Multi-modal MRI Study Of Low-frequency Repetitive Transcranial Magnetic Stimulation In The Treatment Of Post-stroke Spasticity

Objective: Through multi-modal MRI technology,to observe the changes of excitability in the brain area related to spasticity and its correlation with the degree of spasticity relief before and after the treatment of low frequency repetitive transcranial magnetic stimulation(rTMS).To explore the central mechanism of low-frequency rTMS in the treatment of post-stroke spasticity(PSS),which provide important theoretical basis for clinical treatment.Methods: A total of 36 patients with spastic hemiplegia(MAS ≥ 1)were selected and divided into two groups: conventional treatment group(12 cases)and rTMS group(24 cases).Both groups received conventional exercise therapy,rTMS group increased low-frequency rTMS stimulation on this basis.The intervention lasted for 8 weeks.Before and after treatment,the patients were assessed with Fugl-Meyer scale(FMA-UE),modified Barthel index(MBI),modified Ashworth scale(MAS)and MRI.At the same time,20 patients with non spastic hemiplegia(MAS = 0)were matched as the control group of MRI of spastic patients.Results: 1.After treatment,the FMA-UE and MBI scores in both group were significantly increased(P < 0.05),and the MAS scores of the rTMS group were significantly reduced(P < 0.05),but there was no significant difference in the MAS scores of the conventional treatment group(P > 0.05).2.Compared with the conventional treatment group,the FMA-UE and MBI scores of the rTMS group were significantly higher(P < 0.05),and the MAS scores were significantly lower(P < 0.05)after treatment.3.The severity of spasticity(MAS)was negatively correlated with motor function(FMA-UE)and activity of daily living(MBI)in rTMS group(P < 0.01).4.VLSM analysis showed that insular lobe,thalamus,anterior corona radiata and superior longitudinal fasciculus were significantly correlated with spasticity of upper extremity(P < 0.05,FDR corrected).5.Before treatment,the precentral gyrus,postcentral gyrus and putamen of the contralesional hemisphere were significantly activated in rTMS group compared with non-spastic group(P < 0.001,uncorrected).6.After treatment,the activation of the contralesional hemisphere(M1,S1,insula)and bilateral hemispheres(putamen,thalamus)decreased significantly(P < 0.001,uncorrected)in rTMS group.7.The results of ROI analysis showed that the activated volume and intensity of M1 and S1 in the contralesional hemisphere were significantly higher than those in the ipsilesional hemisphere(P < 0.05)before treatment.After treatment,the activated volume and intensity of ROIs in the contralesional hemisphere decreased significantly(P < 0.05),the number of activation in the contralesional hemisphere(M1,S1)shifted to the ipsilesional hemisphere,there was no significant difference between the left and right sides of all ROIs(P > 0.05).8.The improvement of spasticity(MAS score)was positively correlated with the decrease of activated intensity in M1 and S1 regions of the contralesional hemisphere.Conclusions: 1.Low-frequency rTMS can effectively relieve the upper extremity spasticity and promote the recovery of motor function and activities of daily living(ADL).2.Low frequency rTMS can not only significantly reduce the excitability of the sensorimotor area in the contralesional hemisphere,but also significantly reduce the excitability of thalamus,putamen and insular lobe.The findings indicate that the mechanism of rTMS in the treatment of spasticity is not only through the way of restoring the balance between hemispheres,but also indirectly affects the excitability of other brain regions such as subcortical basal ganglia,which provides theoretical support for the promotion of clinical application of rTMS.