Department of Neurology, NYU Grossman School of Medicine, New York, United States.
Department of Basic and Clinical Sciences, University of Nicosia Medical School, Nicosia, Cyprus; Center for Neuroscience and Integrative Brain Research (CENIBRE), University of Nicosia Medical School, Nicosia, Cyprus.
J Neurol Sci. 2023 Jul 15;450:120688. doi: 10.1016/j.jns.2023.120688. Epub 2023 May 13.
To determine if the distribution of transcallosal inhibition (TI) acting on proximal and distal upper extremity muscles is altered in chronic stroke.
We examined thirteen healthy controls and sixteen mildly to moderately impaired chronic stroke patients. We used transcranial magnetic stimulation (TMS) to probe TI from the contralesional onto ipsilesional hemisphere (assigned in controls). We recorded the ipsilateral silent period in the paretic biceps (BIC) and first dorsal interosseous (FDI). We measured TI strength, distribution gradient (TI difference between muscles), and motor impairment (Fugl-Meyer Assessment).
Both groups had stronger TI acting on their FDIs than BICs (p < 0.001). However, stroke patients also had stronger TI acting on their BICs than controls (p = 0.034), resulting in a flatter distribution of inhibition (p = 0.028). In patients, stronger FDI inhibition correlated with less hand impairment (p = 0.031); BIC inhibition was not correlated to impairment.
TI is more evenly distributed to the paretic FDI and BIC in chronic stroke. The relative increase in proximal inhibition does not relate to better function, as it does distally.
The results expand our knowledge about segment-specific neurophysiology and its relevance to impairment after stroke.
确定近端和远端上肢肌肉的经皮质抑制（TI）分布在慢性中风中是否发生改变。
我们检查了 13 名健康对照者和 16 名轻度至中度慢性中风患者。我们使用经颅磁刺激（TMS）从对侧半球探测对侧半球上的 TI（在对照组中指定）。我们记录了瘫痪侧二头肌（BIC）和第一背骨间肌（FDI）的同侧静息期。我们测量了 TI 强度、分布梯度（肌肉之间的 TI 差异）和运动障碍（Fugl-Meyer 评估）。
两组对 FDI 的 TI 均强于 BIC（p<0.001）。然而，中风患者对 BIC 的 TI 也强于对照组（p=0.034），导致抑制的分布更平坦（p=0.028）。在患者中，更强的 FDI 抑制与手功能障碍程度较低相关（p=0.031）；BIC 抑制与损伤无关。
TI 在慢性中风中更均匀地分布于瘫痪的 FDI 和 BIC。与远端相比，近端抑制的相对增加与功能改善无关。
结果扩展了我们对特定于节段的神经生理学及其与中风后损伤的相关性的认识。
