Transcranial direct current stimulation (tDCS) in unipolar vs. bipolar depressive disorder
ABSTRACT Transcranial direct current stimulation (tDCS) is a non-invasive method for brain stimulation. Although pilot trials have shown that tDCS yields promising results for major depressive disorder (MDD), its efficacy for bipolar depressive disorder (BDD), a condition with high prevalence and poor treatment outcomes, is unknown. In a previous study we explored the effectiveness of tDCS for MDD. Here, we expanded our research, recruiting patients with MDD and BDD. We enrolled 31 hospitalized patients (24 women) aged 30-70 years 17 with MDD and 14 with BDD (n = 14). All patients received stable drug regimens for at least two weeks before enrollment and drug dosages remained unchanged throughout the study. We applied tDCS over the dorsolateral prefrontal cortex (anodal electrode on the left and cathodal on the right) using a 2 mA-current for 20 min, twice-daily, for 5 consecutive days. Depression was measured at baseline, after 5 tDCS sessions, one week later, and one month after treatment onset. We used the scales of Beck (BDI) and Hamilton-21 items (HDRS). All patients tolerated treatment well without adverse effects. After the fifth tDCS session, depressive symptoms in both study groups diminished, and the beneficial effect persisted at one week and one month. In conclusion, our preliminary study suggests that tDCS is a promising treatment for patients with MDD and BDD.2.
SourceAvailable from: Leonor J Romero Lauro[Show abstract] [Hide abstract]
ABSTRACT: Despite transcranial direct current stimulation (tDCS) is increasingly used in experimental and clinical settings, its precise mechanisms of action remain largely unknown. At a neuronal level, tDCS modulates the resting membrane potential in a polarity-dependent fashion: anodal stimulation increases cortical excitability in the stimulated region, while cathodal decreases it. So far, the neurophysiological underpinnings of the immediate and delayed effects of tDCS, and to what extent the stimulation of a given cerebral region may affect the activity of anatomically connected regions, remain unclear. In the present study, we used a combination of Transcranial Magnetic Stimulation (TMS) and Electroencephalography (EEG) in order to explore local and global cortical excitability modulation during and after active and sham tDCS. Single pulse TMS was delivered over the left posterior parietal cortex (PPC), before, during, and after 15 min of tDCS over the right PPC, while EEG was recorded from 60 channels. For each session, indexes of global and local cerebral excitability were obtained, computed as global and local mean field power (Global Mean Field Power, GMFP and Local Mean Field Power, LMFP) on mean TMS-evoked potentials (TEPs) for three temporal windows: 0-50, 50-100, and 100-150 msec. The global index was computed on all 60 channels. The local indexes were computed in six clusters of electrodes: left and right in frontal, parietal and temporal regions. GMFP increased, compared to baseline, both during and after active tDCS in the 0-100 msec temporal window. LMFP increased after the end of stimulation in parietal and frontal clusters bilaterally, while no difference was found in the temporal clusters. In sum, a diffuse rise of cortical excitability occurred, both during and after active tDCS. This evidence highlights the spreading of the effects of anodal tDCS over remote cortical regions of stimulated and contralateral hemispheres.Cortex 06/2014; 58C:99-111. DOI:10.1016/j.cortex.2014.05.003 · 6.04 Impact Factor
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ABSTRACT: The interest in non-invasive brain stimulation techniques is increasing in recent years. Among these techniques, transcranial direct current stimulation (tDCS) has been the subject of great interest among researchers because of its easiness to use, low cost, benign profile of side effects and encouraging results of research in the field. This interest has generated several studies and randomized clinical trials, particularly in psychiatry. In this review, we provide a summary of the development of the technique and its mechanism of action as well as a review of the methodological aspects of randomized clinical trials in psychiatry, including studies in affective disorders, schizophrenia, obsessive compulsive disorder, child psychiatry and substance use disorder. Finally, we provide an overview of tDCS use in cognitive enhancement as well as a discussion regarding its clinical use and regulatory and ethical issues. Although many promising results regarding tDCS efficacy were described, the total number of studies is still low, highlighting the need of further studies aiming to replicate these findings in larger samples as to provide a definite picture regarding tDCS efficacy in psychiatry.03/2015; 5(1):88-102. DOI:10.5498/wjp.v5.i1.88
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ABSTRACT: Background: Typically, transcranial direct current stimulation (tDCS) treatments for depression have used bifrontal montages with anodal (excitatory) stimulation targeting the left dorsolateral prefrontal cortex (DLPFC). There is limited research examining the effects of alternative electrode montages. Objective/hypothesis: This pilot study aimed to examine the feasibility, tolerability and safety of two alternative electrode montages and provide preliminary data on efficacy. The montages, Fronto-Occipital (F-O) and Fronto-Cerebellar (F-C), were designed respectively to target midline brain structures and the cerebellum. Methods: The anode was placed over the left supraorbital region and the cathode over the occipital and cerebellar region for the F-O and F-C montages respectively. Computational modelling was used to determine the electric fields produced in the brain regions of interest compared to a standard bifrontal montage. The two montages were evaluated in an open label study of depressed participants (N=14). Mood and neuropsychological functioning were assessed at baseline and after four weeks of tDCS. Results: Computational modelling revealed that the novel montages resulted in greater activation in the anterior cingulate cortices and cerebellum than the bifrontal montage, while activation of the DLPFCs was higher for the bifrontal montage. After four weeks of tDCS, overall mood improvement rates of 43.8% and 15.9% were observed under the F-O and F-C conditions, respectively. No significant neuropsychological changes were found. Limitations: The clinical pilot was open-label, without a control condition and computational modelling was based on one healthy participant. Conclusions: Results found both montages safe and feasible. The F-O montage showed promising antidepressant potential. Crown CopyrightJournal of Affective Disorders 06/2014; 167C:251-258. DOI:10.1016/j.jad.2014.06.022 · 3.71 Impact Factor