Individual-specific engagement of cortical resources for standing balance control in aging and post stroke

项目摘要 我们的长期目标是确定健康和受损平衡的神经机制，以机械地指导- 基于预测，评估和干预措施，以解决老龄化中常见的平衡和步态障碍 和神经系统疾病。在临床上众所周知，平衡控制中皮质资源的参与 是老年人（包括中风幸存者）跌倒风险的指标，可通过平衡能力下降来推断 和/或当并发认知任务将注意力从平衡控制转移时的步态表现。科学 改善平衡障碍的预后工具、预防策略和干预措施的障碍是， 缺乏对皮质资源如何以及何时参与平衡控制的理解，特别是 平衡任务难度。我们的建议的一个创新是确定直接的，机械的措施，皮层 反应平衡期间的活动。我们将结合联合收割机MPI Ting在反应性神经力学方面的专业知识 平衡控制和MPI Borich在人类电生理学方面的专业知识，以确定大脑之间的关系， 活动和运动功能，以改善中风康复。我们的目标是识别大脑皮层的活动特征 区分个体、任务和群体水平的皮质资源参与平衡的差异 控制年轻人（目标1）、老年人（目标2）和因卒中导致单侧病变的老年人 (Aim 3）。我们将测量脑电图（EEG），肌电图（EMG）和生物力学信号 在反应平衡恢复到支撑表面平移期间。我们建议使用临床上可行的 基于电极的分析方法，以及机械上重要的解剖学信息功能 使用高密度EEG结合结构和功能MRI扫描进行分析。我们假设 在平衡控制期间，皮质活动特征以个体、年龄和疾病特异性方式增加 随着平衡任务难度的增加。在组内，我们预测皮质活动的个体差异是 平衡挑战，即，平衡任务难度标准化为步长阈值，衡量平衡的一个指标 功能然而，在两组之间，我们预测皮质活动特征及其与平衡挑战的关系。 会有所不同。我们的目标是由我们的初步数据，显示1）增加N1和β功率超过 平衡任务困难的腿部感觉运动区域取决于年轻人和老年人的平衡功能 感觉运动功能连接和平衡任务难度之间的相反关系， 老年人; 3）与感觉运动与前额叶运动相关的平衡功能的不同方面 老年人的感觉运动功能连接; 4）中风幸存者的感觉运动功能连接， 行走功能如果成功，我们将确定平衡健康的神经生理指标， 适用于整个生命周期，以及神经和骨科平衡障碍， 推进科学框架，实现个性化、机械化的精准医疗策略 评估和干预措施，以改善生活质量的平衡健康差。

Project Summary Our long-term goal is to identify neural mechanisms of healthy and impaired balance to guide mechanistically- based predictors, assessments, and interventions for addressing balance and gait impairments common in aging and neurological disorders. It is well-known clinically that engagement of cortical resources in balance control is an indicator of fall risk in older adults including stroke survivors, as inferred by the degradation of balance and/or gait performance when a concurrent cognitive task shifts attention away from balance control. A scientific barrier to improving prognostic tools, preventive strategies, and interventions for balance impairments is that we lack an understanding of how and when cortical resources are engaged in balance control, particularly with balance task difficulty. An innovation of our proposal is to identify direct, mechanistic measures of cortical activity during reactive balance. We will combine MPI Ting’s expertise in the neuromechanics of reactive balance control and MPI Borich’s expertise in human electrophysiology to identify relationships between brain activity and motor function to improve stroke rehabilitation. Our objective is to identify cortical activity signatures that distinguish individual-, task-, and group-level differences in the engagement of cortical resources for balance control amongst young adults (Aim 1), older adults (Aim 2), and older adults with unilateral lesions due to stroke (Aim 3). We will measure electroencephalographic (EEG), electromyographic (EMG), and biomechanical signals during reactive balance recovery to support-surface translations. We propose to use both clinically feasible electrode-based analysis approaches, as well as mechanistically-important anatomically-informed functional analyses using high-density EEG in combination with structural and functional MRI scans. We hypothesize that cortical activity signatures during balance control increase in an individual-, age-, and disease-specific manner as balance task difficulty increases. Within groups, we predict individual variability in cortical activity to be explained by balance challenge, i.e., balance task difficulty normalized to step threshold, a measure of balance function. However, between groups, we predict cortical activity signatures and their relation to balance challenge will differ. Our Aims are motivated by our preliminary data that show 1) increases in N1 and beta power over leg sensorimotor regions with balance task difficulty depend on balance function in young and older adults 2) opposite relationships between sensorimotor functional connectivity and balance task difficulty in younger vs. older adults; 3) distinct aspects of balance function associated with sensorimotor vs. prefrontal-motor connectivity in older adults; and 4) sensorimotor functional connectivity in stroke survivors associated with walking function. If successful, we will identify neurophysiological indicators of balance health that will be broadly applicable across the lifespan, and across neurological and orthopedic balance disorders to significantly advance the scientific framework to enable precision-medicine strategies for personalized, mechanistic assessments and interventions to improve quality of life those with poor balance health.