Brain and Behavioral Responses to Backward Walking Training Post-Stroke

背景/目的：脑卒中后步行的物理康复旨在改善个人的活动能力 在运动、感觉和平衡障碍的情况下。有效的战略，以改善平衡和 降低跌倒风险仍然是中风康复的需要。为了解决这个问题，我们的实验室研究了一种 一种新颖的向后行走训练计划（BW训练），以提高向前和向后行走的速度 以及急性和慢性中风患者的平衡。我们先前发表的工作 证明了这种干预是安全的，可行的和有效的，然而，关键的问题仍然存在 关于如何最好地提供这种干预措施以取得最佳效果的问题没有得到答复。这项建议的主要目的是 是建立BW训练的剂量效应，以最大限度地提高前向行走速度、后向行走速度 速度和动态平衡。此外，我们将确定基线脑MRI预测反应， BW训练干预和探索大脑活动的变化，作为这种行为干预的结果。我们 有兴趣了解大脑结构和功能测量中的个体差异如何可能 区分对BW训练的反应。这一信息将促进审慎决策， 哪些患者适合进行这种新的干预。我们将进行随机对照试验 有三个具体的目的来测试1）BW训练阶段对步行速度的剂量效应， 平衡，2）特定脑区之间的静息状态功能连接（rs-FC）的能力， 基于任务的功能磁共振成像中脑感兴趣区的血氧水平依赖性激活 预测BW训练结果和3）在对侧踝关节期间rs-FC和BOLD激活的变化 与基线相比，BW训练干预后的运动。 研究设计：这是一项随机单盲对照试验。 受试者：48名卒中后2-4个月的受试者将符合以下研究标准：1）非卧床 步态速度< 0.8 m/s; 2）社区居住; 3）贝格平衡量表< 42; 4）无其他 神经系统疾病; 5）稳定的心脏状态; 6）无下肢矫形损伤或疼痛 限制步态能力; 7）不存在金属和磁共振敏感的植入式医疗装置。 方法：在基线评估A之后，参与者将被随机分配到18或27个阶段 BW训练组。BW训练干预（每周3次，持续6或9周）包括20-30分钟的步骤 使用体重支撑和跑步机系统进行训练，然后进行20分钟的地上步态训练。 评估B将在每组最后一次培训后进行。评估C将在- 两组在干预后6个月进行干预和评估D。磁共振成像 在踝关节运动任务期间，将评估ROI中由rs-FC和BOLD血流组成的大脑的 评估A和B分别针对具体目标2和具体目标3。 结果测量：主要结果测量是向前步态速度。次要措施包括落后 步行步态速度、通过功能性步态评估和质心测量的动态平衡 不对称性、跌倒自我效能与时空步态测量。 数据分析计划：样本量为48（24/组），可提供80%的统计功效来检测0.11 m/s 在5%的显著性水平下，18次和27次治疗组之间的干预后步态速度差异 使用双样本t检验。为了评估训练剂量效应，将对主要受试者进行双样本t检验。 结果，向前行走速度。干预前rs-FC和BOLD激活ROI的能力 将基于与步态速度变化的相关性来评估预测干预反应。是说 将比较每个网络的连接强度和每个ROI的平均信号强度， 干预后。

Background/Purpose: Physical rehabilitation of walking post-stroke is designed to improve individuals' mobility in the presence of motor, sensory and balance impairments. Effective strategies to improve balance and decrease fall risk continue to be a need in stroke rehabilitation. To address this, our laboratory has studied a novel Backward Walking Training program (BWTraining) to improve both forward and backward walking speed as well as balance in individuals with both acute and chronic stroke. Our prior published work has demonstrated that this intervention is safe, feasible and effective, however, critical questions remain unanswered regarding how best to deliver this intervention for optimal impact. The primary aim of this proposal is to establish dosage effects of BWTraining for maximizing gains in forward walking speed, backward walking speed, and dynamic balance. Additionally, we will determine baseline brain MRI predictors of response to BWTraining intervention and explore changes in brain activity as a result of this behavioral intervention. We are interested in understanding how individual differences in structural and functional brain measurements might distinguish between responses to BWTraining. This information will promote prudent decision-making as to which patients are good candidates for this novel intervention. We will conduct a randomized controlled trial with three specific aims to test the 1) Dose effect of number of BWTraining sessions on walking speed and balance, 2) the ability of resting state Functional Connectivity (rs-FC) between specified brain regions and Blood Oxygen Level-Dependent (BOLD) activation of brain Regions Of Interest (ROIs) during task-based fMRI to predict BWTraining outcomes and 3) changes in both rs-FC and BOLD activation during contralateral ankle motion following BWTraining intervention compared to baseline. Study Design: This is a randomized single-blind controlled trial. Subjects: Forty-eight individuals, 2-4 months post-stroke, will meet the following study criteria: 1) ambulatory with gait speed < 0.8 m/s; 2) community-dwelling; 3) Berg Balance Scale < 42; 4) absence of other neurological conditions; 5) stable cardiac status; 6) absence of lower extremity orthopedic impairments or pain that limits gait ability; 7) absence of metal and Magnetic Resonance sensitive implanted medical devices. Methods: Following baseline Assessment A, participants will be randomized to an 18 or 27 session BWTraining group. BWTraining intervention (3X/week for 6 or 9 weeks) consists of 20–30 minutes of step training using a Body Weight Support and Treadmill system followed by 20 minutes of overground gait training. Assessment B will occur after the final training session for each group. Assessment C will occur 6-weeks post- intervention and Assessment D at six months post-intervention for both groups. Magnetic Resonance Imaging of the brain consisting of rs-FC and BOLD blood flow in ROI's during an ankle motor task will be assessed at Assessments A and B to address Specific Aim 2 and Specific Aim 3 respectively. Outcome Measures: Primary outcome measure is forward gait speed. Secondary measures include backward walking gait speed, dynamic balance measured by the Functional Gait Assessment and Center of Mass Asymmetry, fall self-efficacy and spatial-temporal gait measures. Data Analysis Plan: A sample size of 48 (24/group) provides 80% statistical power to detect a 0.11 m/s difference in post-intervention gait speed between the 18- and 27-session groups at a 5% significance level using a two-sample t-test. To assess training dose effect, a two-sample t-test will be performed on the primary outcome, forward walking speed. The ability of rs-FC and BOLD activation of ROI's conducted pre-intervention to predict intervention response will be assessed based on the correlation with gait speed change. Mean connectivity strength for each network and mean signal intensity strength for each ROI will be compared pre- to post-intervention.