Abstract：
BACKGROUND: It has been proposed that tics and premonitory urges in primary tic disorders (PTD), like Tourette syndrome, are a manifestation of sensorimotor noise. However, patients with tics show no obvious movement imprecision in everyday life. One reason could be that patients have strategies to compensate for noise that disrupts performance (ie, noise that is task-relevant).
OBJECTIVE: Our goal was to unmask effects of elevated sensorimotor noise on the variability of voluntary movements in patients with PTD.
METHODS: We tested 30 adult patients with PTD (23 male) and 30 matched controls in a reaching task designed to unmask latent noise. Subjects reached to targets whose shape allowed for variability either in movement direction or extent. This enabled us to decompose variability into task-relevant versus less task-relevant components, where the latter should be less affected by compensatory strategies than the former. In alternating blocks, the task-relevant target dimension switched, allowing us to explore the temporal dynamics with which participants adjusted movement variability to changes in task demands.
RESULTS: Both groups accurately reached to targets, and adjusted movement precision based on target shape. However, when task-relevant dimensions of the target changed, patients initially produced movements that were more variable than controls, before regaining precision after several reaches. This effect persisted across repeated changes in the task-relevant dimension across the experiment, and therefore did not reflect an effect of novelty, or differences in learning.
CONCLUSIONS: Our results suggest that patients with PTD generate noisier voluntary movements compared with controls, but rapidly compensate according to current task demands. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
OBJECTIVE: Our goal was to unmask effects of elevated sensorimotor noise on the variability of voluntary movements in patients with PTD.
METHODS: We tested 30 adult patients with PTD (23 male) and 30 matched controls in a reaching task designed to unmask latent noise. Subjects reached to targets whose shape allowed for variability either in movement direction or extent. This enabled us to decompose variability into task-relevant versus less task-relevant components, where the latter should be less affected by compensatory strategies than the former. In alternating blocks, the task-relevant target dimension switched, allowing us to explore the temporal dynamics with which participants adjusted movement variability to changes in task demands.
RESULTS: Both groups accurately reached to targets, and adjusted movement precision based on target shape. However, when task-relevant dimensions of the target changed, patients initially produced movements that were more variable than controls, before regaining precision after several reaches. This effect persisted across repeated changes in the task-relevant dimension across the experiment, and therefore did not reflect an effect of novelty, or differences in learning.
CONCLUSIONS: Our results suggest that patients with PTD generate noisier voluntary movements compared with controls, but rapidly compensate according to current task demands. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
摘要：
背景：有人提出，在原发性抽动障碍（PTD）中抽动和先兆催促，比如Tourette综合征,是感觉运动噪音的表现。然而,抽动患者在日常生活中没有明显的运动不精确性。一个原因可能是患者有补偿干扰表现的噪音的策略(即，与任务相关的噪声)。
目的：我们的目的是消除PTD患者感觉运动噪声升高对自主运动变异性的影响。
方法：我们测试了30名患有PTD的成年患者（23名男性）和30名匹配的对照，其目的是消除潜在噪声。受试者到达其形状允许运动方向或范围变化的目标。这使我们能够将可变性分解为与任务相关的组件，而不是与任务相关的组件，后者应受到补偿策略的影响小于前者。在交替块中，切换了与任务相关的目标维度，允许我们探索参与者根据任务需求的变化调整运动变异性的时间动态。
结果：两组均准确达到目标，并根据目标形状调整运动精度。然而,当目标的任务相关维度发生变化时，患者最初产生的运动比对照组变化更大，在几次达到后恢复精度之前。这种效果在整个实验中任务相关维度的重复变化中持续存在，因此没有反映出新颖性的影响，或学习上的差异。
结论：我们的研究结果表明，与对照组相比，PTD患者产生更大的自主运动，但根据当前任务要求迅速补偿。©2024作者由WileyPeriodicalsLLC代表国际帕金森症和运动障碍协会出版的运动障碍。
目的：我们的目的是消除PTD患者感觉运动噪声升高对自主运动变异性的影响。
方法：我们测试了30名患有PTD的成年患者（23名男性）和30名匹配的对照，其目的是消除潜在噪声。受试者到达其形状允许运动方向或范围变化的目标。这使我们能够将可变性分解为与任务相关的组件，而不是与任务相关的组件，后者应受到补偿策略的影响小于前者。在交替块中，切换了与任务相关的目标维度，允许我们探索参与者根据任务需求的变化调整运动变异性的时间动态。
结果：两组均准确达到目标，并根据目标形状调整运动精度。然而,当目标的任务相关维度发生变化时，患者最初产生的运动比对照组变化更大，在几次达到后恢复精度之前。这种效果在整个实验中任务相关维度的重复变化中持续存在，因此没有反映出新颖性的影响，或学习上的差异。
结论：我们的研究结果表明，与对照组相比，PTD患者产生更大的自主运动，但根据当前任务要求迅速补偿。©2024作者由WileyPeriodicalsLLC代表国际帕金森症和运动障碍协会出版的运动障碍。
