Functional MRI Study Of Repeated Transcranial Magnetic Stimulation For Post-Stroke Depression

Objective:To explore the efficacy of High-frequency rTMS in the treatment of ischemic PSD and the clinical features of brain remoding mechanism.We use High-frequency rTMS to traet the ischemic PSD.Assessing depresion by Hamilton Depression Scale(HAMD-17),observing brain changes by resting state functional magnetic resonance.imaging(rs-fMRI).Methods:According to the imaging diagnostic and Hamilton depression criteria,32 patients who are diagnosed ischemic PSD as well as tested without cognitive impairment by Montreal Cognitive Assessment(MOCA≥26)are selected.,19 patients(11 males and females)are divided into experimental group and 17 patients(9 males and 8 females)in the control group by the random number table.Both ware given conventional drug of stroke,psychological counseling and comprehensive rehabilitation trainings on the day of admission.The experimental group is given rTMS with a frequency of 5HZ and a magnetic field strength of 110%MT from the start of the experiment.The stimulation site is the Dorsolateral prefrontal cortex(DLPFC),20 mins/time,once daily,5 days/week,a total of 4 weeks.The control group is given the same site and fake stimulation when the power cord is disconnected.recoding the side reaction.the resting state functional magnetic resonance imaging are performed before and after the two groups of patients.All imaging data are based on the Metlab 2013a platform,which is preprocessed and calculated by researchers using DPARSF software.At first,We measure the whole brain Reho value and fALFF value before and after the experiment in both groups and extract the value of the default network network(DMN)by two-sample t-test for statistical difference,Secondly,we define the medial prefrontal cortex(mPFC)and the posterior cingulate cortex(PCC)as the regional of intrest(ROI),and measure the ROI with the Whole brain dynamic function of the connection difference by dynamic BC software.At the end of the experiment,we eliminated the cases of disassembly.The experimental group completed 16 cases,and the control group completed 16 cases.The SPM8 software is used to perform the two-sample t-test on the experimental group and the control group,the comparison between groups and the more statistically significant regions in the group and report the corresponding voxel size,peak and coordinate;Finally,the correlation between the HAMD-17 scale with the Reho value and the FALFF value and the ROI’S dFC value of the experimental group is analyzed.Results:1.The HAMD-17 score was lower in all patients than before(P<0.05).The experimental group had more significant reduction than the control group(P<0.01).No subjects experienced dizziness,epilepsy,and other discomfort during the experiment.2.Compared with the control group,the experimental group had significant changes in the whole brain Reho and fALFF,and the left side of the brain had more Reho’s elevation than the right side.Among them,the most significant brain regions of Reho increased in the left frontal lobe,the inferior lobules,and some In the temporal lobe(P<0.05),the areas with significant increase in fALFF were left frontal lobe,anterior middle gyrus,anterior precuneus,parietal lobe,and inferior temporal gyrus(P<0.05).These regions were highly consistent with the anatomical localization of DMN neurons.Further information on the separation of DMN showed that Reho and fALFF were significantly higher than those in the control group(P<0.05),and the main concentrated area was in the left frontal lobe.The dynamic functional connection(dFC)study found that after treatment,the experimental group was more connected with the control group ROI1(mPFC)and the brain’s left inferior frontal gyrus,cingulate gyrus,middle temporal gyrus,anterior wedge,etc.Decreased connection in the next time;ROI2(PCC)increased in connection with the inferior parietal lobe,central posterior gyrus,tongue gyrus,left inferior frontal gyrus,left superior temporal gyrus,and superior left superior temporal gyrus.No statistically significant weakened regions were observed(the above regions were corrected by Alphsim.P<0.05).3.Pearson correlation analysis was performed on the Reho,fALFF,dFC,and HAMD scores in the DMN before and after the trial in the two groups.The results showed that before the experiment,there was no correlation between the index of the experimental group and the control group and the HAMD score.After treatment,the control group No correlations were found,but in the experimental group Reho(r=-0.51,P=0.04),fALFF(r=-0.55,P=0.03),dFC(ROI1r=-0.57,P=0.02),ROI2 r=-0.52,p=0.04)was negatively correlated with HAMD.Conclusion:1.It just like drugs,rehabilitation training,and psychological interventions,high-frequency rTMS is reliable for PSD and has no significant complications.2.The default network neuronal activity has a predictive function for the therapeutic effect and prognosis.of PSD,and is of great significance for the study of the mechanism of neural remodeling of PSD with high frequency rTMS.The prefrontal lobe serves as a stimulus target,and at the same time it is the internal core node of the default network.Together with the posterior cingulate gyrus,it plays an important role in the PSD brain function reconstruction mechanism.3.The left high-frequency rTMS causes a functional connection between the nodes within the default network.Activation of the mode transition may be another mechanism for neural remodeling of the PSD recovery.Due to the limited number of samples in this study,this kind of lateralized functional connectivity enhancement still needs more multi-center large sample studies to further support.Functional magnetic resonance imaging as a means of observing the changes of brain function of PSD provides a broad research space for the study of the occurrence,development and prognosis of PSD.