Abstract
Background: The difficulty in timely evaluating 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 identify predictive biological markers for patient response.Methods: Thirty drug-naïve MDD patients (20 females and 10 males) were enrolled in this study. All the 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 paired t-test. Spearman correlation coefficients were calculated to identify the relationships between the improvement of depression and anxiety symptoms and microstate parameters.Results: The mean duration (69.67 ± 10.33 vs. 64.00 ± 7.70, p < 0.001) and occurrence (4.06 ± 0.69, vs. 3.69 ± 0.70, p = 0.002) of microstate B decreased significantly after treatment. The proportion of microstate B also decreased (27.53 ± 5.81, vs. 23.23 ± 4.61, p < 0.001), while the occurrence of microstate A increased after treatment. A significant negative correlation was found between the change of score of Hamilton Rating Scale for Anxiety and the increase of the occurrence of microstate A (r = −0.431, p < 0.05) after 2 weeks of treatment. The reduction of the duration of microstate B was found to be predictive of patient response to antidepressants after 3 months.Conclusion: This study explored the relationship between changes of EEG microstates and patient response to antidepressants. Depression symptoms might be associated with the duration of microstate B and anxiety symptoms related to the occurrence of microstate A. Therefore, the duration of microstate B and the occurrence of microstate A are potential biological markers for MDD patients' early response and further clinical outcomes.
Highlights
Major depressive disorder is a prevalent psychiatric illness and one of the leading causes of disability across the world [1]
While many studies that used functional magnetic resonance imaging have shown that major depressive disorder (MDD) is characterized by abnormal functional connections and neural activities [4], fMRI lacks the temporal resolution needed to track the dynamics of brain activities
We aim to identify predictive biological markers for patients’ early response to treatment through exploring changes in EEG microstates in patients at the acute stage of MDD, in order to provide a clinical guidance for subsequent treatment for this disease
Summary
Major depressive disorder is a prevalent psychiatric illness and one of the leading causes of disability across the world [1]. As many studies showed that the improve of depression is related to the recovery of brain network function [3], it is crucial to identify predictive biomarkers for clinical efficacy at the early stage of treatment with antidepressants. Spontaneous activities of various large-scale cortical networks can be reflected in macroscopic EEG potentials [5, 6] The abnormality in this brain functional connectivity is associated with MDD [7], and can be affected by treatments. The difficulty in timely evaluating patient response to antidepressants has brought great challenge to the treatment of major depressive disorder (MDD). The present study aims to evaluate the relationship between EEG microstate parameters and MDD symptoms before and after treatment to identify predictive biological markers for patient response
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