Muscle Morphology, Strength and Compensatory Strategies Following Stroke

描述(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的异常，以及肌肉力量产生能力的改变，步态的表现被打乱，出现了不对称的运动学和动力学。这项拟议的工作将调查中风后肌肉形态改变、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施工具，以促进使用Simbios调查人员引入的SimTK框架创建特定于对象的人体运动模拟。我们建议应用该模拟工具包通过实现以下具体目标来了解中风后偏瘫患者的肌肉协调性：(1)确定慢性中风患者瘫痪和非瘫痪肌肉的形态特征以及与年龄匹配的健康受试者的差异；(2)确定中风后肌肉力量和净关节扭矩的减少是由于形态改变还是激活受损，(3)确定限制中风后患者步态速度的因素，以及(4)确定健康人和中风后患者自我选择的和可能的最快步态速度之间的差异。在拟议的一系列研究中，将使用静态MRI来评估关键腿部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长和等速测功器任务中进行。实验步态数据将收集健康和中风后个体的数据，并用于生成特定于受试者的模拟。将使用各种分析技术来评估不同组之间的差异，如肌肉兴奋模式、肢体形状和肌力对关节加速的潜在影响，并解决临床相关假说。公共卫生相关性：中风是导致成人长期残疾的主要原因。中风后行走过程中肌肉力量产生能力的改变、激活和协调性之间的关系尚不清楚。通过耦合的实验和模拟，我们可以确定中风后限制步态速度的因素，并帮助康复专业人员设计针对个别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.