| Backgroud and ObjectiveStroke is one of the main causes of acquired adult disability.The "golden age" of motor rehabilitation and nerve repair is within three months after stroke Neurorehabilitation treatment in the early stage of stroke can significantly improve the motor function and prognosis of the patients.As a new therapy strategy,repetitive transcranial magnetic stimulation(rTMS)has a promising application prospects in post-stroke motor rehabilitation.However,there is a dispute over the results of several studies on the viewpoint of rTMS treatment in the early stage of stroke.The mechanism study of rTMS treatment contributes to the resolution of the dispute Therefore,in the study,we intend to use multimodal fMRI to investigate the cerebral structural and functional changes induced by rTMS treatment at the early stage of stroke,and to explore the possible mechanism of rTMS treatment to regulate neuroplasticity and motor functional reorganizationMethodsSixty first-ever stroke patients with motor deficits were consecutively recruited The patients were randomized into three groups(high frequency group,low frequency group and sham stimulation group),and received rTMS for 5 consecutive days and the same routine medical treatment.Functional magnetic resonance imaging(fMRI)and the assessment of motor function score were respectiviely performed before and after rTMS treatment,and after 3 months of stroke onset.The following methods are used for multimodal fMRI evaluation(1)To investigate the effect of rTMS on resting-state functional connectivity(FC)of brain motor network in patients with motor deficit at the early stage of stroke,and the relationship between the alteration of FC and the improvement of motor function.(2)To investigate the effect of rTMS on brain microstructure(grey and white matter)in patients with motor deficit at the early stage of stroke by using diffusion kurtosis imaging(DKI),and the relationship between the alteration of brain microstructure and the improvement of motor function.(3)To investigate the effect of rTMS on the topological properties of brain motor execution network in patients with motor deficit at the early stage of stroke by using the method of graph theory,and the relationship between the alteration of topological properties and the improvement of motor function.Results(1)Compared with the sham stimulation group,high frequency and low frequency stimulation group demonstrated significantly increasing FCs between the ipsilateral primary motor cortex(M1)and other motor related brain regions after treatment,and the part of the FCs still kept significantly increasing at three month after rTMS.The changes in the functional connections of the ipsilesional M1-contralesional M1 and the ipsilesional M1-bilateral SMA after rTMS treatment were correlated with the improvement of motor function after treatment and at three month follow-up.(2)Compared with the real rTMS groups,the sham stimulation group showed the decreasing MK value and/or FA value and the increasing MD value in the ipsilesional precentral gyrus,the posterior limb of the ipsilesional internal capsule and transcallosal motor fiber.The MK and FA value changes of the ipsilesional precentral gyrus,transcallosal motor fiber and the MK value change of the posterior limb of the ipsilesional internal capsule after treatment were correlated with the improvement of motor function after treatment.The MK change of the posterior limb of the ipsilesional internal capsule after treatment was correlated with the improvement of motor function at three month follow-up.(3)Compared with the sham stimulation group,the high frequency group showed that the brain motor execution network more rapidly drifted to the randomization pattern after treatment.Real rTMS groups demonstrated an increasing trend in the degree centrality(DC)and node efficiency(Ne)of several nodes,including the bilateral M1.The changes in the global parameters(Cp,Lp,Eg and Eloc)and the node parameters(DC and Ne of the bilateral M1)after treatment were correlated with the improvement of motor function after treatment.The changes of DC and Ne of the ipsilesional M1 after treatment were correlated with the improvement of motor function at three month follow-up.ConclusionsIn the early stage of stroke,rTMS promotes the reorganization of motor function network by regulating the functional connectivity of motor network.The microstructural alteration of the motor related brain regions induced by rTMS may help to maintain the integrity of the ipsilesional corticospinal tract and transcallosal motor fiber,and to promote the recovery of motor function.rTMS may regulate the global and nodal topology properties of the motion execution network.The high frequency rTMS accelerate brain motor execution network to drift more rapidly to randomization pattern,which facilitates the global and local information exchange and integration,and facilitates the reorganization of motor functional networks.This study provides evidence of neuroimaging in the treatment rTMS for motor deficit in the early stage of stroke. |
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