Department of Physical Therapy, College of Applied Health Sciences, University of Illinois, Chicago, Illinois.
J Neurophysiol. 2020 Jul 1;124(1):20-31. doi: 10.1152/jn.00671.2019. Epub 2020 May 13.
This study determined the effect of mixed (slip- and trip-like stance perturbation) training on reactive responses in people with chronic stroke (PwCS) and examined modulation of their reactive responses on higher intensity perturbations posttraining (scaling). Twelve PwCS were exposed to consecutive blocks of treadmill-based slip-like and trip-like perturbations and mixed-stance perturbations. A higher intensity trial was provided postblock and postmixed training. Postural stability [center-of-mass position (CoMP) and velocity (CoMV)], compensatory step length, step count, and trunk angle were examined. PwCS demonstrated an anterior positioning of the CoM, increased step length, and reduced compensatory step count with slip-like block training ( < 0.05). Trip-like block training resulted in reductions in step count, step length, and trunk angle ( < 0.05); however, CoMP remained unchanged ( > 0.05). With mixed training, there was a decrease rather than an increase in step length for slip-like perturbations but a continued decrease in step length and trunk angle was seen on trip-like perturbations ( < 0.05); however, CoMP and step count remained unchanged for both. For both perturbations, the higher intensity trials demonstrated no change from the last block trial. Postmixed block, the higher intensity trial demonstrated an increase only in step count on trip-like perturbation. Between postblock and postmixed higher intensity trials, an increase in step count and decrease in step length was noted only for slip-like perturbations. Block training with slip- and trip-like stance perturbations can enhance reactive responses among PwCS. Although mixed perturbation training continued to improve trip-induced adaptation, prior slip-induced adaptive changes were not maintained and further slip-adaptation was not seen. PwCS demonstrated partial scaling of reactive responses postblock and postmixed training. Block perturbation training led to development of favorable reactive responses to counteract treadmill-based, slip-like and trip-like stance perturbations among people with chronic stroke. During mixed block, previously acquired adaptive changes in reactive responses from slip-block training were not maintained, probably due to interference offered by trip block. Instead, on trip-like perturbations, trip block-induced adaptation was maintained and continued to show further improvement. Our findings might provide future direction for designing effective mixed perturbation training paradigms to counteract both opposing perturbation types.
本研究旨在确定混合（滑动和绊倒样姿势扰动）训练对慢性脑卒中患者（PwCS）反应能力的影响，并探讨训练后（缩放）对更高强度扰动的反应能力的调节。12 名 PwCS 接受了基于跑步机的滑动样和绊倒样扰动以及混合姿势扰动的连续块训练。在块和混合训练后提供更高强度的试验。检查姿势稳定性[质心位置（CoMP）和速度（CoMV）]、代偿步长、步数和躯干角度。PwCS 在滑动块训练时表现出 CoM 的前定位、增加的步长和减少的代偿步数（<0.05）。在绊倒块训练时，步长、步数和躯干角度减少（<0.05）；然而，CoMP 保持不变（>0.05）。在混合训练中，滑动样扰动的步长没有增加，反而减少，但绊倒样扰动的步长和躯干角度继续减少（<0.05）；然而，CoMP 和步数在两种情况下都保持不变。对于两种扰动，高强度试验与最后一个块试验相比没有变化。在混合块之后，只有在绊倒样扰动的高强度试验中，步长才增加。在块后和混合后高强度试验之间，只有滑动样扰动的步数增加，步长减少。滑动和绊倒样姿势扰动的块训练可以增强 PwCS 的反应能力。尽管混合扰动训练继续改善绊倒引起的适应，但以前滑动引起的适应性变化没有得到维持，也没有进一步的滑动适应。PwCS 在块和混合后高强度试验后表现出部分反应能力的缩放。块扰动训练导致慢性脑卒中患者对跑步机上的滑动样和绊倒样姿势扰动产生有利的反应能力。在混合块期间，由于绊倒块提供的干扰，以前从滑动块训练中获得的反应能力适应性变化没有得到维持，而是在绊倒样扰动上，保持了绊倒块引起的适应性，并继续进一步改善。我们的发现可能为设计有效的混合扰动训练方案提供未来方向，以对抗两种相反的扰动类型。
