基于皮层内抑制调节的皮质反应性与中风康复相关的变化。

Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (INX), École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland (S.H., A.C.-M., T.M., L.F., A.W., M.C., J.B., G.G.E., P.E., E.B., P.M., P.J.K., M.J.W., F.C.H.).

Defitech Chair of Clinical Neuroengineering, INX, EPFL Valais, Clinique Romande de Réadaptation, Sion, Switzerland (S.H., A.C.-M., T.M., L.F., A.W., M.C., J.B., G.G.E., P.E., E.B., P.M., P.J.K., M.J.W., F.C.H.).

Stroke. 2024 Jun;55(6):1629-1640. doi: 10.1161/STROKEAHA.123.045174. Epub 2024 Apr 19.

BACKGROUND

Cortical excitation/inhibition dynamics have been suggested as a key mechanism occurring after stroke. Their supportive or maladaptive role in the course of recovery is still not completely understood. Here, we used transcranial magnetic stimulation (TMS)-electroencephalography coupling to study cortical reactivity and intracortical GABAergic inhibition, as well as their relationship to residual motor function and recovery longitudinally in patients with stroke.

METHODS

Electroencephalography responses evoked by TMS applied to the ipsilesional motor cortex were acquired in patients with stroke with upper limb motor deficit in the acute (1 week), early (3 weeks), and late subacute (3 months) stages. Readouts of cortical reactivity, intracortical inhibition, and complexity of the evoked dynamics were drawn from TMS-evoked potentials induced by single-pulse and paired-pulse TMS (short-interval intracortical inhibition). Residual motor function was quantified through a detailed motor evaluation.

RESULTS

From 76 patients enrolled, 66 were included (68.2±13.2 years old, 18 females), with a Fugl-Meyer score of the upper extremity of 46.8±19. The comparison with TMS-evoked potentials of healthy older revealed that most affected patients exhibited larger and simpler brain reactivity patterns (<0.05). Bayesian ANCOVA statistical evidence for a link between abnormally high motor cortical excitability and impairment level. A decrease in excitability in the following months was significantly correlated with better motor recovery in the whole cohort and the subgroup of recovering patients. Investigation of the intracortical GABAergic inhibitory system revealed the presence of beneficial disinhibition in the acute stage, followed by a normalization of inhibitory activity. This was supported by significant correlations between motor scores and the contrast of local mean field power and readouts of signal dynamics.

CONCLUSIONS

The present results revealed an abnormal motor cortical reactivity in patients with stroke, which was driven by perturbations and longitudinal changes within the intracortical inhibition system. They support the view that disinhibition in the ipsilesional motor cortex during the first-week poststroke is beneficial and promotes neuronal plasticity and recovery.

背景

皮质兴奋/抑制动力学被认为是中风后发生的关键机制。它们在恢复过程中的支持或适应不良作用仍不完全清楚。在这里，我们使用经颅磁刺激（TMS）-脑电图耦合来研究皮质反应性和皮质内 GABA 能抑制作用，以及它们与中风患者上肢运动缺陷的残留运动功能和恢复的关系。

方法

在中风后上肢运动缺陷的急性（1 周）、早期（3 周）和晚期亚急性（3 个月）阶段，采集中风患者对患侧运动皮层 TMS 诱发的脑电图反应。从单脉冲和双脉冲 TMS（短间隔皮质内抑制）诱发的 TMS 诱发电位中得出皮质反应性、皮质内抑制和诱发动力学复杂性的读数。通过详细的运动评估来量化残留运动功能。

结果

从纳入的 76 例患者中，66 例（68.2±13.2 岁，18 名女性）被纳入研究，上肢 Fugl-Meyer 评分为 46.8±19。与健康老年人的 TMS 诱发电位比较发现，大多数受影响的患者表现出更大和更简单的大脑反应模式（<0.05）。贝叶斯方差分析的统计证据表明，异常高的运动皮质兴奋性与损伤程度之间存在关联。在接下来的几个月中，兴奋性的降低与整个队列和恢复患者亚组的更好的运动恢复显著相关。对皮质内 GABA 能抑制系统的研究表明，在急性期存在有益的去抑制作用，随后抑制活性恢复正常。这得到了运动评分与局部平均场功率的对比度和信号动力学读数之间的显著相关性的支持。