并应该感觉到 自然主义。随之而来的PLP降低也可能对生活质量产生重要影响。我们将进行详细的表演 当研究参与者被要求报告信息时，刺激参数变化的心理物理测试 关于诱发的感觉(如位置、形态、自然度)及其对PLP的影响。 目的：研究DRG/DR刺激对正常和截肢肢体运动反应的影响。 它们与刺激参数的关系 双边协调的反应在应对意外的干扰时起着重要的作用，比如滑倒和绊倒。 此外，步态各阶段之间的转换在很大程度上是由对来自 腿。为了使假肢在站立和行走时恢复截肢的全部功能，唤起 而精确控制这些反射性活动模式将是至关重要的。我们将记录肌电(EMG)信号 从四肢在站立和行走时不同的刺激模式和量化之间的关系 刺激参数和诱发的反射反应。了解这些关系将有助于规划 功能性假体使用的刺激模式。 目标3：通过刺激DRG/DR提供感觉反馈，减少姿势摆动，增加步态稳定性 为了量化感觉恢复对假肢使用的功能影响，我们将测量每位参与者的 带有压敏鞋垫和关节角度传感器的假肢，并使用这些设备的信号来调制 刺激。我们将进行一系列体位和平衡测量，并跟踪功能性假体的变化 该设备经过7天的带回家试用后使用。

PROJECT SUMMARY Recent advances in design and actuation have led to important improvements in prosthetic limbs. However, these devices lack a means for providing direct sensory feedback, requiring users to infer information about limb state from pressure on the residual limb. Lack of sensation limits their ability to control the prosthesis and leads to slow gait and increased risk of falling. There is also evidence that lack of sensory feedback contributes to phantom limb pain (PLP), and that electrical stimulation at the dorsal root ganglia (DRG) can reduce PLP. The primary objective of this study is to use commercially available, FDA-cleared spinal cord stimulator (SCS) leads to test the effects of electrical stimulation of the DRG and dorsal rootlets (DR) as a means of restoring naturalistic sensation (e.g. pressure, movement), reducing PLP, and improving gait function in transtibial amputees. We will use stimulation to (1) produce sensations of pressure and joint movement, (2) reduce PLP, (3) evoke patterns of muscle activity that mimic automatic responses that occur normally during standing and walking, and (4) improve postural stability when standing and walking with a sensorized prosthesis. Aim 1: Use stimulation of the DRG/DR to generate naturalistic sensations of pressure and joint movement, localized to the amputated limb, and achieve a clinically relevant reduction in phantom limb pain To provide intuitive feedback, evoked sensations should be perceived as originating in the amputated limb and should feel naturalistic. A concomitant reduction in PLP may also have important effects on quality of life. We will perform detailed psychophysical testing in which stimulation parameters are varied while study participants are asked to report information about the evoked sensation (e.g. location, modality, naturalness) and the effects on PLP. Aim 2: Characterize the motor responses in the intact and amputated limbs evoked by DRG/DR stimulation and their relationship to stimulation parameters Bilaterally coordinated reflexes play an important role when responding to unexpected perturbations like slips and trips. Additionally, the transitions between phases of gait are largely mediated by reflexive responses to sensory input from the legs. For a prosthesis to restore the full capabilities of the amputated limb during standing and walking, the ability to evoke and precisely control these patterns of reflexive activity will be critical. We will record electromyogram (EMG) signals from the limbs during standing and walking while varying stimulus patterns and quantify the relationships between stimulation parameters and evoked reflexive responses. Understanding these relationships will aide in the programming of stimulation patterns for functional prosthesis use. Aim 3: Decrease postural sway and increase gait stability by providing sensory feedback via DRG/DR stimulation To quantify the functional impact of sensory restoration on prosthetic limb usage, we will instrument each participant’s prosthetic limb with a pressure sensitive insole and joint angle sensors, and use signals from these devices to modulate stimulation. We will perform a battery of posture and balance measures, and we will track changes in functional prosthesis usage after a 7-day take-home trial of the device.