Effects Of Cerebellum-Cerebrum Dual-Targets Transcranial Magnetic Stimulation On Balance Function And Brain Network In Stroke Patients

Research Background:Stroke is a cerebrovascular disease with high incidence of motor dysfunction.Balance dysfunction is a common motor dysfunction.Balance recovery is the basic function of motor function recovery and quality of life improvement.Transcranial magnetic stimulation(TMS)is an effective treatment tool to improve balance function in stroke patients,where stimulation target on cerebellum is an effective way to improve balance function.In addition to the cerebellum(CB),the primary motor cortex(M1)and supplementary motor area(SMA)also play key roles in balance control.Due to the structural and functional connections between cerebellum and cerebrum,we suppose a combination of stimulation targets that can improve balance function,whose therapeutic effects is superior than single cerebellum target.Functional near-infrared spectroscopy(f NIRS)has an advantage of anti-motion interference which is suitable for assessing brain activity during balance tasks and the effect of TMS on cerebral cortex.Objective:The objective of this study was to explore the immediate effect of cerebellum-cerebrum dual-targets TMS on balance function in stroke patients.We used f NIRS to explore the modulation effect of cerebellum-cerebrum dual-targets TMS on cortical network in stroke patients.The cortical activation characteristics of patients performing balance tasks before and after intervention was observed.Methods:31 patients with first-time subcortical stroke,who met the inclusion criteria were recruited in rehabilitation medicine department of Huashan Hospital Affiliated to Fudan University.They were randomly divided into single cerebellum target group,CB-M1 target group and CB-SMA target group.In the single cerebellum group,intermittent theta-burst stimulation(i TBS)intervention was applied to the cerebellar hemisphere opposite the affected cerebral cortex,with a total of 600 stimulation pulses.The CB-M1 group applied one i TBS stimulation to cerebellum and M1 respectively,with a total of 1200 pulses.The CB-SMA group applied i TBS stimulus to the cerebellum and SMA,each with a total of 1200 pulses.Balance function(Center of pressure,COP)and brain activity evaluation were conducted before and immediately after the intervention(f NIRS measurement including resting state and brain activation during standing balance with eyes-open and closed condition).Results:A total of 31 patients completed the trial with no adverse events.(1)Balance function assessment system: COP parameters in the eye-open condition has no difference among groups before and after TMS intervention(P > 0.05).In the eyes-closed condition,significant differences among groups were observed.Post-hoc comparison indicates that the reduction degree in the left and right ranges of CB-SMA group was better than CB-M1 group(P = 0.009)and CB-single group(P = 0.023);the reduction degree in the left-right acceleration of CB-SMA group was better than that of CB-single group(P = 0.009);the improvement on COP long axis in CB-SMA group was better than that in CB-M1 group(P = 0.003)and CB-single group(P = 0.006);the improvement of swing area in the CB-SMA group was better than that of CB-M1group(P = 0.011).(2)The f NIRS showed that the cerebral cortex of the CB-SMA group showed inhibition after intervention where the most significant connectivity reduction was between Ch.7 and Ch.11(T =-7.746,P < 0.001).Only one connection between Ch.33 and Ch.13 indicated a decreasing of connectivity in the motor network in CB-M1 group.A few functional connectivity was reduced in the CB-single group.Among the three resting-state results,only the CB-SMA group passed the FDR correction.(3)Region of interest(ROI)analysis: a total of 24 channels showed decreased connectivity after CB-SMA intervention(P < 0.016).Functional connectivity between ROI and dorsolateral prefrontal cortex in the affected hemisphere showed significant difference after i TBS intervention(P < 0.001).(4)The brain activation of three groups were inconsistent after i TBS intervention while there was no significant difference.Conclusion:The results showed that single TMS application to the CB-SMA could immediately improve the balance function of patients with eyes closed.f NIRS results suggested that stimulation on the CB-SMA reduced the functional connectivity in the cerebral cortex,thereby reorganized the functional brain network.This study provides a new TMS program for the clinical treatment of balance function in stroke patients.