Celik M, Oge A E, Kiliç E, Forta H
Department of Neurology, Sişli Etfal Education and Research Hospital, Istanbul, Turkey.
Electromyogr Clin Neurophysiol. 2004 Mar;44(2):89-94.
The aim of this study was to investigate the changes in cortical excitability in patients with hemifacial spasm (HFS) in order to examine the physiological state of facial nerve nucleus.
Nineteen patients with HFS and 13 control subjects were examined at rest. The procedure was repeated during voluntary contraction in 6 of control subjects. By paired transcranial magnetic stimulation, conditioning and test motor evoked potentials (MEP) were recorded from bilateral orbicularis oris muscles at interstimulus intervals (ISI) of 20, 25, 30, 50, 75 and 100 ms.
In control subjects at rest, ISI's of 20, 25, 30 ms evealed facilitation of the test MEP and inhibition developed at ISI's of 75 and 100 ms. Test MEP facilitation in the contracting controls and on the symptomatic sides of HFS patients was significantly less than the resting controls. Asymptomatic sides of HFS patients behaved similar to the corresponding symptomatic sides and to the contracting controls, although the values were not statistically significant when compared to the resting controls.
The lessening of facilitation found in this study can be interpreted as an abnormal finding that reflects the changes in the excitability of facial motoneuronal system in patients with HFS. However it is difficult to exclude the possibility that this finding can occur due to the normal behavior of cortex during voluntary or involuntary contraction.
本研究旨在调查半面痉挛（HFS）患者皮质兴奋性的变化，以检查面神经核的生理状态。
对19例HFS患者和13名对照者在静息状态下进行检查。在6名对照者进行自主收缩时重复该过程。通过配对经颅磁刺激，在20、25、30、50、75和100毫秒的刺激间隔（ISI）下，从双侧口轮匝肌记录条件和测试运动诱发电位（MEP）。
在静息状态下的对照者中，20、25、30毫秒的ISI显示测试MEP易化，而在75和100毫秒的ISI时出现抑制。收缩状态下的对照者以及HFS患者患侧的测试MEP易化明显低于静息状态下的对照者。HFS患者的健侧表现与相应患侧及收缩状态下的对照者相似，尽管与静息状态下的对照者相比，这些值无统计学意义。
本研究中发现的易化减弱可解释为异常发现，反映了HFS患者面部运动神经元系统兴奋性的变化。然而，难以排除这种发现可能是由于在自主或非自主收缩过程中皮质的正常行为所致的可能性。
