Exploiting Selective Recruitment to Prolong Standing after SCI

描述（由申请人提供）： 该项目的目标是整合几种已证明的技术，用于恢复脊髓损伤（SCI）瘫痪后的下肢功能，并研究旨在最大限度地减少站立期间膝伸肌肌肉组织疲劳的新型刺激方案。所有现有的用于SCI后站立的刺激系统都依赖于膝伸肌的持续激活，这导致快速疲劳，从而限制了它们的功能和临床实用性。的 这项转化研究的主要目的是通过开发和实施先进的刺激范例来提高站立用神经假体的性能，该范例利用多触点外周神经电极的选择性来延长站立持续时间。 用于利用多个协同肌纤维群的选择性激活的方法包括在独立组之间交替以减少刺激占空比，交错刺激脉冲以减少局部刺激频率，以及先前未探索的范例，其中由每个群产生的正弦力的振荡产生超过任何单独贡献的恒定净输出。 目前还没有一个成功的关键评价这些方法中的任何长期在人类，这仍然需要严格的实验室测试。稳定和选择性的外周神经接口（多触点螺旋袖电极）最近已可用于长期人体植入，并将使SCI患者的高级刺激范例的临床评估成为可能。我们将在植入站立式神经假体的接受者中实施每种范例，并确定其在膝关节伸展力矩、耐力、稳健性和经过的站立时间方面的相对益处。需要为每个肌纤维群体调整的众多参数目前是在耗时的试错过程中临时选择的。 我们将进行一系列慢性动物研究，以开发和测试自动化方法，用于调整每个刺激范式并选择最佳参数，以最大限度地提高性能，并将其推广到其他神经接口技术。 这些研究所产生的调整和优化方法将在临床上与各种植入式神经假体的用户进行验证，并最终适用于转移到其他临床应用。

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.