Clinical Efficacy Of TECAS For Mild-to-Moderate Major Depressive Disorder And Its Brain Mechanism A Resting-state FMRI Study

Objective: To investigate the treatment responsivity and neurological effects of TECAS compared to escitalopram,a commonly used medication for depression.Methods: From November 2019 to January 2022,patients with mild-tomoderate major depressive disorder(MDD)and demographically-matched healthy controls(HCs)were recruited at the Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University.Totally 50 patients with mild-to-moderate MDD(29 in the TECAS group and 21 in the escitalopram group)and 49 HCs were enrolled in this study.Patients with MDD received resting-state f MRI scans and the Montgomery-Asberg Depression Rating Scale(MADRS),Hamilton Depression Rating Scale(HAMD)and Hamilton Anxiety Rating Scale(HAMA)before and after 8-week treatment,and the side effects were recorded by the Side Effects Rating Scale(SERS).While HCs only received one resting-state f MRI scan and the above clinical scales assessment,but without any intervention.Part I: Comparing the antidepressant efficacy of TECAS and escitalopramFirstly,demographic information and clinical scales(including MADRS,HAMD and HAMA)were compared between depressed patients at baseline and HCs.Secondly,the demographic information,baseline level of clinical scales and differences of MADRS,HAMD and HAMA before and after treatment were analyzed between TECAS group and Escitalopram group.Thirdly,the difference of the Side Effects Rating Scale(SERS)between the two treatments were compared.Part II: Exploring the neurological effects of TECAS by independent component analysis(ICA)Firstly,brain networks were screened by ICA based on the resting-state f MRI data.Secondly,the functional connectivity(FC)of intra-and inter-network between patients with mild-to-moderate MDD at baseline and HCs were analyzed.Thirdly,the FC of intra-and inter-network at TECAS or escitalopram group before and after treatment were compared separately,so as to compare the brain mechanisms between the two treatments.Fourthly,the correlation between the above FC changes and corresponding clinical scale scores before and after treatment in TECAS or escitalopram group was analyzed.f MRI preprocessing,brain network screening based on ICA and subsequent statistics were all completed based on SPM12.0,restplus and GIFT software of MATLAB.Results:Part I:(1)Subjects enrolled: Totally 49 HCs and 50 patients with mild-tomoderate MDD completed the resting-state f MRI scan and clinical scale evaluation.In TECAS group,there were 29 cases recruited,2 cases fell off,and27 cases completed assessment pre-and post-treatment;while there were 21 cases recruited,3 cases fell off,and 18 cases completed the whole assessment at escitalopram group.(2)Demographic and baseline information: there were no obvious differences in age and sex between the HCs and mild-to-moderate depression(P>0.05),but there were different in education level(P<0.05),and no extreme difference of IQ scores between the two groups(P>0.05);besides,there were no significant differences for age,sex and education level between TECAS group and escitalopram group(P>0.05).(3)Efficacy evaluation: TECAS and escitalopram could improve the depressive symptoms of MDD,and there were no significant differences in the reduction rates of MADRS,HAMD and HAMA after both treatments,though there are some differences in response rates calculated by these scales.(4)SERS: No serious adverse effects occurred during the TECAS or escitalopram treatment;there was no significant difference in SERS between them(P>0.05),and the slightly skin damage in the stimulation area was the occasionally side effects of TECAS.Part II:(1)ICA: TECAS and escitalopram both modulated the default mode network(DMN),right frontoparietal network(RFPN),dorsal attention network(DAN)and primary visual network(PVN).The increased FC of PVN-RFPN was reduced after both treatments.However,the FC of DMN-RFPN and DMNDAN were increased after TECAS treatment,while they were decreased after another treatment.Moreover,there were only changes in FC of the ventral attention network and the left frontoparietal network after escitalopram treatment.(2)Correlation analysis: there was no significant relationship between the abnormal brain network and corresponding clinical scale scores after TECAS or escitalopram treatment.Conclusion:(1)TECAS could effectively relieve depressive symptoms which is similar to that of escitalopram;there were no serious adverse situations during the treatment of TECAS,and the slightly skin damage in the stimulation area was the occasionally side effects of TECAS.(2)TECAS and escitalopram induced different brain networks,such as the FC of DMN-RFPN and DMN-DAN increased after TECAS treatment,while that decreased after escitalopram.However,the increased FC of PVN-RFPN in MDD was decreased after the both treatments,which may suggest the existence of common brain mechanism.(3)By reviewing the brain networks,we found that: DMN plays an important role in the antidepressant efficacy of TECAS;TECAS could help to regulate brain control system dysfunction,and improve memorial and emotional symptoms.(4)Large-scale randomized controlled studies should be carried out to fully evaluate the treatment responsivity and neurological effects of TECAS.