الملخص
Objective:To further elucidate the pathogenesis of hemifacial spasm by analyzing blinking reflex characteristics.Methods:A total of 63 patients with hemifacial spasm (hemifacial spasm group) who underwent neuroelectrophysiological evaluation in Department of Neurological Electrophysiology, Guizhou Provincial People's Hospital from January 2021 to December 2022 were included as study subjects. Additionally, 58 patients with primary trigeminal neuralgia (trigeminal neuralgia group), 8 patients with post-facial paralysis associated exercise (post-facial paralysis associated exercise group), and 20 healthy volunteers (normal group) were selected as controls. Differences in facial nerve motor conduction velocity, complex muscle action potential latency, and blinking reflex characteristics including R1 latency, R1 amplitude, R2 initiation latency, R2 amplitude, R2 terminal latency, R2' initiation latency recorded on the affected side, R2' amplitude recorded on the affected side, and R2' terminal latency recorded on the affected side were collected and compared. Severity of hemifacial spasm was graded from grade 1 to grade 4 according to Samsung Medical Center scoring system; based on microvascular decompression findings regarding responsible blood vessels contacted with the facial nerve, patients were divided into one responsible blood vessel group and two or more responsible blood vessels group; trends or differences in incidences of increased/prolonged blink reflex indexes among all groups were analyzed.Results:No significant difference in facial nerve motor conduction velocity or complex muscle action potential latency was noted among the 4 groups ( P>0.05); the hemifacial spasm group had significantly higher R1 amplitude than the trigeminal neuralgia group and post-facial paralysis associated exercise group; additionally, the hemifacial spasm group had significantly higher R2 amplitude, R2' amplitude recorded on the affected side, R2 terminal latency, and R2' terminal latency recorded on the affected side compared with the other 3 groups ( P<0.05). Among patients with varying degrees of hemifacial spasm, increased incidences of increased R1 amplitude and prolonged R2 terminal latency were noted with increased spasm degrees, enjoying significant differences ( P<0.05). No significant differences in incidences of increased R1 amplitude, increased R2 amplitude, prolonged R2 terminal latency, increased R2' amplitude recorded on the affected side or prolonged R2' terminal latency recorded on the affected side were noted between one responsible blood vessel group and two or more responsible blood vessels group ( P>0.05). Conclusion:Increased R1 amplitude and prolonged R2 latency in patients with hemifacial spasm further substantiate the pathogenesis of hyperexcitability within facial nerve nucleus.
الملخص
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.