Predicting Ipsilesional Motor Deficits in Stroke with Dynamic Dominance Model

描述(由申请人提供)：单侧感觉-运动中风可导致与病变同侧的手臂和腿部严重的运动障碍(自发性)，此外还会在身体的另一侧造成更严重的缺陷(对侧)。虽然在临床上认识到自身的缺陷已经有几十年了，但治疗的注意力集中在对侧缺陷的更严重的性质上，这是可以理解的。然而，最近证明，自身缺陷大大限制了功能性任务的有效执行，包括日常生活活动。这样的限制并不难理解，因为在中到重度偏瘫患者的单手和双手任务中，偏瘫患者的偏瘫手臂往往被用作主要操纵器。这些协调缺陷被认为是由于受损的大脑半球对控制身体同侧手臂的贡献减少所致，这一观点得到了我们初步研究的支持。基于运动偏侧化的动态优势模型，我们希望能够解释和预测由右脑或左脑损伤引起的单手和双手协调的差异性缺陷。拟议的研究利用了两个实验室的专业知识，这两个实验室在研究中风患者的运动偏侧化(Sainburg)和自发性运动表现(Haaland)方面投入了大量精力。[我们希望我们的结果在康复方面有切实的应用，包括开发干预措施来改善慢性中风患者的单侧和双侧功能。]我们建议的实验使用定制设计的虚拟现实系统来检查目标到达动作，该系统允许实时显示和记录双侧手臂的动作。前两个目的直接检验我们的偏侧化模型对自身运动控制和学习的预测。具体地说，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，我们还将研究这种协调缺陷对功能表现的潜在影响。我们的第二个目标是检查单侧中风是否会产生随病变侧不同而不同的运动学习缺陷。我们的第三和第四个目标解决了可能导致自身缺陷的具体控制过程：第一，我们询问左脑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，我们考察了右脑损伤导致的位置误差是由阻抗控制机制缺陷造成的，还是由空间位置指定的缺陷造成的。在我们的最后一项研究中，我们将测试我们的模型对虚拟物体运输和操纵任务中双边协调的预测。这对中重度偏瘫患者尤其重要，他们经常依靠双手手臂使用来进行日常生活活动。此外，最近的研究表明，双边锻炼可以作为这类患者的一种有效的治疗方式(Harris-Love等人，2005年)。好了！ 与公共健康相关：美国心脏协会报告称，美国每年约有78万人经历新发或复发的中风，其中很大一部分涉及大脑半球的不对称损害。因为大脑两个半球并不是彼此的功能镜像，任何一个半球的损伤都会在中风患者的两个手臂上产生独特的缺陷，包括非瘫痪的手臂。本文提出的研究应该能更全面地了解中风患者非偏瘫手臂的运动缺陷，以及这些缺陷对单手和双手协调的影响。这对中重度偏瘫患者尤其重要，他们倾向于依靠非偏瘫的手臂进行日常生活活动。我们期望我们的发现能为临床康复和康复研究带来切实的应用。

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.