Failure of Motor Learning in Childhood Dystonia

患有肌张力障碍的儿童尽管一生都在练习，但他们的运动表现并没有提高。近期 理论结果表明，这可能是由于运动学习失败的两种类型之一： 类型1：无法识别相关错误， 类型2：无法生成正确行为的示例。 我们提出了一组实验来证明运动学习的失败可能导致运动能力差。 肌张力障碍儿童的对照研究。为了验证这一假设，30名患有原发性或继发性肌张力障碍的儿童 30名对照儿童将使用2或4块肌肉的表面肌电活动来控制姿势 计算机屏幕上的光标。第一类故障可以通过模糊视觉信息来人为地诱导 关于肌肉的活动。用4块肌肉控制4块肌肉的高难度任务可以诱发II型衰竭 通过未知的线性混合变换运动的维度，孩子们必须发现 只有一种特定的活动模式。在具体目标1中，我们将演示控制儿童和 肌张力障碍儿童表现出肌肉协同激活增加，当肌肉活动信息 模糊，正如运动学习的1型失败所预测的那样。在具体目标2中，我们将证明两者 控制儿童和肌张力障碍儿童无法学习困难的任务，直到一个成功的例子是 在同一任务的简化版本中学习。这项研究的成功结果将表明， 运动学习是造成儿童肌张力障碍部分运动缺陷的必要条件和充分条件。会的 还展示了改善肌张力障碍的策略。具体地说，类型1的故障可以在以下情况下得到改善： 提供了未观察到的模式的反馈(在这种情况下，二头肌和三头肌的共同收缩)。类型2 如果在简化的任务中向孩子们展示正确的解决方案，那么失败就会得到改善，这样他们就可以 然后记住并随意返回正确的解决方案。这些实验将证明一种潜在的 是肌张力障碍患者运动症状的重要因素，它们将指明具体的新治疗方法 机遇。

Children with dystonia do not improve their movement performance despite a lifetime of practice. Recent theoretical results suggest that this may be due to one of two types of failure of motor learning: Type 1: inability to recognize relevant errors, Type 2: inability to generate examples of correct behavior. We propose a set of experiments to demonstrate that failure of motor learning may contribute to poor motor control in children with dystonia. To test this hypothesis, 30 children with primary or secondary dystonia and 30 control children will use surface electromyographic activity of either 2 or 4 muscles to control the position of cursors on a computer screen. Type 1 failure can be induced artificially by obscuring visual information about muscle activity. Type 2 failure can be induced using a difficult task in which 4 muscles control 4 dimensions of movement through an unknown linear mixing transformation, and the children must discover exactly one specific pattern of activity. In specific aim 1, we will demonstrate that both control children and children with dystonia show increased co-activation of muscles when information about muscle activity is obscured, as predicted by type 1 failure of motor learning. In specific aim 2, we will demonstrate that both control children and children with dystonia are unable to learn a difficult task until a successful example is learned in a simplified version of the same task. A successful result of this study will show that failure of motor learning is necessary and sufficient to produce part of the motor deficits in childhood dystonia. It will also show strategies for improvement of dystonia. In particular, type 1 failure can be improved ifbio- feedback of an unobserved mode (in this case, co-contraction of biceps and triceps) is provided. Type 2 failure can be improved if the correct solution is presented to children in a simplified task, so that they can then remember and return to the correct solution at will. These experiments will demonstrate a potentially important contributor to motor symptoms in dystonia, and they will indicate specific new treatment opportunities.