Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin , Milwaukee, Wisconsin.
Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genova , Genoa , Italy.
J Neurophysiol. 2019 Jul 1;122(1):22-38. doi: 10.1152/jn.00337.2018. Epub 2019 Apr 17.
We examined vibrotactile stimulation as a form of supplemental limb state feedback to enhance planning and ongoing control of goal-directed movements. Subjects wore a two-dimensional vibrotactile display on their nondominant arm while performing horizontal planar reaching with the dominant arm. The vibrotactile display provided feedback of hand position such that small hand displacements were more easily discriminable using vibrotactile feedback than with intrinsic proprioceptive feedback. When subjects relied solely on proprioception to capture visuospatial targets, performance was degraded by proprioceptive drift and an expansion of task space. By contrast, reach accuracy was enhanced immediately when subjects were provided vibrotactile feedback and further improved over 2 days of training. Improvements reflected resolution of proprioceptive drift, which occurred only when vibrotactile feedback was active, demonstrating that benefits of vibrotactile feedback are due, in part to its integration into the ongoing control of movement. A partial resolution of task space expansion persisted even when vibrotactile feedback was inactive, demonstrating that training with vibrotactile feedback also induced changes in movement planning. However, the benefits of vibrotactile feedback come at a cognitive cost. All subjects adopted a stereotyped strategy wherein they attempted to capture targets by moving first along one axis of the vibrotactile display and then the other. For most subjects, this inefficient approach did not resolve over two bouts of training performed on separate days, suggesting that additional training is needed to integrate vibrotactile feedback into the planning and online control of goal-directed reaching in a way that promotes smooth and efficient movement. A two-dimensional vibrotactile display provided state (not error) feedback to enhance control of a moving limb. Subjects learned to use state feedback to perform blind reaches with accuracy and precision exceeding that attained using intrinsic proprioception alone. Feedback utilization incurred substantial cognitive cost: subjects moved first along one axis of the vibrotactile display, then the other. This stereotyped control strategy must be overcome if vibrotactile limb state feedback is to promote naturalistic limb movements.
我们研究了振动触觉刺激作为补充肢体状态反馈的一种形式，以增强对目标导向运动的规划和持续控制。受试者在非优势手臂上佩戴二维振动触觉显示器，同时用优势手臂进行水平平面伸手。振动触觉显示器提供手位置的反馈，使得较小的手位移使用振动触觉反馈比使用固有本体感觉反馈更容易区分。当受试者仅依靠本体感受来捕捉视觉空间目标时，由于本体感受漂移和任务空间的扩展，表现会下降。相比之下，当受试者提供振动触觉反馈时，立即提高了伸手的准确性，并在两天的训练中进一步提高。改进反映了本体感受漂移的分辨率，只有在振动触觉反馈处于活动状态时才会发生漂移，这表明振动触觉反馈的好处部分归因于其整合到运动的持续控制中。即使在振动触觉反馈不活跃时，任务空间扩展的部分分辨率仍然存在，这表明使用振动触觉反馈进行训练也会引起运动规划的变化。然而，振动触觉反馈的好处需要付出认知代价。所有受试者都采用了一种刻板的策略，即他们试图通过先沿振动触觉显示器的一个轴移动，然后再沿另一个轴移动来捕获目标。对于大多数受试者来说，这种低效的方法在两天的单独训练中并没有得到解决，这表明需要额外的训练才能将振动触觉反馈整合到目标导向伸手的规划和在线控制中，以促进运动的平稳和高效。二维振动触觉显示器提供状态（而非误差）反馈，以增强对运动肢体的控制。受试者学会使用状态反馈以高精度和高精度执行盲目伸手，超过单独使用固有本体感觉所达到的精度。反馈利用产生了大量的认知成本：受试者首先沿振动触觉显示器的一个轴移动，然后沿另一个轴移动。如果要促进自然的肢体运动，那么必须克服这种刻板的控制策略。
