Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, School of Medicine, University of Minnesota, 426 Church St. SE, Minneapolis, MN 55455, USA; Department of Neurology, School of Medicine, University of Minnesota, 717 Delaware St. SE, Minneapolis, MN 55414, USA.
Divisions of Physical Therapy and Rehabilitation Science, Department of Rehabilitation Medicine, School of Medicine, University of Minnesota, 426 Church St. SE, Minneapolis, MN 55455, USA; Non-invasive Neuromodulation Laboratory, MnDRIVE Initiative, University of Minnesota, 247, 717 Delaware St. SE, Minneapolis, MN 55414, USA.
Clin Neurophysiol. 2020 Jun;131(6):1272-1279. doi: 10.1016/j.clinph.2020.03.019. Epub 2020 Apr 2.
Dystonia is associated with reduced intracortical inhibition as measured by the cortical silent period (cSP); however, this may be due to abnormal cSP threshold or input-output properties. This study evaluated cSP recruitment properties in people with cervical dystonia (CD).
Bilateral electromyographic recordings were collected in the upper trapezius muscle in response to transcranial magnetic stimulation of the left and right primary motor cortex in a group with CD (n = 19) and controls (n = 21). cSP threshold, cSP input-output properties at stimulation intensities from 1 to 1.4x the cSP threshold, ipsilateral silent period duration (iSP) and timing and magnitude of the contralateral and ipsilateral motor evoked potential (MEP) were assessed.
The cSP threshold, input-output properties, and contralateral MEP magnitude were not significantly different between groups (all p > 0.07). Hemispheric symmetry was present in the control group while the CD group had reduced iSP (p < 0.01) and a trend for reduced ipsilateral MEP response (p = 0.053) in the left hemisphere.
Recruitment properties of intracortical inhibition are similar between control and CD groups. Transcallosal inhibition is asymmetric between hemispheres in people with CD.
Evidence of normal intracortical inhibition recruitment properties challenge the commonly held view that cortical inhibition is reduced in dystonia.
肌紧张与皮质静息期（cSP）所测皮质内抑制减少有关；然而，这可能是由于 cSP 阈值或输入-输出特性异常。本研究评估了颈性肌张力障碍（CD）患者的 cSP 募集特性。
在 19 名 CD 患者和 21 名对照组中，分别记录双侧斜方肌上部的肌电图，以响应左、右侧初级运动皮层的经颅磁刺激。评估 cSP 阈值、刺激强度为 cSP 阈值的 1 至 1.4 倍时的 cSP 输入-输出特性、同侧静息期持续时间（iSP）以及对侧和同侧运动诱发电位（MEP）的时间和幅度。
两组间 cSP 阈值、输入-输出特性和对侧 MEP 幅度均无显著差异（均 p>0.07）。对照组存在半球对称性，而 CD 组左侧 iSP 降低（p<0.01），对侧 MEP 反应降低（p=0.053）。
皮质内抑制的募集特性在对照组和 CD 组之间相似。CD 患者的皮质间抑制呈半球间不对称。
皮质抑制减少在肌张力障碍中普遍存在的观点受到皮质内抑制募集特性正常的证据的挑战。
