Comparing Brain Functional Activities in Patients With Blepharospasm and Dry Eye Disease Measured With Resting-State fMRI.

Changqiang Feng,Wenbin Guo,Shuguang Luo,Jing Wei,Lulu Pang,Meilan Liang,Wenyan Jiang,Yiwu Lei,Jingqun Tang,Yousheng Xiao,Wenmei Li,Yang Liu,Yulin Lu

doi:10.3389/fneur.2021.607476

Abstract

Background: Blepharospasm (BSP) and dry eye disease (DED) are clinically common diseases characterized by an increased blinking rate. A sustained eyelid muscle activity may alter the cortical sensorimotor concordance and lead to secondary functional changes. This study aimed to explore the central mechanism of BSP by assessing brain functional differences between the two groups and comparing them with healthy controls.Methods: In this study, 25 patients with BSP, 22 patients with DED, and 23 healthy controls underwent resting-state functional magnetic resonance imaging (fMRI) scan. The amplitude of low-frequency fluctuations (ALFF) was applied to analyze the imaging data.Results: Analysis of covariance (ANCOVA) revealed widespread differences in ALFF across the three groups. In comparison with healthy controls, patients with BSP showed abnormal ALFF in the sensorimotor integration related-brain regions, including the bilateral supplementary motor area (SMA), left cerebellar Crus I, left fusiform gyrus, bilateral superior medial prefrontal cortex (MPFC), and right superior frontal gyrus (SFG). In comparison with patients with DED, patients with BSP exhibited a significantly increased ALFF in the left cerebellar Crus I and left SMA. ALFF in the left fusiform gyrus/cerebellar Crus I was positively correlated with symptomatic severity of BSP.Conclusions: Our results reveal that the distinctive changes in the brain function in patients with BSP are different from those in patients with DED and healthy controls. The results further emphasize the primary role of sensorimotor integration in the pathophysiology of BSP.

Highlights

Characterized by excessive involuntary spasms of the orbicularis oculi, blepharospasm (BSP) is recognized as a common form of adult-onset focal dystonia [1, 2]
A total of 70 participants were included in the study: 25 patients with BSP, patients with dry eye disease (DED), and healthy controls
Abnormal ALFF values were located in the sensorimotor integration related brain regions in patients with BSP, including the bilateral SMA, left cerebellar Crus I, left fusiform gyrus, bilateral superior MPFC, and right SFG compared with healthy controls

Summary

Introduction

Characterized by excessive involuntary spasms of the orbicularis oculi, blepharospasm (BSP) is recognized as a common form of adult-onset focal dystonia [1, 2] As disease progresses, it may result in difficulty in opening the eyes or even functional blindness, which causes functional disability in work and daily life and decreases quality of life [3,4,5]. These unpleasant sensations in DED often initiated secondary increased blink rate This might be a result of increased reflex non-spasmodic closure of the eyelids to the sensory symptoms other than the involuntary orbicularis oculi spasms in BSP. Differences in neural activity between the two diseases remain unclear, and sustained muscular activity might alter the cortical sensory-motor concordance directly or indirectly, leading to secondary structural or functional changes that are almost indistinguishable from the underlying pathophysiological characteristics of BSP. This study aimed to explore the central mechanism of BSP by assessing brain functional differences between the two groups and comparing them with healthy controls

Objectives

Methods

Results

Conclusion