Exploiting Selective Recruitment to Prolong Standing after SCI

描述(由申请人提供)： 该项目的目标是集成几种已演示的技术，以恢复脊髓损伤(SCI)瘫痪后的下肢功能，并研究旨在将站立时膝关节伸肌疲劳降至最低的新刺激方案。所有现有的SCI后站立刺激系统都依赖于膝关节伸肌的持续激活，这会导致快速疲劳，限制了它们的功能和临床应用。这个 这项翻译研究的主要目的是通过开发和实施先进的刺激范例，利用多接触周围神经电极的选择性来延长站立时间，从而提高站立神经假体的性能。利用多个协同肌肉纤维群体的选择性激活的策略包括在独立群体之间交替以减少刺激占空比，交错刺激脉冲以降低局部刺激频率，以及以前未探索的范例，其中每个群体产生的正弦力的振荡产生超过任何个体贡献的恒定净输出。目前还没有对这些方法中的任何一种长期在人类身上进行成功的批判性评估，这些方法仍然需要严格的台架测试。稳定和选择性的周围神经接口(多接触螺旋袖套电极)最近已可用于慢性人体植入，并将使临床评估先进的刺激范例的个人脊髓损伤。我们将在植入站立式神经假体的接受者中实施每种范例，并根据膝关节伸展力矩、耐力、健壮性和站立时间来确定它们的相对益处。需要为每个肌肉纤维群体调整的许多参数目前是在耗时的反复试验过程中特别选择的。我们将进行一系列慢性动物研究，以开发和测试自动方法来调整每个刺激范例并选择最佳参数以最大化性能，并将其推广到其他神经接口技术。这些研究得出的调整和优化方法将在临床上得到各种植入神经假体的使用者的验证，并最终适用于其他临床应用。

DESCRIPTION (provided by applicant): The goal of this project is to integrate several demonstrated technologies for restoring lower limb function after paralysis from spinal cord injury (SCI), and examine novel stimulation schemes designed to minimize fatigue of the knee extensor musculature during standing. All existing stimulation systems for standing after SCI rely on continuous activation of the knee extensors, which results in rapid fatigue that limits their functionality and clinical utility. The primary objective of this translational study is to improve the performance of neuroprostheses for standing by developing and implementing advanced stimulation paradigms that exploit the selectivity of multi- contact peripheral nerve electrodes to prolong standing duration. Strategie for exploiting the selective activation of multiple synergistic muscle fiber populations include alternating between independent groups to reduce stimulus duty cycle, interleaving stimulus pulses to reduce local stimulus frequency, and a previously unexplored paradigm in which the oscillations of sinusoidal forces generated by each population produce a constant net output that exceeds any individual contribution. There has yet to be a successful critical evaluation of any of these methods chronically in humans, which still require rigorous bench testing. Stable and selective peripheral nerve interfaces (multi-contact spiral cuff electrodes) have recently become available for chronic human implantation and will enable the clinical assessment of advanced stimulation paradigms in individuals with SCI. We will implement each paradigm in recipients of implanted standing neuroprostheses and determine their relative benefits in terms of knee extension moment, endurance, robustness and elapsed standing duration. The numerous parameters that need to be adjusted for each muscle fiber population are currently selected ad hoc in a time consuming trial-and-error process. We will perform a series of chronic animal studies to develop and test automated methods for tuning each stimulation paradigm and selecting optimal parameters to maximize performance and generalize them to other neural interface technologies. The resulting tuning and optimization methods resulting from these studies will be verified clinically with users of a variety of implanted neuroprostheses, and will ultimately be suitable for transfer to other clinical applications.