The Effects Of TMS With Different Modes On Lower Limb Function In Stroke Patients And Its Mechanism

Objective:To compare the therapeutic effects and change of brain activation and functional network connections of 10 Hz repetitive transcranial magnetic stimulation(r TMS)and intermittent theta burst stimulation(i TBS)on lower limb dysfunction in stroke patients by using f NIRS,isokinetic muscle strength test system,clinical motor function scales and nerve electrophysiological indexes.Methods:45 stroke patients with lower limb dysfunction were randomly divided into control group,repetitive transcranial magnetic stimulation group(r TMS group)and intermittent theta burst stimulation group(i TBS group).The control group received conventional rehabilitation training(CRT)combined with sham stimulation,while the r TMS group received CRT combined with 10 Hz r TMS,and the i TBS group received CRT combined with i TBS.Before and 3 weeks after treatment,the lower extremity motor function and balance function were separately evaluated by the peak torque of the affected knee flexor and extensor muscles(PT),the ratio of flexor and extensor muscles peak toeque(F/E),the Fugl-Meyer assessment of lower extremity scale(FMA-LE),Berg balance scale(BBS)and the modified Ashworth rating scale(MAS).The nerve electrophysiological indexes were separately evaluated by motor evoked potential(MEP)cortical latency of tibialis anterior muscle in the affected lower limbs and central motor conduction time(CMCT).By recording the concentration of Hb O in regions of interest(ROI)under different tasks to calculating the beta value and the functional connection strength between ROIs,it was evaluated the differences in brain activation and functional network connections.The regions of interest were supplementary motor cortex(SMA),sensorimotor cortex(SMC)and prefrontal cortex(PFC)of the affected hemisphere and unaffected hemisphere.Results:1.The sex,age,course of disease,stroke type,Brunnstrom stage and other general data of the three groups were statistically analyzed.The results showed that the difference was not statistically significant.2.Before treatment,there was no significant difference in PT of the affected knee flexor and extensor muscles,F/E,FMA-LE score,MAS score,BBS score,MEP cortical latency and CMCT value of tibialis anterior muscle among the three groups(P>0.05).After 3 weeks of treatment,the PT of the affected knee flexor and extensor muscles,F/E,FMA-LE score,MAS score,BBS score,MEP cortical latency and CMCT were significantly different from those in the same group before treatment(P<0.05).Compared with the control group,PT,F/E,FMA-LE score and BBS score were significantly increased in r TMS group and i TBS group(P<0.05),while the cortical latency and central motor conduction time of MEP were significantly decreased in r TMS group and i TBS group(P<0.05).There was no significant difference in MAS score among the three groups after 3 weeks of treatment(P>0.05).3.Before treatment,in the step task test of the three groups,the β value of SMC on the unaffected hemisphere was significantly higher than that in other ROI areas(P<0.05).After treatment,the β values of SMC and SMA on the affected hemisphere of the three groups were higher than before treatment(P<0.05),and the βvalues of SMC and SMA on the affected hemisphere in the r TMS group and the i TBS group were significantly higher than those in the control group(P<0.05),but there was no significant difference between the r TMS group and the i TBS group(P>0.05).There was no significant change in bilateral PFC before and after treatment(P>0.05).4.At rest,the result of brain functional connection strength between all ROIs after 3 weeks of treatment showed that: compared with the control group,the increase brain functional connection strength in the r TMS group were as flows: ipsilesional SMC and contralateral SMC;ipsilesional SMA and contralateral SMC,SMA,PFC;ipsilesional PFC and contralateral PFC(P<0.05);and the increase brain functional connection strength in the i TBS group were as flows: ipsilesional SMC and contralateral SMC,SMA,PFC,ipsilesional SMA;ipsilesional SMA and contralateral SMC,SMA,PFC,ipsilesional PFC;ipsilesional PFC and contralateral SMC;contralateral SMC and contralateral PFC(P<0.05).Among them,increase FC of ipsilesional SMC and contralateral SMC,SMA,ipsilesional SMA;ipsilesional SMA and contralateral SMC,SMA,PFC,ipsilesional PFC were significant(P<0.01).Compared with the r TMS group,the increase brain functional connection strength in the i TBS group were as flows: ipsilesional SMC and ipsilesional SMA;ipsilesional SMA and contralateral SMC(P<0.05).Among them,increase functional connection strength of ipsilesional SMC and ipsilesional SMA were significant(P<0.01).Conclusions:1.Both 10 Hz rTMS and iTBS can promote the recovery of lower limb motor balance function in stroke patients with lower limb dysfunction.2.10 Hz rTMS or iTBS can activate the SMC area and SMA area of the affected cerebral hemisphere,and the recovery of lower limb motor function might be related to the enhanced activation of the affected cerebral regions.3.Transcranial magnetic stimulation can enhance the functional connection strength between the regions of interest,and compared with r TMS,i TBS may be more able to promote the network connection strength of the regions of interest between the affected side and the unaffected side hemispheres.