Objective To systematically review the efficacy of low-frequency repetitive transcranial magnetic stimulation (rTMS) compared with sham therapy for the treatment of major depressive disorder. Methods The Cochrane Library, Medline, EMbase, CBMdisk, CNKI and VIP were searched through computer from 1985 to 2011. The review included RCTs comparing the treatment efficacy of low-frequency rTMS located on right dorsolateral prefrontal cortex (DLPFC) with sham stimulation in the patients suffering major depressive disorder. The quality of the included RCTs was strictly evaluated and the data were extracted by two reviewers independently. The extracted data were analyzed by RevMan 4.2. Results Among seven double-blinded RCTs involving 234 patients included, 1 was A level in quality, 5 were B level, and 1 was C level according to the outcomes of quality evaluation. The results of Meta-analysis indicated that low frequency rTMS was superior to sham stimulation in remission rates after two weeks’ treatment (RR=3.11, 95%CI 1.56 to 6.19). Additionally, low frequency rTMS was lower than the sham stimulation in the scores of HDRS and MADRS (WMD= –6.41, 95%CI –9.32 to –3.50, and WMD= –5.27, 95%CI –9.08 to –1.46, respectively). But no significant difference in response rates between the low prequency rTMS group and the sham group was found (RR=1.72, 95%CI 0.74 to 4.01). There were no severe and intolerable side effects reported in these seven studies. Conclusion The low frequency rTMS as a non-invasive and safe technique may appear to be effective for the treatment of major depressive disorder according to the positive results but the conclusion is not definite because of negative results. This review suggests that parameters could be sited as frequency: 1 Hz, intensity: 90%-110% motor threshold (MT), location: right DLPFC and duration: 2 weeks. Nevertheless, further multicenter and high quality studies are needed before it is used as a first-line treatment for major depressive disorder.
We investigated the baseline brain activity level in patients with major depressive disorder (MDD) by amplitude of low-frequency fluctuation (ALFF) based on resting-state functional MRI (fMRI). We examined 13 patients in the MDD group and 14 healthy volunteers in the control group by resting-state fMRI on GE Signa 3.0T. We calculated and compared the ALFF values of the two groups. In the MDD group, ALFF values in the right medial prefrontal were higher than those in control group, with statistically significant differences (P<0.001). ALFF values in the left parietal in the MDD group were lower than those in control group with statistically significant differences (P<0.001). This resting-state fMRI study suggested that the alteration brain activity in the right medial prefrontal and left parietal ALFF contributed to the understanding of the pathophysiological mechanism of MDD patients.
This paper analyzed literatures on the specificity study of electroencephalogram (EEG) in the diagnosis of depression since 2010 to 2020, summarized the recent research directions in this field and prospected the future research hotspots at home and abroad. Based on databases of China National Knowledge Infrastructure (CNKI) and the core collection of Web of Science (WOS), CiteSpace software was used to analyze the relevant literatures in this research field. The number of relevant literatures, countries, authors, research institutions, key words, cited literatures and periodicals related to this research were analyzed, respectively, to explore research hotspots and development trends in this field. A total of 2 155 articles were included in the WOS database. The most published institution was the University of Toronto, the most published country was the United States, China occupied the third place, and the hot keywords were anxiety, disorder, brain and so on. A total of 529 literatures were included and analyzed in CNKI database. The institution with the most publications was the Mental Health Center of West China Hospital of Sichuan University, and the hot keywords were EEG signal, event-related potential, convolutional neural network, schizophrenia, etc. This study finds that EEG study of depression is developing rapidly at home and abroad. Research directions in the world mainly focus on exploring the characteristics of spontaneous EEG rhythm and nonlinear dynamic parameters during sleep in depressed patients. In addition, synchronous transcranial magnetic stimulation (TMS) and EEG technologies also attract much attention abroad, and the future research hotspot will be on the mechanism of EEG on patients with major depression. Domestic research directions mainly focus on the classification of resting EEG and the control study of resting EEG power spectrum entropy in patients with schizophrenia and depression, and future research hotspot is the basic and clinical EEG study of depressed patients complicated with anxiety.
Electroconvulsive therapy (ECT) is an interventional technique capable of highly effective neuromodulation in major depressive disorder (MDD), but its antidepressant mechanism remains unclear. By recording the resting-state electroencephalogram (RS-EEG) of 19 MDD patients before and after ECT, we analyzed the modulation effect of ECT on the resting-state brain functional network of MDD patients from multiple perspectives: estimating spontaneous EEG activity power spectral density (PSD) using Welch algorithm; constructing brain functional network based on imaginary part coherence (iCoh) and calculate functional connectivity; using minimum spanning tree theory to explore the topological characteristics of brain functional network. The results show that PSD, functional connectivity, and topology in multiple frequency bands were significantly changed after ECT in MDD patients. The results of this study reveal that ECT changes the brain activity of MDD patients, which provides an important reference in the clinical treatment and mechanism analysis of MDD.