Voxel-Mirrored Homotopic Connectivity of Resting-State Functional Magnetic Resonance Imaging in Blepharospasm

Jing Wei,Chao Qin,Huihui Li,Lu Yang,Shubao Wei,Yiwu Lei,Rongxing Yang,Jingqun Tang,Qiong Yin,Yuhong Qin,Shuguang Luo,Wenbin Guo

doi:10.3389/fpsyg.2018.01620

Abstract

Objective: Several networks in human brain are involved in the development of blepharospasm. However, the underlying mechanisms for this disease are poorly understood. A voxel-mirrored homotopic connectivity (VMHC) method was used to quantify the changes in functional connectivity between two hemispheres of the brain in patients with blepharospasm.Methods: Twenty-four patients with blepharospasm and 24 healthy controls matched by age, sex, and education were recruited. The VMHC method was employed to analyze the fMRI data. The support vector machine (SVM) method was utilized to examine whether these abnormalities could be applied to distinguish the patients from the controls.Results: Compared with healthy controls, patients with blepharospasm showed significantly high VMHC in the inferior temporal gyrus, interior frontal gyrus, posterior cingulate cortex, and postcentral gyrus. No significant correlation was found between abnormal VMHC values and clinical variables. SVM analysis showed a combination of increased VMHC values in two brain areas with high sensitivities and specificities (83.33 and 91.67% in the combined inferior frontal gyrus and posterior cingulate cortex; and 83.33 and 87.50% in the combined inferior temporal gyrus and postcentral gyrus).Conclusion: Enhanced homotopic coordination in the brain regions associated with sensory integration networks and default-mode network may be underlying the pathophysiology of blepharospasm. This phenomenon may serve as potential image markers to distinguish patients with blepharospasm from healthy controls.

Highlights

Blepharospasm (BSP) is a common clinical type of focal dystonia characterized by involuntary blinking and eyelid spasms (Hallett et al, 2008)
No significant correlation was found between abnormal Voxel-mirrored homotopic connectivity (VMHC) values and the severity of symptom, clinical course, and scores of Self-rating Anxiety Scale (SAS) and Self-rating Depression Scale (SDS) in the patients (P > 0.05)
The results showed that the VMHC values in a single brain region could not discriminate patients with BSP from healthy controls with optimal sensitivity, specificity, and accuracy (Table 3), but the patients may be distinguished with high sensitivity, specificity, and accuracy using a combination of two brain regions

Summary

Introduction

Blepharospasm (BSP) is a common clinical type of focal dystonia characterized by involuntary blinking and eyelid spasms (Hallett et al, 2008). BSP is a chronic disease with an incidence rate of 4.2/10 million in general population (Steeves et al, 2012). This disease occurs mostly in adults and manifested with an increased frequency of blinking in the early stage and consistent closed-eyes. Recent techniques, such as neuroimaging, facilitate the exploration of structural and functional abnormalities in patients with BSP. Zhou et al (Zhou et al, 2013) used the amplitude of a low-frequency fluctuation method and found abnormalities in the bilateral somatosensory regions in patients with BSP

Methods

Results

Discussion

Conclusion