Unilateral facial nerve paralysis induced changes in DMN functional connectivity; a fMRI study

Bell´s palsy (BP) is a common peripheral idiopathic disease affecting the facial nerve (CN VII) causing inability to move facial muscles on the affected side. We investigated BP´s effects on the resting state default mode network (DMN) connectivity. Functional MRI was applied to 20 healthy volunteers and 31 BP patients at different stages with resting state. Patient´s stages were defined based on disease duration and House-Brackmann Score. Dual regression approach was used for ICA based functional connectivity analysis to investigate DMN connectivity changes during different disease stages. All right sided BP patients´ brain maps were flipped so that right brain hemisphere represents lesion side of the brain. It was found in this study that BP induced different brain connectivity changes within DMN varied between different stages.