Changes Of EEG Microstates After Treatment In Drug Na(?)ve MDD Patients And Correlation With Symptom Change

Background: The difficulty in timely evaluation of patient response to antidepressants has brought great challenge to the treatment of major depressive disorder(MDD).Some studies found that the electroencephalogram(EEG)microstates might be a reliable marker to evaluate patient response to treatment.The present study aims to evaluate the relationship between EEG microstate parameters and MDD symptoms before and after treatment to explore correlations between patient response and changes in EEG microstates after treatment.Methods: Thirty first-episode drug-na?ve MDD patients(20 females and 10 males)were enrolled in this study.All patients received effective dosages of selective serotonin reuptake inhibitors,and EEG recordings were collected at baseline and 2 weeks of treatment.Brain activities during the eyes-closed state were recorded using 64-channel electroencephalography,and the patients’ microstates were clustered into four maps according to their topography(labeled A,B,C,and D).The differences of EEG microstates before and after treatment were compared using repeated measures anova.Pearson correlation coefficients were calculated to identify the relationships between the change of depression and anxiety symptoms after 3 months’ treatment and microstate parameters.Results: The occurrence(F=18.06,P<0.001)and coverage(F=10.61,P=0.003)of microstate A increased significantly after treatment.While the mean duration(F=12.39,P=0.001),occurrence(F=10.10,P=0.004)and coverage(F=12.48,P=0.001)of microstate B decreased aftertreatment.Transition probabilities between microstates A-D and A-C increased significantly after treatment,while transition probabilities between microstates B and C decreased.A significant negative correlation was found between the change of score of Hamilton Depression Rating Scale after 3 months and the increase of the duration of microstate B after 2weeks of treatment(r=-0.37,P=0.042).The increase of the duration(r=0.41,P=0.024),occurrence(r=0.45,P=0.013),and proportion(r=0.52,P=0.003)of microstate C was found to be positively correlated with HAMA reduction after 3 months.Conclusion: This study explored the relationship between changes of EEG microstatesand patient response to antidepressants.Microstates A and C are potential biological markers for MDD patients’ early response and further clinical outcomes and may be associated with treatment response while microstate B may be associated with depression symptom change.