Background

Stroke rehabilitation may be improved with a better understanding of the contribution of ipsilateral motor pathways to the paretic limb and alterations in transcallosal inhibition. Few studies have evaluated these factors during dynamic, bilateral lower limb movements, and it is unclear whether they relate to functional outcomes.

Objective

Determine if lower limb ipsilateral excitability and transcallosal inhibition after stroke depend on target limb, task, or number of limbs involved, and whether these factors are related to clinical measures.

Methods

In 29 individuals with stroke, ipsilateral and contralateral responses to transcranial magnetic stimulation were measured in the paretic and nonparetic tibialis anterior during dynamic (unilateral or bilateral ankle dorsiflexion/plantarflexion) and isometric (unilateral dorsiflexion) conditions. Relative ipsilateral excitability and transcallosal inhibition were assessed. Fugl-Meyer, ankle movement accuracy, and walking characteristics were assessed.

Results

Relative ipsilateral excitability was greater during dynamic than isometric conditions in the paretic limb (P ≤ .02) and greater in the paretic than the nonparetic limb during dynamic conditions (P ≤ .004). Transcallosal inhibition was greater in the ipsilesional than contralesional hemisphere (P = .002) and during dynamic than isometric conditions (P = .03). Greater ipsilesional transcallosal inhibition was correlated with better ankle movement accuracy (R² = 0.18, P = .04). Greater contralateral excitability to the nonparetic limb was correlated with improved walking symmetry (R² = 0.19, P = .03).

Conclusions

Ipsilateral pathways have increased excitability to the paretic limb, particularly during dynamic tasks. Transcallosal inhibition is greater in the ipsilesional than contralesional hemisphere and during dynamic than isometric tasks. Ipsilateral pathways and transcallosal inhibition may influence walking asymmetry and ankle movement accuracy.

中文翻译：

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中风后下肢运动过程中的同侧运动通路和经胼胝体抑制

背景

通过更好地了解同侧运动通路对麻痹肢体的贡献和经胼胝体抑制的改变，可以改善中风康复。很少有研究在动态、双侧下肢运动过程中评估这些因素，尚不清楚它们是否与功能结果有关。

客观的

确定中风后下肢同侧兴奋性和经胼胝体抑制是否取决于目标肢体、任务或涉及的肢体数量，以及这些因素是否与临床措施有关。

方法

在 29 名卒中患者中，在动态（单侧或双侧踝关节背屈/跖屈）和等长（单侧背屈）条件下，在瘫痪和非瘫痪胫骨前部测量了同侧和对侧对经颅磁刺激的反应。评估了相对同侧兴奋性和经胼胝体抑制。评估了 Fugl-Meyer、踝关节运动准确性和步行特征。

结果

相对同侧兴奋性在动态条件下大于等长条件下的瘫痪肢体 ( P ≤ .02) 和大于非瘫痪肢体在动态条件下 ( P ≤ .004) 。同侧半球的经胼胝体抑制大于对侧半球 ( P = .002) 并且在动态期间比等长条件下 ( P = .03)更大。更大的同侧经胼胝体抑制与更好的踝关节运动准确性相关（R ² = 0.18，P = .04）。非瘫痪肢体更大的对侧兴奋性与改善的步行对称性相关（R ² = 0.19，P = .03）。

结论

同侧通路增加了麻痹肢体的兴奋性，尤其是在动态任务中。经胼胝体抑制在同侧比对侧半球和动态过程中比等长任务更大。同侧通路和经胼胝体抑制可能会影响步行不对称和踝关节运动的准确性。