A Resting-state Functional MRI Study Of Patients With Hemifacial Spasm

Background: Hemifacial spasm(HFS)is a neuromuscular movement disorder generally characterized by unilateral,involuntary,and intermittent contractions of the muscles innervated by the ipsilateral facial nerve,which impacts the living quality of patients both physiologically and physically.However,the dysfunction of the central nervous system in patients with hemifacial spasm has not been well clarified.To our knowledge,it is the first study that uses resting-state functional magnetic resonance imaging to compare alterations of brain function in left-sided hemifacial spasm patients and right-sided hemifacial spasm patients.Methods: In the present study,we evaluated the changes of the brain activity in 34 patients with hemifacial spasm and in 34 controls by combining regional homogeneity(ReHo)and amplitudes of low-frequency fluctuation(ALFF)methods based on resting-state fMRI and to determine the relationship of these functional changes with clinical features.Meanwhile,we also compare 15 left-sided HFS and 15 right-sided HFS with their controls respectively in terms of their spontaneous brain activity.Results:(1)Compared to the controls,left-sided HFS patients has significantly decreased ALFF values in right cerebellum anterior lobe/lobule VI and left middle occipital gyrus.However,there is no significant differences between HFS patients and the controls,and between right-sided HFS patients and the controls.Meanwhile,no significant differences was found between left-sided HFS patients and right-sided HFS patients.Furthermore,the ALFF value in these altered brain regions showes no correlation with patients' duration and the spasm severity.(2)Compared to the controls,HFS patients has significantly decreased ReHo values in right cerebellum posterior lobe/lobule VIIIb and right cerebellum posterior lobe/lobule VI,increased ReHo values in left inferior temporal gyrus.Left-sided HFS patients has significantly decreased ReHo values in left fusiform gyrus and cerebellum posterior lobe/lobule VI,right cerebellum posterior lobe/lobule VI,left middle occipital gyrus and left postcentral gyrus,increased ReHo values in left parahippocampa gyrus and left inferior frontal gyrus.Compared to the right-sided HFS patients,left-sided HFS patients has more ReHo results in left inferior frontal gyrus,right middle frontal gyrus and right inferior parietal lobule.Furthermore,the ReHo value in these altered brain regions showes no correlation with patients' duration and the spasm severity.Conclusion: This study reveals that HFS is associated with abnormal spontaneous brain activity in brain regions most involved in visual process,motor control,sensorimotor integration,emotion regulation and cognitive function.Furthermore,the dysfunction of the brain regions in patients with left-sided HFS was inconsistent with that in patients with right-sided HFS.Perhaps because of the small sample size after splitting HFS patients,most of the results cannot afford FWE correction.Since HFS is one of the peripheral neuropathies,it probably has secondary impact on spontaneous brain activity.Meanwhile,our results reveal the difference in the influence of brain function between left-side HFS and right-sided HFS.Therefore,further study is needed to demonstrate and provide insights into the central mechanism of HFS.