Altered regional spontaneous neuronal activity in blepharospasm: a resting state fMRI study

The resting state amplitude of low-frequency fluctuations (ALFF) in functional magnetic resonance imaging (fMRI) is believed to reflect spontaneous cerebral neural activity. The pathophysiology of blepharospasm (BSP), which is characterized by motor symptoms and also sensory symptoms, remains unclear. The present study aims to localize possible cerebral functional abnormalities in BSP patients using resting state fMRI, and explore their possible associations with clinical variables. Voxel-based analysis was used to characterize the difference of ALFF between eighteen BSP patients and eighteen matched healthy controls. Separate correlation analyses were conducted to explore the possible association between ALFF values of significantly different areas and clinical measures including onset age, disease duration, symptom severity evaluated by Jankovic rating scale (JRS), and presence of geste antagoniste. The whole-brain analysis indicated that the BSP group had significantly decreased ALFF in the left thalamus while increased ALFF in the left orbitofrontal areas extending from middle frontal gyrus to inferior frontal gyrus. The mean ALFF in the left thalamus was negatively correlated with the subscore of JRS-frequency (r = -0.484, p = 0.042) and JRS total score (r = -0.477, p = 0.045). A borderline positive correlation was detected between the mean ALFF in the left orbitofrontal area and disease duration(r = 0.485, p = 0.049). Our findings suggest sensorimotor integration is abnormal in BSP, and dysfunctional activity of thalamus may be used to measuring symptom severity in BSP patients.