Multisensory augmentation to improve the standing balance of people with chronic stroke

中风后，站立平衡控制的缺陷导致生活质量下降， 功能活动性和增加的福尔斯风险。不幸的是，成功的康复方法 降低老年人的跌倒发生率（例如，有针对性的加强演习，扰动训练）尚未 在慢性中风（PwCS）患者中显示出相同的益处。这种不成功的部分原因可能是 这些干预措施不包括针对导致损失的躯体感觉缺陷的成分 平衡，在PwCS中很常见。 本提案的目的是设计一种新的多感觉增强方法，以改善控制 在PwCS中的站立平衡。随着感觉增强，人工反馈为神经系统提供了 关于身体动态的信息，可用于防止失去平衡。等 已经使用了一些方法来改善具有前庭缺陷的个体之间的平衡，主要是通过应用 提供有关身体摇摆信息的躯干振动刺激。然而，三个主要障碍 阻碍了在PwCS中有效使用这种方法。首先，这些方法依赖于认知处理 解释和回应反馈的新来源，而许多PwCS有认知缺陷。第二、 对单一来源的增强反馈的关注并不能解释如何 PwCS对感觉刺激有反应。最后，目前还不清楚感觉增强是否会 更有效地应用于PwCS作为培训工具（即，在康复期间暂时使用）或作为 辅助工具（即，在社区日常活动期间佩戴的设备）。拟议的研究将涉及 这些障碍中的每一个，都围绕着这样一个假设，即针对躯体感觉增强， 对个体患者最有用的反馈源将改善中风后平衡性能。 这一假设将通过三个具体目标来解决。 第一个具体目标是表征增强感觉反馈的平衡性能变化 在PwCS中。将增强四种不同的体感反馈源（躯干触觉、髋关节 本体感觉、脚踝本体感觉、足底皮肤感觉），其中每一个都可以有助于控制 内外平衡每种类型的增强的相对有效性将被量化为个人 参与者，以及从短暂的感官扰动预测这种有效性的能力-这将是 在快速确定适当的增强方法方面具有很大价值。第二个目标是评估 多感官增强的人在回路优化的可行性和有效性。鉴于 许多来源的感官反馈，可以有助于平衡控制，这种使用新的优化 确定最佳刺激范例以改善个体平衡的方法将增加 感觉增强的可能性具有重要的临床影响。第三个具体目标是确定 多感觉增强是否能持续改善平衡， 培训设备或辅助设备。这里，两种训练效果（例如，改善平衡， 不应用增强）和辅助效果（例如，长期以来不断改善平衡， 将在为期10周的干预过程中进行评估。 该项目在感觉运动平衡控制的神经生理学方面具有基础， 基于先前严格的基础科学研究的感官增强方法。这种方法将 从而进一步加深了该领域对感觉反馈和平衡之间关系的理解， 同时增加了对以下重要问题提供临床相关见解的可能性： 中风后平衡缺陷。

After a stroke, deficits in the control of standing balance contribute to a decreased quality of life, decreased functional mobility, and an increased risk of falls. Unfortunately, rehabilitation methods that have successfully reduced fall incidence in older adults (e.g., targeted strengthening exercises, perturbation training) have not yet shown the same benefits among people with chronic stroke (PwCS). This lack of success is likely due in part to these interventions not including a component that targets the somatosensory deficits that contribute to losses of balance and are quite common among PwCS. The objective of this proposal is to design a novel multisensory augmentation approach to improve the control of standing balance in PwCS. With sensory augmentation, artificial feedback provides the nervous system with information about the dynamic state of the body, which can be used to prevent losses of balance. Such methods have been used to improve balance among individuals with vestibular deficits, primarily by applying vibratory stimuli to the trunk that provide information about body sway. However, three primary barriers have prevented the effective use of this approach among PwCS. First, these methods rely on cognitive processing to interpret and respond to the novel source of feedback, while many PwCS have cognitive deficits. Second, the focus on a single source of augmented feedback does not account for the extensive variability in how PwCS respond to sensory stimulation. Finally, it is presently unclear whether sensory augmentation would be more effectively applied among PwCS as a training tool (i.e., used temporarily during rehabilitation) or as an assistive tool (i.e., a device worn during daily activities in the community). The proposed study will address each of these barriers, centered around the hypothesis that targeting somatosensory augmentation toward the feedback sources that are most useful for an individual patient will improve post-stroke balance performance. This hypothesis will be addressed through three Specific Aims. The first Specific Aim is to characterize changes in balance performance with augmented sensory feedback among PwCS. Four distinct sources of somatosensory feedback will be augmented (trunk tactile sense, hip proprioception, ankle proprioception, foot sole cutaneous sense), each of which can contribute to the control of mediolateral balance. The relative effectiveness of each type of augmentation will be quantified for individual participants, as will the ability to predict this effectiveness from brief sensory perturbations – which would be of great value in quickly identifying an appropriate augmentation approach. The second Specific Aim is to assess the feasibility and effectiveness of human-in-the-loop optimization of multisensory augmentation. Given the many sources of sensory feedback that can contribute to balance control, this use of novel optimization methods to identify the best stimulation paradigm to improve an individual’s balance would increase the likelihood of sensory augmentation having an important clinical impact. The third Specific Aim is to determine whether multisensory augmentation produces sustained balance improvements when applied as either a training device or as an assistive device. Here, both training effects (e.g., improved balance when augmentation is not applied) and assistive effects (e.g., continuously improved balance over long periods of augmentation) will be assessed over the course of a 10-week intervention. The proposed project has a foundation in the neurophysiology of sensorimotor balance control, applying sensory augmentation methods that are based on prior rigorous basic science research. This approach will thus further the field’s understanding of the relationship between sensory feedback and balance, while simultaneously increasing the probability of providing clinically relevant insight into the important problem of post-stroke balance deficits.