The peripheral motor repertoire as a neuromuscular constraint on walking balance integrity in age-related falls risk

项目总结 尽管常规的诊断和康复努力，以及对站立平衡控制的丰富理解， 我们迅速老龄化的人口仍然处于极高的跌倒风险中。这其中的一个主要贡献者 持续存在的风险是，大多数跌倒发生在日常步行任务中，这些任务人们对此知之甚少，而且 需要更复杂的神经肌肉协调。我们的长期目标是引进一种新型的神经肌肉 年龄相关性步行平衡障碍的机制作为早期诊断测试的战略目标 预防和康复，以防止老年人跌倒。我们假设所有的个体都依赖于一个本金 每天要完成的外周神经肌肉指令的数量--一个“外周运动曲目” 在此过程中可能发生跌倒的步行任务(例如，步行、转身、步态启动、精确步法)。支撑点 通过有希望的试点数据，R21的目标是严格测试总体假设，即 用于日常步行任务的外周运动曲目代表了老年人的神经肌肉约束 成年人成功应对行走平衡扰动从而防止跌倒的能力 社区。这项横断面研究有三个目标。《特定目标1》将检验这一假设 用于完成日常行走任务的运动技能(即运动模块或肌肉协同作用的数量) 受跌倒病史的影响比单独按年龄减少更多，且与前一次跌倒次数呈负相关 年。具体目标2将量化外周运动曲目、功能平衡 正直，以及对未来跌倒的恐惧。在这里，我们将检验这样一个假设，即外围运动曲目的大小 在日常步行任务中使用，更多地与功能平衡的完整性有关，而不是对未来跌倒的恐惧。 我们将把这一发现解释为证据，表明外周运动曲目减少代表神经肌肉 与担心复发相关的紧急策略相比，导致糟糕的平衡控制的约束 瀑布。《特指目标3》将检验这样一种假设，即减少的外周运动技能与较大的 对感觉和机械平衡扰动范例的不同组合的敏感性在 走路。我们将把这一发现解释为所使用的外周运动曲目之间的关键机械联系 在日常步行任务和适应与社区跌倒相关的平衡挑战的能力。 这项拟议的研究是创新的，也是第一次结合：(1)最先进的肌电分析 在日常步行任务中，跌倒可能发生在年轻人和老年人中，无论有没有 跌倒史，(2)行走平衡完整性、平衡自我的功能和神经心理学测量 疗效和对未来跌倒的恐惧，以及(3)感觉和机械平衡扰动的组合 在行走过程中应用范例。该项目将提供对非常具体和创新的 神经肌肉控制的特征作为年龄相关性平衡障碍的一种机制，同时为 为预防跌倒而进行的更有效的诊断和康复目标的计划前瞻性研究。

PROJECT SUMMARY Despite conventional diagnostic and rehabilitative efforts, and a rich understanding of standing balance control, our rapidly aging population remains at an exceptionally high risk of debilitating falls. A major contributor to this continued risk is that most falls occur during everyday walking tasks which are much less well understood and require more complex neuromuscular coordination. Our long-term goal is to introduce a novel neuromuscular mechanism for age-associated walking balance impairment as a strategic target for diagnostic testing, earlier prevention, and rehabilitation to prevent falls in older adults. We posit that all individuals rely on a principal number of peripheral neuromuscular commands – a “peripheral motor repertoire” – to accomplish everyday walking tasks during which falls may occur (e.g., walking, turning, gait initiation, precision stepping). Supported by promising pilot data, the objective of this R21 is to rigorously test the overarching hypothesis that a reduced peripheral motor repertoire used for everyday walking tasks represents a neuromuscular constraint on older adults’ ability to successfully respond to walking balance perturbations and thereby prevent falls in the community. This cross-sectional study has three aims. Specific Aim 1 will test the hypothesis that the peripheral motor repertoire (i.e., number of motor modules or muscle synergies) used to accomplish everyday walking tasks is reduced by falls history more than by age alone and negatively correlates with the number falls in the prior year. Specific Aim 2 will quantify the association between the peripheral motor repertoire, functional balance integrity, and fear of future falls. Here, we will test the hypothesis that the size of the peripheral motor repertoire used during everyday walking tasks associates more with functional balance integrity than fear of future falls. We will interpret this finding as evidence that a reduced peripheral motor repertoire represents a neuromuscular constraint that precipitates poor balance control versus an emergent strategy associated with a fear of recurrent falls. Specific Aim 3 will test the hypothesis that a reduced peripheral motor repertoire associates with larger susceptibility to a diverse combination of sensory and mechanical balance perturbation paradigms applied during walking. We will interpret this finding as a critical mechanistic link between the peripheral motor repertoire used during everyday walking tasks and ability to accommodate balance challenges relevant to falls in the community. The proposed study is innovative, and the first to combine: (1) state-of-the-art electromyographic analyses across everyday walking tasks during which falls may occur in young adults and in older adults with and without a history of falls, (2) functional and neuropsychological measures of walking balance integrity, balance self- efficacy, and fear of future falls, and (3) a combination of sensory and mechanical balance perturbation paradigms applied during walking. This project will provide pivotal insight into a very specific and innovative feature of neuromuscular control as a mechanism for age-related balance impairment while paving the way for planned prospective studies toward more effective targets for diagnostics and rehabilitation to prevent falls.