# Abnormal inter-hemispheric functional cooperation in blepharospasm

## TL;DR

This study finds increased brain connectivity between hemispheres in people with blepharospasm, a condition causing involuntary eye muscle contractions.

## Contribution

The study reveals novel hyperconnectivity in motor-related brain regions in blepharospasm patients using resting-state fMRI.

## Key findings

- Blepharospasm patients showed increased inter-hemispheric connectivity in the left putamen and precentral gyrus.
- Aberrant connectivity did not correlate with disease duration or severity scores.
- The findings suggest hyperconnectivity may be a compensatory mechanism in blepharospasm.

## Abstract

Blepharospasm, characterized by involuntary contractions of the orbicularis oculi muscles, significantly impairs the quality of life. Its pathophysiology remains unclear. Inter-hemispheric cooperation is a prominent feature of the human brain. This study utilizes resting-state functional magnetic resonance imaging (rs-fMRI) to explore inter-hemispheric functional cooperation in blepharospasm patients by examining connectivity between functionally homotopic voxels (CFH), aiming to identify neural disruptions associated with the disorder.

We recruited 30 patients with blepharospasm and 30 age-, sex-, and education-matched healthy controls. All participants underwent rs-fMRI scanning. CFH maps were generated for each participant to quantify inter-hemispheric connectivity at the voxel level. Group differences were assessed, and partial correlation analyses were performed in the patient group to examine the relationship between aberrant CFH values and clinical variables.

Compared to healthy controls, patients with blepharospasm showed significantly increased CFH in the left putamen and left precentral gyrus. However, these aberrant CFH values did not significantly correlate with clinical variables, including disease duration or total Jankovic Rating Scale (JRS) scores and its subscales.

This study identifies increased inter-hemispheric functional connectivity (FC) within key motor-related brain regions in blepharospasm. The observed hyperconnectivity in the putamen and precentral gyrus may reflect a compensatory neural mechanism to counteract motor dysfunction. These findings provide novel insights into the pathophysiology of blepharospasm and suggest that modulating inter-hemispheric communication may be a potential therapeutic target.