Comparative study of brain perfusion network changes in blepharospasm and blepharospasm-oromandibular dystonia

Blepharospasm (BSP) has a high spreading risk, and the most common condition is becoming blepharospasm-oromandibular dystonia (BOM). We aimed to identify the shared and specific changes in the brain cerebral blood flow (CBF) covariance network between BSP and BOM.

This single-center study enrolled 21 BSP patients, 21 BOM patients, and 20 healthy controls (HC). Clinical information and MRI imaging including arterial spin labeling, three-dimensional T1-weighted and conventional sequences were obtained. CBF data were preprocessed, and group-level CBF covariance networks were constructed. Intergroup differences of network connections and properties were compared using a permutation test, and for all network metrics, the statistical significance was defined as p< 0.01 (uncorrected, 5000 times).

In both patient groups, hypoperfusion is mainly located in the bilateral frontal lobe and cingulate gyrus. The global properties were standard, and spatial covariance analysis revealed whole-brain reconfiguration. CBF connections in BSP patients were partially increased, whereas they were mostly decreased in BOM patients. Two groups shared lost hubs in the vermis 8, left putamen, right superior temporal gyrus, right cerebellum 4-5, and left thalamus. Compared with BSP, the BOM group showed more widespread decreased connections linking these lost hubs to the rest of the brain, especially for the left putamen, left thalamus and right superior temporal gyrus hub.

Loss function in the vermis 8, left putamen, right superior temporal gyrus, right cerebellum 4-5, and left thalamus are important features for the pathophysiology of both patient groups. Among them, decreased connections in the left putamen, left thalamus, and right superior temporal gyrus mainly unveiled the specific pathophysiological differences between groups.