Resting state fMRI observations of baseline brain functional activities and connectivities in primary blepharospasm

Primary blepharospasm (BPS) is a focal dystonia characterized by involuntary eyelid spasms and blinking. The pathophysiology of BPS remains unclear. Several functional and structural neuroimaging studies have demonstrated abnormalities of sensorimotor structures such as the sensorimotor cortex, the basal ganglia, the thalamus and the cerebellum in BPS patients. However, some of the results of these studies were inconsistent. In addition, the relationship between the motor and sensory structures in patients with BPS still needs to be investigated. Therefore, the purpose of this study was to investigate the abnormal alterations in both the intra-regional brain activities and inter-regional functional connectivities (FC) in patients with BPS using resting-state functional MRI(rs-fMRI) and to explore possible correlations between these rs-fMRI indices and clinical variables. The rs-fMRI images of the two groups of subjects (26 BPS patients and 26 healthy controls) were acquired using a 3.0T MRI scanner. The regional rs-fMRI indices, i.e., the fractional amplitude of the low-frequency fluctuation (fALFF) and the regional homogeneity (ReHo), were computed for all subjects. Then, two-sample t-tests were conducted to assess the significant differences between the two groups of subjects. To investigate the alterations in brain networks, cerebral regions with significant differences were used as regions of interest in the whole brain FC analysis. Compared to the control group, the BPS patients revealed significantly increased fALFF and ReHo values in the right caudate head. Significantly strengthened FC values were observed between the right caudate head and the left striatum and the right supplementary motor area in the BPS group. The fALFF and ReHo values in the right caudate head and the FC values between the right caudate head and the left striatum were positively correlated with the Jankovic Rating Scale sum score. In conclusion, this study indicated that BPS patients have both abnormal intra-regional spontaneous brain activities and inter-regional functional connectivities.