Department of Physical Medicine & Rehabilitation, NYU School of Medicine, New York, NY, United States; Department of Neurology, NYU School of Medicine, New York, NY, United States; Department of Biomedical Engineering, NYU School of Engineering, New York, NY, United States.
Department of Physical Medicine & Rehabilitation, NYU School of Medicine, New York, NY, United States.
Prog Brain Res. 2019;249:361-374. doi: 10.1016/bs.pbr.2019.04.013. Epub 2019 Jun 6.
Within the domain of motor performance, eye-hand coordination centers on close relationships between visuo-perceptual, ocular and appendicular motor systems. This coordination is critically dependent on a cycle of feedforward predictions and feedback-based corrective mechanisms. While intrinsic feedback harnesses naturally available movement-dependent sensory channels to modify movement errors, extrinsic feedback may be provided synthetically by a third party for further supplementation. Extrinsic feedback has been robustly explored in hand-focused, motor control studies, such as through computer-based visual displays, highlighting the spatial errors of reaches. Similar attempts have never been tested for spatial errors related to eye movements, despite the potential to alter ocular motor performance. Stroke creates motor planning deficits, resulting in the inability to generate predictions of motor performance. In this study involving visually guided pointing, we use an interactive computer display to provide extrinsic feedback of hand endpoint errors in an initial baseline experiment (pre-) and then feedback of both eye and hand errors in a second experiment (post-) to chronic stroke participants following each reach trial. We tested the hypothesis that extrinsic feedback of eye and hand would improve predictions and therefore feedforward control. We noted this improvement through gains in the spatial and temporal aspects of eye-hand coordination or an improvement in the decoupling noted as incoordination post-stroke in previous studies, returning performance toward healthy, control behavior. More specifically, results show that stroke participants, following the interventional feedback for eye and hand, improved both their accuracy and timing. This was evident through a temporal re-synchronization between eyes and hands, improving correlations between movement timing, as well as reducing the overall time interval (delay) between effectors. These experiments provide a strong indication that an extrinsic feedback intervention at appropriate therapeutic doses may improve eye-hand coordination during stroke rehabilitation.
在运动表现领域，手眼协调主要集中在视知觉、眼部和附属运动系统之间的紧密关系上。这种协调严重依赖于前馈预测和基于反馈的校正机制的循环。虽然内在反馈利用自然可用的运动相关感觉通道来修正运动误差，但外在反馈可以由第三方提供，以进一步补充。外在反馈在手为中心的运动控制研究中得到了广泛的探索，例如通过基于计算机的视觉显示器，突出显示到达的空间误差。尽管有可能改变眼球运动表现，但类似的尝试从未在与眼球运动相关的空间误差方面进行过测试。中风会导致运动计划缺陷，导致无法预测运动表现。在这项涉及视觉引导指向的研究中，我们在初始基线实验（预）中使用交互式计算机显示器提供手部末端误差的外在反馈，然后在第二次实验（后）中提供眼部和手部误差的外在反馈，用于慢性中风参与者在每次到达试验后。我们假设外在反馈的眼睛和手会改善预测，从而改善前馈控制。我们通过眼手协调的空间和时间方面的增益或改善在之前的研究中被认为是中风后不协调的解耦来注意到这一改善，使性能恢复到健康、对照行为。更具体地说，结果表明，中风参与者在接受眼和手的干预性反馈后，提高了准确性和计时。这可以通过眼睛和手之间的时间重新同步来证明，这改善了运动时间之间的相关性，并减少了效应器之间的整体时间间隔（延迟）。这些实验强烈表明，在适当的治疗剂量下进行外在反馈干预可能会改善中风康复期间的手眼协调。
