Structural changes in the CNS of patients with hemifacial spasm.

Hemifacial spasm (HFS) is a peripheral nerve disorder which impacts the living quality of patients both psychologically and physically. Whether HFS has structural changes under these specific stressors including psychological and physiological conditions in the CNS remains largely unknown. In the current study, voxel-based morphometry (VBM) was used to evaluate changes in gray matter (GM) by using T1-weighted imaging in 25 HFS patients and 25 demographically similar healthy volunteers. The severity of the spasm was assessed using a Cohen evaluation scale. Hamilton anxiety (HAMA) and Hamilton depression (HAMD) rating scales were used to evaluate the affective conditions of subjects. 3D-FIESTA and 3D-TOF sequences were applied to evaluate the neurovascular compression (NVC) rating in each subject. In our results, we found that HFS patients had higher NVC rating scores than those of healthy volunteers, and the spasm severity rating was positively correlated with the NVC rating (r=0.736, p<0.001). HFS patients had higher scores on the HAMA and HAMD compared with healthy volunteers. For the GM comparison, reductions were found in the thalamus, putamen, pallidum, dorsolateral prefrontal cortex, amygdala and parahippocampal gyrus in patients with HFS compared with healthy volunteers. Additionally, the GM volume changes in the amygdala did not exhibit any significant between-group differences with HAMA and HAMD scores as covariates. Our results suggested that HFS probably led to GM volume abnormalities of the CNS. We indicated that the GM volume changes of the amygdala may be highly related to emotional factors.