Brain Plasticity Laboratory, Department of Physical Therapy, University of Illinois at Chicago, Chicago, Illinois, USA.
Graduate Program in Rehabilitation Sciences, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, Illinois, USA.
Eur J Neurosci. 2023 Aug;58(3):2853-2867. doi: 10.1111/ejn.16069. Epub 2023 Jun 24.
Cross-education, a phenomenon where unilateral strength (or skill) training enhances strength (or skill) in the contralateral untrained limb, has been well studied in able-bodied individuals. Cross-education effect accompanies bilateral changes of corticomotor activity in the motor cortex (M1). Recent reports demonstrated greater cross-education effect in stroke survivors compared to healthy individuals, however, corticomotor responses to cross-education in stroke remains unclear. This study aimed to determine the effects of non-paretic leg movements on corticomotor excitability (CME) and reaction time of the paretic leg in severely impaired stroke survivors. Seventeen post stroke individuals with severe leg motor impairment (Fugl-Meyer lower extremity score less than 21 and absence of motor evoked potential in the paretic leg) performed three 20-min motor trainings using their non-paretic ankle: skill (targeted dynamic movements), strength (isometric resistance) and sham (sub-threshold electrical nerve stimulation). During training, verbal instructions were given to the participants to limit their movement to the non-paretic leg and this was confirmed with visual observation of the paretic leg. Transcranial magnetic stimulation measured CME of the contralateral pathways from the non-lesioned M1 to the non-paretic tibialis anterior (TA) muscle, ipsilateral pathways to the paretic TA and transcallosal inhibition (TCI) from the non-lesioned to lesioned M1. Paretic ankle reaction time was measured using a reaction time paradigm. All outcomes were measured before, immediately post, 30-min post and 60-min post priming. CME of the non-paretic TA increased after skill (.08 ± .10 mV) and strength (.06 ± .05 mV) training (p < .01). Ipsilateral CME of the paretic TA (.02 ± .01 mV) and TCI (.01 ± .01 s, ipsilateral silent period; more inhibition to the lesioned M1) increased after skill (p < .05) but not strength training. Reaction time of the paretic ankle improved after skill and strength training (-.11 ± .2 and -.13 ± .20 s, respectively; p < .05) and was sustained at 60 min. No changes were observed during the sham condition. Our findings may inform future studies for using non-paretic leg movements as a priming modality, especially for those who are contraindicated to other priming paradigms (e.g., brain stimulation) or unable to perform paretic leg movements. Conclusion: Non-paretic leg movements can be used as a priming modality, especially for those who are contraindicated to other priming paradigms (e.g., brain stimulation) or unable to perform paretic leg movements.
交叉教育是一种现象，即单侧力量（或技能）训练增强对未训练侧肢体的力量（或技能），在健全个体中已有很好的研究。交叉教育效应伴随着运动皮层（M1）中运动皮质兴奋性的双侧变化。最近的报告表明，中风幸存者的交叉教育效应大于健康个体，但中风后运动皮质兴奋性对交叉教育的反应仍不清楚。本研究旨在确定非瘫痪腿运动对严重受损中风幸存者瘫痪腿运动皮质兴奋性（CME）和反应时间的影响。17 名中风后下肢运动功能严重受损的患者（下肢 Fugl-Meyer 评分低于 21 分，瘫痪侧无运动诱发电位）使用非瘫痪侧踝关节进行三种 20 分钟的运动训练：技能（靶向动态运动）、力量（等长阻力）和假（阈下电神经刺激）。在训练过程中，向参与者口头指示限制其运动至非瘫痪侧，并通过观察瘫痪侧来确认。经颅磁刺激测量来自非病变 M1 到非瘫痪胫骨前肌（TA）的对侧通路、病变 TA 的同侧通路和来自非病变 M1 到病变 M1 的交叉皮质抑制（TCI）的 CME。使用反应时范式测量瘫痪侧踝关节的反应时间。所有结果均在预刺激、刺激后即刻、刺激后 30 分钟和刺激后 60 分钟测量。技能（.08±.10 mV）和力量（.06±.05 mV）训练后非瘫痪 TA 的 CME 增加（p<.01）。技能训练后瘫痪侧 TA 的同侧 CME（.02±.01 mV）和 TCI（.01±.01 s，同侧静息期；对病变 M1 的抑制增加）增加（p<.05），但力量训练后无变化。技能和力量训练后瘫痪侧踝关节反应时间改善（分别为-.11±.2 和-.13±.20 s；p<.05），并在 60 分钟时保持不变。假条件下无变化。我们的发现可能为未来使用非瘫痪腿运动作为启动模式提供信息，特别是对于那些不适合其他启动模式（例如脑刺激）或无法进行瘫痪侧腿部运动的患者。结论：非瘫痪侧腿部运动可作为启动模式，特别是对于那些不适合其他启动模式（例如脑刺激）或无法进行瘫痪侧腿部运动的患者。
