Failure of Motor Learning in Childhood Dystonia

描述（由申请人提供）：肌张力障碍患儿尽管终生练习，但其运动表现并没有改善。最近的理论结果表明，这可能是由于两种类型的运动学习失败之一：类型1：无法识别相关错误，类型2：无法生成正确行为的例子。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障碍儿童运动控制不良。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和30名对照组儿童将使用2或4块肌肉的表面肌电图活动来控制电脑屏幕上光标的位置。1型衰竭可以通过模糊肌肉活动的视觉信息人为地诱发。2型失败可以通过一项困难的任务引起，其中4块肌肉通过未知的线性混合变换控制4个维度的运动，儿童必须准确地发现一种特定的活动模式。在具体目标1中，我们将证明，当肌肉活动信息被模糊时，控制儿童和肌张力障碍儿童的肌肉共同激活都会增加，正如1型运动学习失败所预测的那样。在具体目标2中，我们将证明，控制儿童和肌张力障碍儿童都无法学习困难的任务，直到在同一任务的简化版本中学习成功的例子。这项研究的成功结果将表明，运动学习的失败是产生儿童肌张力障碍部分运动缺陷的必要和充分条件。它还将展示改善肌张力障碍的策略。特别是，如果提供未观察模式的生物反馈（在这种情况下，二头肌和三头肌的共同收缩），可以改善1型失败。如果在一个简化的任务中向孩子们展示正确的解决方案，这样他们就可以随意地记住和返回正确的解决方案，可以改善第二类失败。这些实验将证明肌张力障碍运动症状的潜在重要因素，并将指出具体的新治疗机会。

DESCRIPTION (provided by applicant): 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 if bio- 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.