Altered Cortical-Striatal Network in Patients With Hemifacial Spasm

White matter structural changes before and after microvascular decompression for hemifacial spasm

Hemifacial spasm (HFS) is a syndrome characterized by involuntary contractions of the facial muscles innervated by the ipsilateral facial nerve. Currently, microvascular decompression (MVD) is an effective treatment for HFS. Diffusion weighted imaging (DWI) is a non-invasive advanced magnetic resonance technique that allows us to reconstruct white matter (WM) virtually based on water diffusion direction. This enables us to model the human brain as a complex network using graph theory. In our study, we recruited 32 patients with HFS and 32 healthy controls to analyze and compare the topological organization of whole-brain white matter networks between the groups. We also explored the potential relationships between altered topological properties and clinical outcomes. Compared to the HC group, the white matter network was disrupted in both preoperative and postoperative groups of HFS patients, mainly located in the somatomotor network, limbic network, and default network (All P < 0.05, FDR corrected). There was no significant difference between the preoperative and postoperative groups (P > 0.05, FDR corrected). There was a correlation between the altered topological properties and clinical outcomes in the postoperative group of patients (All P < 0.05, FDR corrected). Our findings indicate that in HFS, the white matter structural network was disrupted before and after MVD, and that these alterations in the postoperative group were correlated with the clinical outcomes. White matter alteration here described may subserve as potential biomarkers for HFS and may help us identify patients with HFS who can benefit from MVD and thus can help us make a proper surgical patient selection.

Brain White Matter Structural Alteration in Hemifacial Spasm: A Diffusion Tensor Imaging Study

OBJECTIVE

To analyze the changes in the white matter structure of the whole brain in hemifacial spasm (HFS) patients by using the tract-based spatial statistics (TBSS) method.

MATERIALS AND METHODS

29 HFS patients without anxiety and depression and 29 healthy controls with matching age, sex, and education were selected. All subjects received a 3.0T magnetic resonance (MR) brain diffusion tensor imaging scan. Tract-based spatial statistics method was used to analyze the changes in white matter structure in the whole brain and obtained the cerebral white matter fibrous areas exhibiting significant intergroup differences. The fractional anisotropy (FA), mean diffusivity, axial diffusivity, and radial diffusivity of these areas were abstracted. Analyzed the correlation between these diffusion metrics and clinical variables (disease duration, spasm severity).

RESULTS

Compared with the healthy controls group, the HFS group exhibited significantly lower FA in the forceps minor, bilateral anterior thalamic radiation, and right superior longitudinal fasciculus ( P <0.05, threshold-free cluster enhancement corrected). Cohen grading scale of HFS patients was negatively correlated with FA of forceps minor.

CONCLUSION

Based on TBSS analysis, the injury of white matter fiber tracts in HFS patients was found, including forceps minor, bilateral anterior thalamic radiation, and right superior longitudinal fasciculus. The changes of FA values in forceps minor were negatively correlated with the Cohen grading scale, suggesting that the alteration of white matter fiber in the genu-of-corpus-callosum-cortex circuit plays an important role in the neuro-pathological mechanism of HFS. Combined with previous research, it is also necessary to further explore the change of the superior longitudinal fasciculus in the future.

Different characteristics of striatal resting-state functional conectivity in treatment-resistant and non-treatment-resistant depression

Major depressive disorder is associated with a reward deficit manifested by abnormal striatal function. However, differences between treatment-resistant depression (TRD) and non TRD (nTRD) in striatal whole-brain functional connectivity (FC) have not been elucidated. Thirty-eight patients with TRD, 42 patients with nTRD, and 39 healthy controls (HCs) were recruited for this study. A seed-based FC approach was used to analyze abnormalities in six predefined striatal subregion circuits in the three groups of subjects, and further explore the correlation between abnormal FC and clinical symptoms. Results revealed that compared with the nTRD group, the TRD group showed increased FC of the inferior ventral striatum with the bilateral orbital area of the middle frontal gyrus, right cerebellum posterior lobe, left parahippocampal gyrus, left middle occipital gyrus and left lingual gyrus. Compared with the HC group, the TRD group showed a wider range of altered striatal function than the nTRD group. In the TRD group, the HAMD-17 scores were positively correlated with the FC between the right VRP and the left caudate. This study provides new insights into understanding the specificity of TRD striatal circuits.