Department of Rehabilitation and Movement Science, UMDNJ, Newark, NJ 07101, USA.
Neuromodulation. 2012 Jul;15(4):361-6. doi: 10.1111/j.1525-1403.2012.00467.x. Epub 2012 Jun 1.
Determine if ipsilesional primary motor cortex (M1) in stroke patients processes online visuomotor discordance in gain between finger movement and observed feedback in virtual reality (VR).
Chronic stroke patients flexed (N= 7) or extended (N= 1) their finger with real-time feedback of a virtual hand presented in VR. Virtual finger excursion was scaled by applying a low-gain (G(0.25) ), high-gain (G(1.75) ), or veridical (G(1.00) ) scaling factor to real-time data streaming from a sensor glove. Effects of visuomotor discordance were assessed through analysis of movement kinematics (joint excursion, movement smoothness, and angular velocity) and amplitude of motor evoked potentials (MEPs) elicited with transcranial magnetic stimulation applied to ipsilesional M1. Data were analyzed with a repeated-measures analysis of variance (significance set at 0.05).
G(0.25) discordance (relative to veridical) leads to significantly larger joint excursion, online visuomotor correction evidenced by decreased trajectory smoothness, and significantly facilitated agonist MEPs. This effect could not be explained by potential differences in motor drive (background electromyographic) or by possible differences related to joint angle or angular velocity, as these variables remained invariant across conditions at the time of MEP assessment. M1 was not significantly facilitated in the G(1.75) condition. MEPs recorded in an adjacent muscle that was not involved in the task were unaffected by visual feedback in either discordance condition. These data suggest that the neuromodulatory effects of visuomotor discordance on M1 were relatively selective.
Visuomotor discordance may be used to alter movement performance and augment M1 excitability in patients following stroke. Our data illustrate that visual feedback may be a robust way to selectively modulate M1 activity. These data may have important clinical implications for the development of future VR training protocols.
确定脑卒中患者同侧初级运动皮层（M1）是否处理虚拟现实（VR）中手指运动与观察到的反馈之间增益的在线视动失谐。
慢性脑卒中患者在 VR 中实时反馈虚拟手的情况下弯曲（N=7）或伸展（N=1）手指。虚拟手指的运动幅度通过应用低增益（G(0.25)）、高增益（G(1.75)）或真实增益（G(1.00)）对来自传感器手套的实时数据流进行缩放。通过分析运动运动学（关节运动、运动平滑度和角速度）和经颅磁刺激诱发的运动诱发电位（MEPs）的幅度来评估视动失谐的影响。应用重复测量方差分析（显著性水平设为 0.05）进行数据分析。
与真实增益相比，G(0.25)失谐导致关节运动明显增大，运动平滑度降低，表明在线视动校正，以及明显促进了激动剂 MEPs。这种效应不能用潜在的运动驱动（背景肌电图）差异或与关节角度或角速度相关的可能差异来解释，因为在 MEP 评估时，这些变量在所有条件下保持不变。在 G(1.75)条件下，M1 未明显受到促进。在两种失谐条件下，MEPs 记录于不参与任务的相邻肌肉，不受视觉反馈影响。这些数据表明，视动失谐对 M1 的神经调制效应具有相对选择性。
视动失谐可能用于改变脑卒中患者的运动表现并增强 M1 的兴奋性。我们的数据表明，视觉反馈可能是一种选择性调节 M1 活动的有效方法。这些数据对于未来 VR 训练方案的发展可能具有重要的临床意义。
