Muscle Morphology, Strength and Compensatory Strategies Following Stroke

描述（由申请人提供）：中风是导致成人长期残疾的主要原因。由于肌肉激活的时间和幅度异常，以及肌肉发力能力的改变，步态的表现被打乱，并出现不对称的运动学和动力学。建议的工作将调查中风后改变的肌肉形态，肌肉激活和肌肉协调之间的关系。我们的技术目标包括开发和实现工具，以促进使用Simbios研究人员介绍的SimTK框架创建特定主题的人体运动模拟。我们建议通过实现以下具体目标，应用该模拟工具包来了解中风后偏瘫的肌肉协调：(1)确定慢性卒中患者麻痹性和非麻痹性肌肉的形态学特征及其与年龄匹配的健康受试者的差异；(2)确定卒中后肌肉力量和关节净扭矩的减少是否由于形态学改变或激活受损所致；(3)确定限制卒中后人群步态速度的因素；(4)确定健康人与卒中后人群自我选择和最快可能的步态速度之间的差异。在提出的一系列研究中，静态MRI将用于评估下肢关键肌肉的生理横截面积。肌肉活动和净关节扭矩的测量将在一系列等距和等速测力计任务中进行。将收集健康和中风后个体的实验步态数据，并用于生成受试者特定的模拟。将采用各种分析技术来评估组间的差异，例如肌肉兴奋模式、肢体结构和肌肉力对关节加速度的潜在影响，并解决临床相关的假设。公共卫生相关性：中风是导致成人长期残疾的主要原因。中风后步行时肌肉发力能力、激活和协调的改变之间的关系尚不清楚。通过耦合实验和模拟，我们可以确定限制中风后步态速度的因素，并协助康复专业人员设计针对个体受试者特定损伤的治疗干预措施。

DESCRIPTION (provided by applicant): Stroke is a leading cause of long-term adult disability. Due to abnormal timing and magnitude of muscle activation, and altered muscle force generating capacity, performance of gait is disrupted and asymmetric kinematics and kinetics emerge. The proposed work will investigate the relationship between altered muscle morphology, muscle activation, and muscle coordination following stroke. Our technical objectives include the development and implementation of tools to facilitate the creation of subject-specific simulations of human movement using the SimTK framework introduced by the Simbios investigators. We propose to apply this simulation toolkit to understand muscle coordination in post-stroke hemiparesis by achieving the following specific aims: (1) Identify morphological characteristics of paretic and non-paretic muscles in chronic stroke and differences with healthy age- matched subjects, (2) Determine whether reductions in muscle force and net joint torque following stroke are due to altered morphology or impaired activation, (3) Identify factors that limit gait speed in persons post-stroke, and (4) Identify differences between self-selected and fastest possible gait speed for healthy persons and those post-stroke. In the proposed series of studies, static MRI will be used to assess physiological cross-sectional area of key lower extremity muscles. Measurements of muscle activity and net joint torque will be taken during a range of isometric and isokinetic dynamometer tasks. Experimental gait data will be collected on healthy and post-stroke individuals and used to generate subject-specific simulations. A variety of analysis techniques will be employed to assess differences between groups, such as muscle excitation patterns, limb configuration, and the potential effect of muscle forces on joint accelerations, and to address clinically relevant hypotheses. PUBLIC HEALTH RELEVANCE: Stroke is a leading cause of long-term adult disability. The relationship between altered muscle force- generating capacity, activation and coordination during walking after stroke is unclear. Through coupled experiments and simulations, we can identify factors that limit gait speed post-stroke and assist rehabilitation professionals in designing treatment interventions that address the specific impairments of an individual subject.