OBJECTIVE Deficits in ankle motor control has been identified as a significant contributor to impaired walking after stroke. Corticomotor excitability has been related to impaired upper limb motor control and poor recovery in stroke, however contributions to lower limb function are still unclear. This study used transcranial magnetic stimulation (TMS) to determine the influence of corticomotor characteristics on lower limb motor control in chronic stroke survivors. METHODS This retrospective study assessed 28 individuals with post stroke hemiparesis. Motor evoked potentials (MEP) measured from the paretic and non-paretic tibialis anterior (TA) muscles were used to calculate corticomotor excitability symmetry (CMEsym) and relative ipsilateral corticomotor excitability (ICE). Participants were assigned to MEP+ and MEP- groups depending on the presence (+) or absence (-) of MEPs. Ankle motor control was quantified by the ability of participants to track a sinusoidal target using dorsiflexion-plantarflexion movements of the paretic ankle and tracking error was calculated using root mean square error (RMSE). RESULTS Multiple linear regression model for all participants revealed only CMEsym and FMLE (p < 0.01) to significantly predict RMSE. In the MEP+ group, CMEsym significantly predicted RMSE (p = 0.03) while FMLE (p = 0.02) was a significant predictor for the MEP-. CONCLUSION Our results indicate that CMEsym between the ipsilesional and contralesional hemispheres does not necessarily translate to better paretic ankle motor control in chronic stroke. Presence or absence of a MEP in the TA muscle did not affect the ankle tracking performance, however, it was noted that different strategies maybe used by those with and without a MEP.

中文翻译：

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具有和不具有运动诱发电位的卒中后个体踝关节运动控制的不同皮质运动机制。

目的 踝关节运动控制的缺陷已被确定为中风后行走障碍的重要因素。皮质运动兴奋性与上肢运动控制受损和中风恢复不良有关，但对下肢功能的影响尚不清楚。本研究使用经颅磁刺激 (TMS) 来确定皮质运动特性对慢性中风幸存者下肢运动控制的影响。方法 这项回顾性研究评估了 28 名中风后偏瘫患者。从麻痹和非麻痹胫骨前 (TA) 肌肉测量的运动诱发电位 (MEP) 用于计算皮质运动兴奋性对称性 (CMEsym) 和相对同侧皮质运动兴奋性 (ICE)。根据 MEP 的存在 (+) 或不存在 (-)，参与者被分配到 MEP+ 和 MEP- 组。踝关节运动控制通过参与者使用瘫痪踝关节的背屈-跖屈运动跟踪正弦目标的能力来量化，跟踪误差使用均方根误差 (RMSE) 计算。结果 所有参与者的多元线性回归模型仅显示 CMEsym 和 FMLE (p < 0.01) 可显着预测 RMSE。在 MEP+ 组中，CMEsym 显着预测了 RMSE (p = 0.03)，而 FMLE (p = 0.02) 是 MEP- 的显着预测因子。结论 我们的结果表明，同侧和对侧半球之间的 CMEsym 并不一定转化为更好的慢性卒中中的瘫痪踝关节运动控制。