Effects Of Repetitive Transcranial Magnetic Stimulation On Upper Limb Function In Patients After Cerebral Infarction

Stroke is the main cause of disability,55% ～ 75% of stroke patients still have upper limb dysfunction after 3-6 months,which seriously affects daily life and work.Physical therapy represents an essential tool for motor recovery,but its effectiveness is limited.Repetitive transcranial magnetic stimulation(rTMS)is a non-invasive stimulation to induce electrical currents in the brain tissues.Currently,rTMS is being explored as a novel therapy in modulating cortical excitability to improve motor functions in stroke patients.Its effect mainly depends on the frequency,intensity and pattern of stimulation.The interhemispheric competition model proposes that motor deficits in patients after stroke are due to a reduced output from the affected hemisphere and excess transcallosal inhibition of the affected hemisphere from the unaffected hemisphere.Research has demonstrated that high-frequency rTMS over the affected hemisphere can improved the motor function of the paretic hand by increasing the excitability of the affected motor cortex.Low-frequency rTMS over the unaffected hemisphere decreased the excitability of the unaffected hemisphere and improved the motor function of the paretic hand in patients after stroke.Objective The purpose of this study is to observe the effects of three types of repetitive transcranial magnetic stimulation(rTMS)with high frequency,low frequency and combined low and high frequency on motor function of upper limb in patients after cerebral infarction.This study can provide the scientific basis of rTMS application for therapists.Methods During the period of December 2017 to May 2019,216 patients with ischemic stroke from department of Rehabilitation Medicine,the Affiliated Zhongda Hospital of Southeast University and its sub-center were enrolled in this study,all patients satisfy the inclusion and exclusion criteria.They were randomly assigned to four groups,including low-frequency group(LF),high-frequency group(HF),combined high and low frequency group(HF-LF)and sham group with54 in each.All the patients in four groups received conventional medical treatment and rehabilitation training.In addition,the patents in HF-LF group received 1Hz rTMS over the contralesional hemisphere.Then,10 Hz rTMS was applied to the ipsilesional hemisphere.The patients in LF group received 1Hz rTMS over the contralesional hemisphere,then,10 Hz sham rTMS was applied to the ipsilesional hemisphere.The patents in HF group received 1Hz sham rTMS stimulation over the contralesional hemisphere,then,10 Hz rTMS was applied to the ipsilesional hemisphere.The sham group received sham stimulation at the same sites in the same order as the LF-HF rTMS group.All therapy were conducted 6 days per week for 4 weeks.Before and after 4 weeks,the motor evoked potential cortical latency(CL),the threshold of rest motor and the central motor conduction time(CMCT)in affected brain area were measured.The upper limb motor function was evaluated by the Fugl-Meyer upper limb extremity assessment(FMA-UE),the Hong Kong edition of functional test for the hemiplegic upper extremity(FTHUE-HK)and the modified Barthel index(MBI).Results(1)Before intervention there was no signification difference between the four groups in terms of all the assessment.There was signification difference between the ipsilesional and contralesional in scores of CL 、RMT and CMCT for every group(p<0.05).(2)After 4weeks of treatment,the scores of CL,RMT,CMCT all improved significantly in four groups compared to those before treatment(p<0.05).HF-LF group,HF group and LF group all improved significantly in scores of CL,RMT and CMCT than those of sham group.Group HF-LF showed more shorter in CMCT scores and more lower in RMT scores than those of group HF and group LF.There was no significant difference between group HF and group LF in scores of CL,RMT and CMCT.(3)After 4 weeks of treatment,the scores of FMA-UE,FTHUE-HK and MBI all improved significantly in four groups compared to those before treatment(p<0.05).Group HF-LF improved significantly better than other three groups in terms of any of the assessments(p<0.05).The FMA-UE scores of HF group and LF improved significant better than those of sham group.There was no significant difference between group HF and group LF in scores of FMA-UE,FTHUE-HK and MBI.Conclusion(1)This study indicates that ipsilesional corticomotor excitability was lower than contralesional corticomotor excitability after stroke.(2)Repetitive transcranial magnetic stimulation with high frequency,low frequency and combined low and high frequency all could improve excitability of cerebral cortex of the affected brain area and promote the recovery of upper limb motor function.Additionally,combined low and high frequency rTMS had the most significant effect.However,there was no significant difference in the treatment effect between the group of high frequency rTMS and low frequency rTMS.