Increased functional connectivity coupling with supplementary motor area in blepharospasm at rest

To explore the abnormalities of brain function in blepharospasm (BSP) and to illustrate its neural mechanisms by assuming supplementary motor area (SMA) as the entry point.

Twenty-five patients with BSP and 23 controls underwent resting-state functional MRI, seed-based functional connectivity (FC), correlation analysis, receiver operating characteristic curve (ROC) analysis, and support vector machine (SVM) were applied to process the data.

Patients showed that the left medial prefrontal cortex (MPFC), left lingual gyrus, right cerebellar crus I, and right lingual gyrus/cerebellar crus I had enhanced FC with the left SMA, whereas the right inferior temporal gyrus (ITG) had enhanced FC with the right SMA relative to controls. The FC between the left MPFC and left SMA was positively correlated with symptomatic severity. The ROC analysis verified that the abnormal FCs demonstrated in this study can separate patients and controls at high sensitivity and specificity. SVM analysis exhibited that combined FCs of the left SMA were optimal for distinguishing patients and control group at the accuracy of 89.58%, with sensitivity of 92.00% and specificity of 86.96%.

Several brain networks partake in the neurobiology of BSP. SMA plays a vital role in several brain networks and might be the key pathogenic factor in BSP.

Providing novel evidence for the engagement of the MPFC in the motor symptoms of BSP, enhancing credibility of the thesis that SMA regulates the neurobiology of BSP, and providing ideas of screening susceptible population of BSP using neuroimaging.