Interhemispheric asymmetries of motor cortex excitability in the postacute stroke stage - A paired-pulse transcranial magnetic stimulation study
Interhemispheric asymmetries of motor cortex excitability in the postacute stroke stage - A paired-pulse transcranial magnetic stimulation study
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DOI：
10.1161/01.str.0000092122.96722.72
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发表时间：
2003-11-01
期刊：
影响因子：
8.3
通讯作者：
Rossini, PM
中科院分区：
文献类型：
--
作者：
Cicinelli, P;Pasqualetti, P;Rossini, PM
背景与目的--双脉冲经颅磁刺激运动皮质内抑制(ICI)和易化(ICF)在卒中患者患侧(AH)和健侧(UH)大脑半球的变化反映了与运动皮质可塑性和不同程度功能恢复有关的某些机制。在健康受试者的两个大脑半球中，ICI/ICF斜率的半球间差异具有几乎相同的时间进程，这种对称性在单半球卒中后是否发生改变尚未得到证实。本研究旨在探讨恢复期脑卒中患者急性期和非恢复期ICI/ICF时程的半球间不对称性。方法对10例恢复良好的卒中患者和10例正常对照手部肌肉记录ICI/ICF恢复曲线至阈值条件化阈值上测试磁刺激，并与10例对照组进行比较。卒中患者急性期与急性期的ICI/ICF斜率有显著差异，急性期皮质内抑制作用减弱，而高血压性脑损伤患者皮质内抑制作用减弱。结论缺陷性急性期ICI与有效的UH ICI相关，可作为卒中后皮质可塑性的标志，其机制可能与功能恢复有关。分析ICI/ICF恢复曲线的半球间不对称性可能为单半球卒中患者的预后和随访提供有价值的神经生理学参数。
Background and Purpose - Changes in the intracortical inhibition (ICI) and facilitation (ICF) of motor cortex paired-pulse transcranial magnetic stimulation were reported in the affected (AH) and unaffected (UH) hemispheres of stroke patients and reflect some of the mechanisms related to motor cortex plasticity and different degrees of functional recovery. The interhemispheric differences of the ICI/ICF slopes have been found to have a nearly identical time course in the 2 hemispheres of healthy subjects, and whether such symmetry is modified after monohemispheric stroke has not yet been examined. Our goal was to investigate the interhemispheric asymmetries of the time course of ICI/ICF between the AH and UH of stroke patients in the postacute phase of recovery.Methods - ICI/ICF recovery curves to subthreshold-conditioning suprathreshold-test magnetic stimuli were recorded from the paretic and nonparetic hand muscles of 10 well-recovered stroke patients and compared with those of a population of 10 control subjects.Results - In the healthy subjects, ICI/ICF showed a symmetrical time evolution between the 2 hemispheres. In stroke patients, the ICI/ICF slopes were significantly different between the UH and AH; the intracortical inhibition was reduced in the AH and normal in the UH.Conclusions - The defective AH ICI associated with the effective UH ICI could represent a marker of poststroke cortical plasticity implicated as a mechanism relevant to functional recovery. Analysis of the interhemispheric asymmetries of the ICI/ICF recovery curves might provide a valuable neurophysiological parameter in the prognosis and follow-up of patients with monohemispheric stroke.