Predicting Ipsilesional Motor Deficits in Stroke with Dynamic Dominance Model

描述（由申请人提供）：单侧感觉运动中风可引起与病变同侧身体的手臂和腿部明显的运动缺陷（同侧），此外在身体的另一侧产生更严重的运动缺陷（对侧）。虽然同侧缺陷在临床上已经被认识了几十年，但治疗的注意力可以理解地集中在对侧缺陷更严重的性质上。然而，最近的研究表明，同脑缺陷极大地限制了功能性任务的有效执行，包括日常生活活动。这些限制并不难理解，因为对于中度至重度偏瘫患者，在单手和双手任务中，同侧手臂往往被用作主要的操纵器。这些协调缺陷被认为是由于受损半球对身体同侧手臂控制的贡献减少，我们的初步研究支持了这一观点。基于运动侧化的动态优势模型，我们希望解释和预测由左右半球损伤引起的单手和双手协调的差异缺陷。拟议的研究利用了两个实验室的专业知识，他们在研究脑卒中患者的运动侧化（Sainburg）和同侧运动表现（Haaland）方面投入了大量精力。[我们期望我们的研究结果对康复有切实的应用，包括开发干预措施来改善慢性中风患者的同侧和双侧功能。]我们提出的实验使用定制设计的虚拟现实系统来检查目标伸手运动，该系统允许实时显示和记录双侧手臂运动。前两个目的直接检验我们的侧化模型对同视运动控制和学习的预测。具体来说，我们将研究节段间协调缺陷是否由左半球损伤引起，而位置缺陷是否由右半球损伤引起。此外，我们将研究这种协调缺陷对功能表现的潜在影响。我们的第二个目的是研究单侧中风是否会产生运动学习缺陷，这种缺陷随损伤部位的不同而不同。我们的第三和第四个目标是解决可能构成同侧缺陷的特定控制过程：首先，我们询问左半球相关的协调和适应缺陷是否与预测任务动态的错误有关。其次，我们研究了右半球损伤导致的位置误差是由阻抗控制机制的缺陷引起的，还是由空间位置规范的缺陷引起的。在我们最后的研究中，我们将测试我们的模型在虚拟物体运输和操作任务中的双边协调预测。这对于中度至重度偏瘫患者尤其重要，他们经常依靠双手使用手臂进行日常生活活动。此外，最近的研究表明，双侧运动可以作为这类患者的有效治疗方式（Harris-Love et al, 2005）。！

DESCRIPTION (provided by applicant): Unilateral sensory-motor stroke can cause significant motor deficits in the arm and leg on the same side of the body as the lesion (ipsilesional), in addition to producing more severe deficits on the opposite side of the body (contralesional). While ipsilesional deficits have been recognized in the clinic for decades, therapeutic attention has understandably focused on the more severe nature of contralesional deficits. However, ipsilesional deficits have recently been shown to substantially limit efficient performance of functional tasks, including activities of daily living. Such limitations are not difficult to understand given that the ipsilesional arm tends to be used as the primary manipulator during both unimanual and bimanual tasks for patients with moderate to severe hemiparesis. These coordination deficits are thought to result from diminished contributions from the damaged hemisphere to control of the arm on the same side of the body, an idea supported by our preliminary studies. Based on the dynamic dominance model of motor lateralization, we hope to explain and predict the differential deficits in unimanual and bimanual coordination that result from either right or left hemisphere damage. The proposed studies exploit the expertise of two laboratories that have invested substantial effort in studying motor lateralization (Sainburg), and ipsilesional motor performance in stroke patients (Haaland). [We expect our results to have tangible applications to rehabilitation, including the development of interventions to improve ipsilesional and bilateral function in chronic stroke patients.] Our proposed experiments examine targeted reaching movements, using a custom designed virtual-reality system that allows real-time display and recording of bilateral arm movements. The first two aims directly examine predictions from our model of lateralization for ipsilesional motor control and learning. Specifically, we will examine whether intersegmental coordination deficits result from left hemisphere damage, while positional deficits result from right hemisphere damage. In addition, we will examine the potential effect of such coordination deficits on functional performance. Our second aim examines whether unilateral stroke produces motor learning deficits that vary with the side of the lesion. Our third and fourth aims address the specific control processes that might underlie ipsilesional deficits: First, we ask whether left hemisphere related deficits in coordination and adaptation are related to errors in predicting task dynamics. Second, we examine whether position errors that result from right hemisphere damage are accounted for by deficient impedance control mechanisms, or rather by deficits in specification of spatial locations. In our final study, we will test our model's predictions for bilateral coordination during virtual object transportation and manipulation tasks. This is particular important for patients with moderate to severe hemiparesis, who often rely on bimanual arm use to carry out activities of daily living. In addition, recent research has indicated that bilateral exercise can serve as an effective therapeutic modality for such patients (Harris-Love et al, 2005). ! PUBLIC HEALTH RELEVANCE: The American Heart Association reports that each year, about 780,000 people in the United States experience a new or recurrent stroke, a large proportion of which involves asymmetrical damage to the cerebral hemispheres. Because the cerebral hemispheres are not functional mirror images of one another, lesion to either hemisphere can produce unique deficits in both arms of stroke patients, including the non-paretic arm. The studies proposed here should lead to a more complete understanding of motor deficits in the non-paretic arm of stroke patients, and the effects of these deficits on both unimanual and bimanual coordination. This is particularly important for patients with moderate to severe hemiparesis, who tend to rely on the non-paretic arm to carry out activities of daily living. We expect that our findings should produce tangible applications to clinical rehabilitation, and to rehabilitation research.