Excitability of facial nerve motor nucleus in patients with hemifacial spasm / 中华神经医学杂志

ABSTRACT

Objective:To study whether the excitability of facial nerve motor nucleus is increased in patients with facial spasm to further study the mechanism of facial spasm.Methods:Thirty patients with HFS underwent MVD in our hospital from April 2018 and March 2019 were chosen in our study. The amplitude and threshold voltage of facial nerve motor evoked potential (FNMEP) of the affected side and healthy side were monitored and compared by using monopulse stimulation and multi-pulse stimulation. The changes of FNMEP amplitude in patients before and after sevoflurane inhalation were monitored.Results:Stable facial motor evoked potential could be stimulated by monopulse in 26 patients (89.7%) on the affected side, while only 5 patients (17.2%) on the healthy side, showing statistical difference between the two sides ( P<0.05); there was no significant difference in FNMEP amplitude between the affected side and the healthy side ([207.2±62.1] μV vs. [180.2±55.0] μV, P>0.05); the average threshold voltage of neuromotor evoked potential on the affected side was (140.3±26.8) V, which was significantly lower than that in the healthy side ([177.0±23.2] V, P<0.05). The amplitude of FNMEP on the affected side was (207.2±62.1) μV, (133.0±36.5) μV, and (70.4±40.2) μV, respectively, before sevoflurane inhalation, and at 0.5 fold of minimun alveolar concentration (MAC) and 1.0 fold of MAC concentrations, with significant differences ( P<0.05). Conclusion:In patients with hemifacial spasm, there is increased excitability of facial nerve motor nucleus on the affected side, which to a certain extent supports the central theory of hemifacial spasm pathogenesis.