Clinical trial design in non-invasive brain stimulation psychiatric research

Efficacy of non-invasive brain stimulation interventions in reducing smoking frequency in patients with nicotine dependence: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Nicotine is a highly addictive substance in tobacco products that dysregulates several neurotransmitters in the brain and impairs executive function. Non-invasive brain stimulation (NIBS) methods such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are promising treatments for nicotine dependence. We investigated the efficacy and acceptability of NIBS in managing smoking cessation through a systematic review and network meta-analysis (NMA).

METHODS

We conducted a systematic review to identify randomized controlled trials (RCTs) that investigated the efficacy of NIBS for smoking cessation. All pairwise meta-analyses and NMA procedures were conducted using random-effects and frequentist models. The co-primary outcomes were (1) the change in number of cigarettes smoked per day (change in frequency of smoking) in patients with nicotine dependence after NIBS and (2) acceptability (the dropout rate). The effect sizes for co-primary outcomes of change in frequency of smoking and acceptability were assessed according to standardized mean difference (SMD) and odds ratio, respectively.

RESULTS

Twelve RCTs with 710 participants (mean age: 44.2 years, 31.2% female) were included. Compared with the sham control, 10-Hz rTMS over the left dorsolateral prefrontal cortex (DLPFC) was associated with the largest changes in smoking frequency [SMD = -1.22, 95% confidence interval (95% CI) = -1.77 to -0.66]. The 2-mA bifrontal tDCS (SMD = -0.97, 95% CI = -1.32 to -0.62) and 10-Hz deep rTMS over the bilateral DLPFC with cue provocation (SMD = -0.77, 95% CI = -1.20 to -0.34) were associated with a significantly larger decrease in smoking frequency versus the sham. None of the investigated NIBSs was associated with dropout rates significantly different from those of the sham control groups.

CONCLUSION

Prefrontal non-invasive brain stimulation interventions appear to reduce the number of cigarettes smoked with good acceptability.

Neurostimulation and Reach-to-Grasp Function Recovery Following Acquired Brain Injury: Insight From Pre-clinical Rodent Models and Human Applications

Reach-to-grasp is an evolutionarily conserved motor function that is adversely impacted following stroke and traumatic brain injury (TBI). Non-invasive brain stimulation (NIBS) methods, such as transcranial magnetic stimulation and transcranial direct current stimulation, are promising tools that could enhance functional recovery of reach-to-grasp post-brain injury. Though the rodent literature provides a causal understanding of post-injury recovery mechanisms, it has had a limited impact on NIBS protocols in human research. The high degree of homology in reach-to-grasp circuitry between humans and rodents further implies that the application of NIBS to brain injury could be better informed by findings from pre-clinical rodent models and neurorehabilitation research. Here, we provide an overview of the advantages and limitations of using rodent models to advance our current understanding of human reach-to-grasp function, cortical circuitry, and reorganization. We propose that a cross-species comparison of reach-to-grasp recovery could provide a mechanistic framework for clinically efficacious NIBS treatments that could elicit better functional outcomes for patients.

Effects of Transcranial Direct Current Stimulation (tDCS) and Approach Bias Modification (ABM) training on food cravings in people taking antipsychotic medication

BACKGROUND

Antipsychotic drug-induced weight gain puts individuals with schizophrenia at increased cardiometabolic risk. As a potential intervention for this problem, we describe the theoretical background and a protocol for a feasibility randomised controlled trial (RCT) of approach bias modification (ABM) training combined with real versus sham (placebo) transcranial direct current stimulation (tDCS). The primary aim of this trial is to obtain information that will guide decision making and protocol development in relation to a future large-scale RCT of ABM and tDCS in this group of participants. Second, the study will assess the preliminary efficacy of ABM + tDCS in reducing food cravings in people who take antipsychotic medication.

METHODS

Thirty adults with a DSM-V diagnosis of schizophrenia or schizoaffective disorder treated with anti-psychotic medication will be randomly allocated to receive five sessions that will combine ABM and real or sham tDCS, in a parallel group design. In this feasibility study, a broad range of outcome variables will be examined. Measures will include food craving, psychopathology (e.g. symptoms of schizophrenia and depression), neuropsychological processes (such as attentional bias and impulsiveness), and the tolerability and acceptability of tDCS. The feasibility of conducting a large-scale RCT of ABM + tDCS and appropriateness of tDCS as a treatment for antipsychotic drug-induced weight gain will be evaluated by assessment of recruitment and retention rates, acceptability of random allocation, blinding success (allocation concealment), completion of treatment sessions and research assessments (baseline, post-treatment and follow-up).

DISCUSSION

The effect sizes generated and other findings from this trial will inform a future large-scale RCT with respect to decisions on primary outcome measures and other aspects of protocol development. In addition, results from this study will provide a preliminary indication of the efficacy of ABM + tDCS treatment for antipsychotic drug-induced weight gain.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN13280178. Registered on 16 October 2018.

Trends of Repetitive Transcranial Magnetic Stimulation From 2009 to 2018: A Bibliometric Analysis

Repetitive transcranial magnetic stimulation (rTMS) technology, which is amongst the most used non-invasive brain stimulation techniques currently available, has developed rapidly from 2009 to 2018. However, reports on the trends of rTMS using bibliometric analysis are rare. The goal of the present bibliometric analysis is to analyze and visualize the trends of rTMS, including general (publication patterns) and emerging trends (research frontiers), over the last 10 years by using the visual analytic tool CiteSpace V. Publications related to rTMS from 2009 to 2018 were retrieved from the Web of Science (WoS) database, including 2,986 peer-reviewed articles/reviews. Active authors, journals, institutions, and countries were identified by WoS and visualized by CiteSpace V, which could also detect burst changes to identify emerging trends. GraphPad Prism 8 was used to analyze the time trend of annual publication outputs. The USA ranked first in this field. Pascual-Leone A (author A), Fitzgerald PB (author B), George MS (author C), Lefaucheur JP (author D), and Fregni F (author E) made great contributions to this field of study. The most prolific institution to publish rTMS-related publications in the last decade was the University of Toronto. The journal Brain Stimulation published most papers. Lefaucheur et al.'s paper in 2014, and the keyword "sham controlled trial" showed the strongest citation bursts by the end of 2018, which indicates increased attention to the underlying work, thereby indicating the research frontiers. This study reveals the publication patterns and emerging trends of rTMS based on the records published from 2009 to 2018. The insights obtained have reference values for the future research and application of rTMS.

Association of BDNF, HTR2A, TPH1, SLC6A4, and COMT polymorphisms with tDCS and escitalopram efficacy: ancillary analysis of a double-blind, placebo-controlled trial

OBJECTIVE

We investigated whether single nucleotide polymorphisms (SNPs) associated with neuroplasticity and activity of monoamine neurotransmitters, such as the brain-derived neurotrophic factor (BDNF, rs6265), the serotonin transporter (SLC6A4, rs25531), the tryptophan hydroxylase 1 (TPH1, rs1800532), the 5-hydroxytryptamine receptor 2A (HTR2A, rs6311, rs6313, rs7997012), and the catechol-O-methyltransferase (COMT, rs4680) genes, are associated with efficacy of transcranial direct current stimulation (tDCS) in major depression.

METHODS

Data from the Escitalopram vs. Electrical Current Therapy for Treating Depression Clinical Study (ELECT-TDCS) were used. Participants were antidepressant-free at baseline and presented with an acute, moderate-to-severe unipolar depressive episode. They were randomized to receive escitalopram/tDCS-sham (n=75), tDCS/placebo-pill (n=75), or placebo-pill/sham-tDCS (n=45). General linear models assessed the interaction between treatment group and allele-wise carriers. Additional analyses were performed for each group and each genotype separately.

RESULTS

Pairwise group comparisons (tDCS vs. placebo, tDCS vs. escitalopram, and escitalopram vs. placebo) did not identify alleles associated with depression improvement. In addition, exploratory analyses also did not identify any SNP unequivocally associated with improvement of depression in any treatment group.

CONCLUSION

Larger, combined datasets are necessary to identify candidate genes for tDCS response.

Transcranial direct current stimulation for the treatment of major depressive disorder: A meta-analysis of randomized controlled trials

Major depressive disorder (MDD) is a common and refractory mental disorder. Although antidepressant drugs may be effective for treating MDD, a number of patients do not improve with pharmacologic treatment. Novel therapeutic strategies which are safer and more effective are of great significance in the treatment of MDD. Transcranial direct cranial stimulation (tDCS) is a promising intervention for treating MDD, and it has demonstrated antidepressant effects and beneficial effects on cognitive function. The aim was to assess the efficacy of tDCS as a treatment for MDD. Four databases including PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), China National Knowledge Infrastructure (CNKI) and Wanfang database were searched for articles related to tDCS and major depression. The mean difference (MD) and 95% confidence interval (CI) were calculated in this study. A significant difference between tDCS compared with the control group in Montgomery-Asberg depression rating scale (MADRS) was found. There was a significant statistical difference between tDCS and the control group in Hamilton Depression Rating Scale, 17-items (HDRS-17). This study demonstrated that the intervention of active tDCS was superior to the use of sham tDCS in improving MDD. Furthermore, tDCS might be an effective treatment for MDD.

Repetitive transcranial magnetic stimulation significantly influences the eating behavior in depressive patients

BACKGROUND

Depressive syndrome is one of the most common of psychiatric diseases and is ranked as the largest single contributor to global disability. Depression worsens the treatment outcomes of comorbid conditions and is a predictor of an increased mortality rate. Frequent comorbidities accompanying depressive syndrome are eating disorders (ED). The novel brain stimulation technique termed repetitive transcranial magnetic stimulation (rTMS) has been developed as a clinical tool to treat depression. Simultaneously the effect of rTMS has been studied on ED.

PURPOSE

The aim of this study was to monitor the correlation between the improvement in depressive symptoms and changes in eating behavior after rTMS treatment, and potential possibility of the utilization of rTMS in the treatment of these frequent comorbid conditions.

METHODS

To map the change in eating behavior, this study follows the changes in answers 5 and 7 in the Zung Self-Rating Depression Scale. The patients were treated with high-frequency rTMS focused on the left dorsolateral prefrontal cortex.

RESULTS

We observed a significant change in both questions. At the same time, the change in both questions correlates with a variance in the overall depressive symptoms.

CONCLUSION

The rTMS treatment of depressive syndrome resulted in significant clinical improvements, including changes in eating behavior.

PsychotherapyPlus: augmentation of cognitive behavioral therapy (CBT) with prefrontal transcranial direct current stimulation (tDCS) in major depressive disorder-study design and methodology of a multicenter double-blind randomized placebo-controlled trial

Major Depressive Disorder (MDD) is one of the most prevalent psychiatric disorders worldwide. About 20-30% of patients do not respond to the standard psychopharmacological and/or psychotherapeutic interventions. Mounting evidence from neuroimaging studies in MDD patients reveal altered activation patterns in lateral prefrontal brain areas. Successful cognitive behavioral therapy (CBT) is associated with a recovery of these neural alterations. Moreover, it has been demonstrated that transcranial direct current stimulation (tDCS) is capable of influencing prefrontal cortex activity and cognitive functions such as working memory and emotion regulation. Thus, a clinical trial investigating the effects of an antidepressant intervention combining CBT with tDCS seems promising. The present study investigates the antidepressant efficacy of a combined CBT-tDCS intervention as compared to CBT with sham-tDCS or CBT alone. A total of 192 patients (age range 20-65 years) with MDD (Hamilton Depression Rating Scale Score ≥ 15, 21-item version) will be recruited at four study sites across Germany (Berlin, Munich, Tuebingen, and Freiburg) and randomly assigned to one of the following three treatment arms: (1) CBT + active tDCS; (2) CBT + sham-tDCS; and (3) CBT alone. All participants will attend a 6-week psychotherapeutic intervention comprising 12 sessions of CBT each lasting 100 min in a closed group setting. tDCS will be applied simultaneously with CBT. Active tDCS includes stimulation with an intensity of 2 mA for 30 min with the anode placed over F3 and the cathode over F4 according to the EEG 10-20 system, if assigned. The primary outcome measure is the change in Montgomery-Åsberg Depression Rating Scale scores from baseline to 6, 18, and 30 weeks after the first session. Participants also undergo pre- and post-treatment neuropsychological testing and functional magnetic resonance imaging (fMRI) to assess changes in prefrontal functioning and connectivity. The study investigates whether CBT can be augmented by non-invasive brain stimulation techniques such as tDCS in the treatment of MDD. It is designed as a proof-of-principle trial for the combined tDCS-CBT treatment, but also allows the investigation of the neurobiological underpinnings of the interaction between both interventions in MDD. Trial registration ClinicalTrials.gov Identifier NCT02633449.

Crossover design in transcranial direct current stimulation studies on motor learning: potential pitfalls and difficulties in interpretation of findings

Crossover designs are used by a high proportion of studies investigating the effects of transcranial direct current stimulation (tDCS) on motor learning. These designs necessitate attention to aspects of data collection and analysis to take account of design-related confounds including order, carryover, and period effects. In this systematic review, we appraised the method sections of crossover-designed tDCS studies of motor learning and discussed the strategies adopted to address these factors. A systematic search of 10 databases was performed and 19 research papers, including 21 experimental studies, were identified. Potential risks of bias were addressed in all of the studies, however, not in a rigorous and structured manner. In the data collection phase, unclear methods of randomization, various lengths of washout period, and inconsistency in the counteracting period effect can be observed. In the analytical procedures, the stratification by sequence group was often ignored, and data were treated as if it belongs to a simple repeated-measures design. An inappropriate use of crossover design can seriously affect the findings and therefore the conclusions drawn from tDCS studies on motor learning. The results indicate a pressing need for the development of detailed guidelines for this type of studies to benefit from the advantages of a crossover design.

Transcranial Direct Current Stimulation in the Acute Depressive Episode: A Systematic Review of Current Knowledge

Major depressive disorder is a severe, refractory mental disorder. Only one third of patients treated with antidepressants achieve remission after 3 trials, while subject to adverse effects. Therefore, the investigation of alternative treatments is paramount. The aim of this systematic review was to summarize the most recent evidence of transcranial direct current stimulation (tDCS) intervention for the acute phase of major depressive disorder. A PubMed search was performed including the terms "transcranial direct current stimulation" OR "transcranial direct stimulation" OR "tDCS" AND "major depressive disorder" OR "major depression" OR "depression" AND "trial." The search was conducted from inception until February 2018. Our search yielded initially 165 results, and 14 randomized clinical trials were included according to eligibility criteria. Most studies were pilot studies, with mixed findings. Two large randomized clinical trials recently published also presented primary negative findings. Study protocols usually used anodal left/cathodal right dorsolateral prefrontal cortex stimulation, 1 to 2.5 mA, and 5 to 20 tDCS sessions. We discuss the limitations of the included trials, such as sample and tDCS parameters heterogeneity between studies. To conclude, tDCS seems to be safe and devoid of serious adverse effects, although robust efficacy has not been consistently demonstrated in clinical trials assessing an acute treatment course of up to 4 weeks. Further directions are discussed, such as parameter individualization, investigation of biological markers, and home-use tDCS.

Effects of transcranial direct current stimulation on working memory and negative symptoms in schizophrenia: a phase II randomized sham-controlled trial

BACKGROUND

The lack of efficacy of pharmacological treatments for cognitive and negative symptoms in schizophrenia highlights the need for new interventions. We investigated the effects of tDCS on working memory and negative symptoms in patients with schizophrenia.

METHOD

Double-blinded, randomized, sham-controlled clinical trial, investigating the effects of 10 sessions of tDCS in schizophrenia subjects. Stimulation used 2 mA, for 20 min, with electrodes of 25 cm2 wrapped in cotton material soaked in saline solution. Anode was positioned over the left DLPFC and the cathode in the contralateral area. Twenty-four participants were assessed at baseline, after intervention and in a three-months follow-up. The primary outcome was the working memory score from MATRICS and the secondary outcome the negative score from PANSS. Data were analyzed using generalized estimating equations.

RESULTS

We did not find group ∗ time interaction for the working memory (p = 0.720) score or any other cognitive variable (p > 0.05). We found a significant group ∗ time interaction for PANSS negative (p < 0.001, d = 0.23, CI.95 = -0.59-1.02), general (p = 0.011) and total scores (p < 0.001). Exploratory analysis of PANSS 5 factors suggests tDCS effect on PANSS negative (p = 0.012), cognitive (p = 0.016) and depression factors (p = 0.029).

CONCLUSION

The results from this trial highlight the therapeutic effects of tDCS for treatment of persistent symptoms in schizophrenia, with reduction of negative symptoms. We were not able to confirm the superiority of active tDCS over sham to improve working memory performance. Larger sample size studies are needed to confirm these findings.

Rigor and reproducibility in research with transcranial electrical stimulation: An NIMH-sponsored workshop

BACKGROUND

Neuropsychiatric disorders are a leading source of disability and require novel treatments that target mechanisms of disease. As such disorders are thought to result from aberrant neuronal circuit activity, neuromodulation approaches are of increasing interest given their potential for manipulating circuits directly. Low intensity transcranial electrical stimulation (tES) with direct currents (transcranial direct current stimulation, tDCS) or alternating currents (transcranial alternating current stimulation, tACS) represent novel, safe, well-tolerated, and relatively inexpensive putative treatment modalities.

OBJECTIVE

This report seeks to promote the science, technology and effective clinical applications of these modalities, identify research challenges, and suggest approaches for addressing these needs in order to achieve rigorous, reproducible findings that can advance clinical treatment.

METHODS

The National Institute of Mental Health (NIMH) convened a workshop in September 2016 that brought together experts in basic and human neuroscience, electrical stimulation biophysics and devices, and clinical trial methods to examine the physiological mechanisms underlying tDCS/tACS, technologies and technical strategies for optimizing stimulation protocols, and the state of the science with respect to therapeutic applications and trial designs.

RESULTS

Advances in understanding mechanisms, methodological and technological improvements (e.g., electronics, computational models to facilitate proper dosing), and improved clinical trial designs are poised to advance rigorous, reproducible therapeutic applications of these techniques. A number of challenges were identified and meeting participants made recommendations made to address them.

CONCLUSIONS

These recommendations align with requirements in NIMH funding opportunity announcements to, among other needs, define dosimetry, demonstrate dose/response relationships, implement rigorous blinded trial designs, employ computational modeling, and demonstrate target engagement when testing stimulation-based interventions for the treatment of mental disorders.

A systematic review and meta-analysis on placebo response to repetitive transcranial magnetic stimulation for depression trials

BACKGROUND

Although several studies indicate that placebo response is large to antidepressant pharmacotherapy in major depressive disorder (MDD), no updated meta-analysis has quantified the magnitude of the placebo (sham) response to repetitive transcranial magnetic stimulation (rTMS) in MDD yet.

OBJECTIVE

To conduct a systematic review and meta-analysis on this issue in randomized controlled trials (RCTs) involving participants with MDD; and to explore potential moderators.

METHODOLOGY

PubMed/MEDLINE, Embase, PsycINFO, and Web of Science electronic databases were searched from inception up to March 15, 2017 for RCTs that investigated the efficacy of any rTMS modality compared to sham intervention in participants with acute depressive episodes. Cochrane Risk of Bias Tool was used to estimate risks. We estimated the placebo effect size (Hedges's g, random-effects model) response using placebo groups baseline and endpoint depressive symptom scores. Meta-regressions have been employed to explore potential moderators of response.

RESULTS

Sixty-one studies met eligibility criteria (N=1328; mean age, 47years; 57% females). Placebo response was large (g=0.8, 95% CI=0.65-0.95, p<0.01) regardless of the modality of intervention. Placebo response was directly associated with publication year and depression improvement of the active group, and inversely associated with higher levels of treatment-resistant depression. Other moderators, including gender, age, and stimulator type, were not associated with the outcome. Overall, 24.6%, 67.2%, and 8.2% of studies had an overall low, unclear, and high bias risk, respectively.

CONCLUSION

Placebo response in rTMS depression trials was large and associated with depression improvement of the active treatment group. Such result suggests that excluding placebo responders with a run-in phase may not confer advantage since response to 'active' rTMS may decrease as well. Moreover, placebo response may be a component of therapeutic response to rTMS in MDD. In addition, placebo response increase over time could indicate improvement in rTMS trial designs, including better sham rTMS methods.

Anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex modulates attention and pain in fibromyalgia: randomized clinical trial

Cognitive dysfunction in fibromyalgia patients has been reported, especially when increased attentional demands are required. Transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) has been effective in modulating attention. We tested the effects of a single session of tDCS coupled with a Go/No-go task in modulating three distinct attentional networks: alertness, orienting and executive control. Secondarily, the effect on pain measures was evaluated. Forty females with fibromyalgia were randomized to receive active or sham tDCS. Anodal stimulation (1 mA, 20 min) was applied over the DLPFC. Attention indices were assessed using the Attention Network Test (ANT). Heat pain threshold (HPTh) and tolerance (HPTo) were measured. Active compared to sham tDCS led to increased performance in the orienting (mean difference [MD] = 14.63) and executive (MD = 21.00) attention networks. There was no effect on alertness. Active tDCS increased HPTh as compared to sham (MD = 1.93) and HPTo (MD = 1.52). Regression analysis showed the effect on executive attention is mostly independent of the effect on pain. DLPFC may be an important target for neurostimulation therapies in addition to the primary motor cortex for patients who do not respond adequately to neurostimulation therapies.

Freezing of gait in Parkinson's disease: from pathophysiology to emerging therapies

Freezing of gait (FOG) is 'an episodic inability to generate effective stepping in the absence of any known cause other than parkinsonism or high level gait disorders'. FOG is one of the most disabling symptoms in Parkinson's disease, especially in its more advanced stages. Early recognition is important as FOG is related to higher fall risk and poorer prognosis. Although specific treatments are still elusive, there have been recent advances in the development of new therapeutic approaches. The aim of this review is to present the latest knowledge regarding the phenomenology, pathogenesis, diagnostic assessment and conventional treatment of FOG in Parkinson's disease. A review of the evidence supporting noninvasive brain stimulation will follow to highlight the potential of these strategies.

A Randomised Controlled Trial of Neuronavigated Repetitive Transcranial Magnetic Stimulation (rTMS) in Anorexia Nervosa

Background

Anorexia nervosa (AN) is associated with morbid fear of fatness, extreme food restriction and altered self-regulation. Neuroimaging data implicate fronto-striatal circuitry, including the dorsolateral prefrontal cortex (DLPFC).

Methods

In this double-blind parallel group study, we investigated the effects of one session of sham-controlled high-frequency repetitive transcranial magnetic stimulation (rTMS) to the left DLPFC (l-DLPFC) in 60 individuals with AN. A food exposure task was administered before and after the procedure to elicit AN-related symptoms.

Outcomes

The primary outcome measure was ‘core AN symptoms’, a variable which combined several subjective AN-related experiences. The effects of rTMS on other measures of psychopathology (e.g. mood), temporal discounting (TD; intertemporal choice behaviour) and on salivary cortisol concentrations were also investigated. Safety, tolerability and acceptability were assessed.

Results

Fourty-nine participants completed the study. Whilst there were no interaction effects of rTMS on core AN symptoms, there was a trend for group differences (p = 0.056): after controlling for pre-rTMS scores, individuals who received real rTMS had reduced symptoms post-rTMS and at 24-hour follow-up, relative to those who received sham stimulation. Other psychopathology was not altered differentially following real/sham rTMS. In relation to TD, there was an interaction trend (p = 0.060): real versus sham rTMS resulted in reduced rates of TD (more reflective choice behaviour). Salivary cortisol concentrations were unchanged by stimulation. rTMS was safe, well–tolerated and was considered an acceptable intervention.

Conclusions

This study provides modest evidence that rTMS to the l-DLPFC transiently reduces core symptoms of AN and encourages prudent decision making. Importantly, individuals with AN considered rTMS to be a viable treatment option. These findings require replication in multiple-session studies to evaluate therapeutic efficacy.

Trial Registration

www.Controlled-Trials.comISRCTN22851337

A systematic review of the clinical efficacy of transcranial direct current stimulation (tDCS) in psychiatric disorders

Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique, which can be used to selectively disrupt patterns of neural activity that are associated with symptoms of mental illness. tDCS has been implemented in numerous therapeutic trials across a range of patient populations, with a rapidly increasing number of studies being published each year. This systematic review aimed to evaluate the efficacy of tDCS in the treatment of psychiatric disorders. Four electronic databases were searched from inception until December 2015 by two independent reviewers, and 66 eligible studies were identified. Depression was the most extensively researched condition, followed by schizophrenia and substance use disorders. Data on obsessive compulsive disorder, generalised anxiety disorder, and anorexia nervosa were also obtained. The quality of included studies was appraised using a standardised assessment framework, which yielded a median score corresponding to "weak" on the three-point scale. This improved to "moderate" when case reports/series were excluded from the analysis. Overall, data suggested that tDCS interventions comprising multiple sessions can ameliorate symptoms of several major psychiatric disorders, both acutely and in the long-term. Nevertheless, the tDCS field is still in its infancy, and several methodological and ethical issues must be addressed before clinical efficacy can truly be determined. Studies probing the mechanisms of action of tDCS and those facilitating the definition of optimised stimulation protocols are warranted. Furthermore, evidence from large-scale, multi-centre randomised controlled trials is required if the transition of this therapy from the laboratory to the clinic is to be considered.

Changes in resting state functional connectivity after repetitive transcranial direct current stimulation applied to motor cortex in fibromyalgia patients

BACKGROUND

Fibromyalgia (FM) is a chronic, centralized pain condition characterized by alterations in the functional, chemical, and structural brain networks responsible for sensory and mood processing. Transcranial direct current stimulation (tDCS) has emerged as a potential treatment for FM. tDCS can alter functional connectivity (FC) in brain regions underneath and distant to the stimulating electrode, although the analgesic mechanisms of repetitive tDCS remain unknown. The aim of this study was to investigate how a clinically relevant schedule of tDCS sessions alters resting state FC and how these changes might relate to clinical pain.

METHODS

Resting state functional magnetic resonance imaging data were collected from 12 patients with FM at baseline, after 5 days of sham treatment, and after 5 days of real tDCS with the anode over the left primary motor cortex (M1) and the cathode over the right supraorbital cortex. Seed to whole-brain FC analyses were performed with seed regions placed in bilateral M1, primary somatosensory cortices (S1), ventral lateral (VL) and ventral posterolateral (VPL) thalami, and periaqueductal gray (PAG).

RESULTS

Stronger baseline FC between M1-VL thalamus, S1-anterior insula, and VL thalamus-PAG predicted greater analgesia after sham and real tDCS. Sham treatment (compared with baseline) reduced FC between the VPL thalamus, S1, and the amygdala. Real tDCS (compared with sham treatment) reduced FC between the VL thalamus, medial prefrontal, and supplementary motor cortices. Interestingly, decreased FC between the VL/VPL thalamus and posterior insula, M1, and S1 correlated with reductions in clinical pain after both sham and active treatments.

CONCLUSIONS

These results suggest that while there may be a placebo response common to both sham and real tDCS, repetitive M1 tDCS causes distinct changes in FC that last beyond the stimulation period and may produce analgesia by altering thalamic connectivity.

Clinical outcomes and neural correlates of 20 sessions of repetitive transcranial magnetic stimulation in severe and enduring anorexia nervosa (the TIARA study): study protocol for a randomised controlled feasibility trial

BACKGROUND

Anorexia nervosa (AN) is a serious mental disorder with multiple comorbidities and complications. In those with a severe and enduring form of the illness (SEED-AN), treatment responsivity is poor and the evidence base limited. Thus, there is a need for novel treatment strategies. This paper describes the theoretical background and protocol of a feasibility randomised controlled trial (RCT) of real versus sham (placebo) therapeutic repetitive transcranial magnetic stimulation (rTMS) in SEED-AN. The aim of this trial is to obtain information that will guide decision making and protocol development in relation to a future large-scale RCT of rTMS in this group of patients, and also to assess the preliminary efficacy and neural correlates of rTMS treatment.

DESIGN

Forty-four adults from the community with a DSM-5 diagnosis of AN, an illness duration>3 years and a previous course of unsuccessful treatment will be randomly allocated to receive 20 sessions of either real or sham rTMS, in a parallel group design. As this is a feasibility study, no primary outcome has been defined and a broad range of outcome variables will be examined. These include weight/body mass index (BMI), eating disorder psychopathology, other psychopathology (for example, depression, anxiety), quality of life, neuropsychological processes (such as self-regulation, attentional bias and food choice behaviour), neuroimaging measures (that is, changes in brain structure or function), tolerability and acceptability of rTMS, and additional service utilisation. The feasibility of conducting a large-scale RCT of rTMS and the appropriateness of rTMS as a treatment for SEED-AN will be evaluated through: assessment of recruitment and retention rates, acceptability of random allocation, blinding success (allocation concealment), completion of treatment sessions and research assessments (baseline, post-treatment and follow-up assessments). The acceptability and tolerability of the treatment will be assessed via semi-structured interviews.

DISCUSSION

The effect sizes generated and other findings from this trial will inform a future large-scale RCT with respect to decisions on primary outcome measures and other aspects of protocol development. Additionally, results from this study will provide a preliminary indication of the efficacy of rTMS treatment for AN, the neural correlates of the illness, and potential biomarkers of clinical response.

TRIAL REGISTRATION

ISRCTN14329415 . Date of registration: 23 July 2015.

Transcranial magnetic stimulation in autism spectrum disorder: Challenges, promise, and roadmap for future research

Autism Spectrum Disorder (ASD) is a behaviorally defined complex neurodevelopmental syndrome characterized by impairments in social communication, by the presence of restricted and repetitive behaviors, interests and activities, and by abnormalities in sensory reactivity. Transcranial magnetic stimulation (TMS) is a promising, emerging tool for the study and potential treatment of ASD. Recent studies suggest that TMS measures provide rapid and noninvasive pathophysiological ASD biomarkers. Furthermore, repetitive TMS (rTMS) may represent a novel treatment strategy for reducing some of the core and associated ASD symptoms. However, the available literature on the TMS use in ASD is preliminary, composed of studies with methodological limitations. Thus, off-label clinical rTMS use for therapeutic interventions in ASD without an investigational device exemption and outside of an IRB approved research trial is premature pending further, adequately powered and controlled trials. Leaders in this field have gathered annually for a two-day conference (prior to the 2014 and 2015 International Meeting for Autism Research, IMFAR) to share recent progress, promote collaboration across laboratories, and establish consensus on protocols. Here we review the literature in the use of TMS in ASD in the context of the unique challenges required for the study and exploration of treatment strategies in this population. We also suggest future directions for this field of investigations. While its true potential in ASD has yet to be delineated, TMS represents an innovative research tool and a novel, possibly transformative approach to the treatment of neurodevelopmental disorders.

Neural correlates of clinical improvement after deep transcranial magnetic stimulation (DTMS) for treatment-resistant depression: a case report using functional magnetic resonance imaging

We report the effects of a 4-week trial of deep transcranial magnetic stimulation (DTMS) on depressive and anxious symptoms and brain activity in a patient (Mrs A) with treatment-resistant depression (TRD). The protocol involved a pre- and a post-functional magnetic resonance imaging (fMRI) scan during which Mrs A had to perform a working memory task (i.e., n-back). Her baseline score on the 21-item Hamilton Depression Rating Scale (HAM-D21) was 24, indicating severe depressive symptoms. Immediately after 4 weeks of daily DTMS treatment applied over the left dorsolateral prefrontal cortex (DLPFC), her HAM-D21 score decreased to 13 (a 46% reduction), and 1 month later, it was 12 (a 50% reduction). Moreover, Mrs A's accuracy scores on the n-back task (i.e., 2-back condition) improved from 79% (baseline) to 96% (after DTMS treatment). At the neural level, Mrs A showed significantly increased brain activity in the working memory network (e.g., DLPFC, parietal cortex) during the execution of the 2-back condition after DTMS treatment compared to baseline.

Bilateral repetitive transcranial magnetic stimulation for treatment-resistant depression: a systematic review and meta-analysis of randomized controlled trials

There has been concern regarding the use of controversial paradigms for repetitive transcranial magnetic stimulation (rTMS) to manage treatment-resistant depression (TRD). This meta-analysis assessed the efficacy of bilateral rTMS compared with unilateral and sham rTMS in patients with TRD. PubMed, Embase, CENTRAL, PsycINFO, Web of Science, EAGLE and NTIS databases were searched to identify relevant studies, and randomized controlled trials (RCTs) on bilateral rTMS for TRD patients were included. The response was defined as the primary outcome, and remission was the secondary outcome. Ten RCTs that included 634 patients met the eligibility criteria. The risk ratio (RRs) of both the primary and secondary outcomes of bilateral rTMS showed non-significant increases compared to unilateral rTMS (RR=1.01, P=0.93; odds ratio [OR]=0.77, P=0.22). Notably, the RR of the primary bilateral rTMS outcome was significantly increased compared to that for sham rTMS (RR=3.43, P=0.0004). The results of our analysis demonstrated that bilateral rTMS was significantly more effective than sham rTMS but not unilateral rTMS in patients with TRD. Thus, bilateral rTMS may not be a useful paradigm for patients with TRD.

Augmenting antidepressants with deep transcranial magnetic stimulation (DTMS) in treatment-resistant major depression

OBJECTIVES

Deep transcranial magnetic stimulation (DTMS) has been shown to be efficacious and relatively safe for major depressive disorder (MDD). However, its clinical utility as an augmenting strategy for treatment-resistant depression (TRD) remains unexplored.

METHODS

In an open label trial, 17 outpatients with severe TRD received 4 weeks of daily high frequency DTMS over the left dorsolateral prefrontal cortex. Depressive and anxious symptoms, suicidality and quality of life (QOL) were measured at baseline (i.e., in the week prior to the start of the DTMS treatment) and at week 5 (i.e., in the week following the end of the DTMS treatment). Primary outcome measures were rates of response and remission at week 5 using an intention-to-treat approach.

RESULTS

Response and remission rates at week 5 were 70.6 and 41.2%, respectively. Also, depression, anxiety, and suicidality ratings were significantly improved by week 5 (with Hedges' g estimates ranging from 0.6 to 1.72), as well as four of the five QOL domain scores (i.e., global, psychological, environmental and social). Finally, two patients dropped out of the study at week 1 because of significant scalp discomfort during stimulation.

CONCLUSIONS

Our study suggests that DTMS, when used as an augmenting strategy for antidepressants in severe TRD, is efficacious, safe and relatively well tolerated. However, controlled studies with larger samples are needed to confirm and expand our preliminary findings.

Impact of two or less missing treatment sessions on tDCS clinical efficacy: results from a factorial, randomized, controlled trial in major depression

OBJECTIVES

Transcranial direct current stimulation (tDCS) is a neuromodulatory intervention with recent clinical trials showing promising results in major depression treatment. Although tDCS has some appealing characteristics (e.g., low cost, ease of use, and relatively benign profile of adverse effects), one important drawback of the technique is the need to deliver consecutive, repeated sessions for several weekdays. However, no study investigated whether absences during this acute treatment phase impact on tDCS efficacy, and, if so, whether absences should be considered dropouts, therefore increasing attrition.

MATERIAL AND METHODS

To examine this issue, we used data from a randomized, factorial, sham-controlled tDCS study that recruited 120 depressed patients. In this trial, the acute treatment phase consisted of ten consecutive sessions delivered once daily from Monday to Friday; two nonconsecutive missed visits were allowed, with extra tDCS sessions being performed to complete the original number of sessions.

RESULTS

Our main finding was that the procedure of granting one to two absences during the acute treatment phase did not impact on tDCS antidepressant efficacy. Moreover, out of 103 completers, only 41 (39.8%) patients presented no missing visits and 25 (24.3%) presented two absences. These patients did not differ in clinical and demographic characteristics; thus, absences were probably circumstantial (e.g., traffic congestion, personal obligations).

CONCLUSIONS

Absences during the acute tDCS treatment phase are common, which support the use of flexible schedules in future tDCS trials as to minimize attrition. Also, further studies should access whether higher number of absences can compromise optimal tDCS efficacy.

Therapeutic time window of noninvasive brain stimulation for pain treatment: inhibition of maladaptive plasticity with early intervention

Neuromodulatory effects of noninvasive brain stimulation (NIBS) have been extensively studied in chronic disorders such as major depression, chronic pain and stroke. However, few studies have explored the use of these techniques in acute conditions. A possible use of NIBS in acute disorders is to prevent or reverse ongoing maladaptive plastic alterations, seemingly responsible for treatment refractoriness and detrimental behavioral changes. In this review, the authors discuss the potential role of NIBS in blocking maladaptive plasticity using the transition of acute to chronic pain in conditions such as postsurgical pain, central poststroke pain, pain after spinal cord injury and pain after traumatic brain injury as a model. The authors also present suggestions for clinical trial design using NIBS in the acute stage of illnesses.

Differential improvement in depressive symptoms for tDCS alone and combined with pharmacotherapy: an exploratory analysis from the Sertraline vs. Electrical Current Therapy for Treating Depression Clinical Study

Transcranial direct current stimulation (tDCS) is a promising therapy for major depression treatment, although little is known of its effects in ameliorating distinct symptoms of depression. Thus, it is important, not only to increase knowledge of its antidepressant mechanisms, but also to guide its potential use in clinical practice. Using data from a recent factorial, double-blinded, placebo-controlled trial applying tDCS-alone and combined with sertraline to treat 120 depressed outpatients over 6 wk (Brunoni et al., 2013), we investigated the pattern of improvement in symptoms of depression from the Montgomery-Asberg depression scale (MADRS). First, we performed one multivariate analysis of variance with the score improvement of the 10 MADRS items as dependent variables. Significant (p < 0.05) results were further explored with follow-up analyses of variance. TDCS (alone and combined with sertraline) improved concentration difficulties and pessimistic and suicidal thoughts. The combined treatment also improved apparent and reported sadness, lassitude and inability to feel. Indeed, tDCS/sertraline significantly ameliorated all but the 'vegetative' depression symptoms (inner tension, sleep and appetite items). We further discuss whether bifrontal tDCS over the dorsolateral prefrontal cortex could be associated with improvement in cognitive (concentration) and affective (pessimistic/suicidal thoughts) processing, while the combined treatment might have a more widespread antidepressant effect by simultaneously acting on different depression pathways. We also identified patterns of antidepressant improvement for tDCS that might aid in tailoring specific interventions for different subtypes of depressed patients, e.g. particularly those with suicidal ideation.

rTMS for pharmacoresistant major depression in the clinical setting of a psychiatric hospital: effectiveness and effects of age

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method of brain stimulation used in the treatment of drug-resistant major depressive disorder (MDD). It has been suggested that the efficacy of rTMS decreases with the age of the patient, but the data are contradictory. Here, we analyze in our clinical setting the efficacy of a 3-week rTMS treatment in drug-resistant MDD during a 3 month period and the potential influence of age on this efficacy.

METHODS

Stimulation consisted of 15 sessions of rTMS over the dorsolateral prefrontal cortex. Clinical evaluations included the Hamilton Depression Rating Scale (HDRS), and the Beck Depression Inventory (BDI) at baseline, after 3 weeks of treatment, and 1 month and 3 months after the last session.

RESULTS

Data from 93 patients issued from the 178 patients active file were analyzed. The antidepressant effect observed in the two age groups (<65 and ≥65) did not differ at the end of the treatment and 3 months later, with a comparable number of responders (50% decrease in HDRS score from baseline) (53.3% for age <65 versus 46.7% for age ≥65, p=0.51). The treatment had a significant effect over time. We found no evidence of the age affecting outcome at 3 months after the last session.

LIMITATIONS

Previous antidepressant treatments, and therapeutic drug use modifications after rTMS treatment, degree of pharmaco-resistance or duration of current episode are not reported.

CONCLUSION

RTMS of the DFPLC is effective as an add-on treatment for cases of pharmacologically refractory major depression, independent of the patient age.

Comparison of blinding effectiveness between sham tDCS and placebo sertraline in a 6-week major depression randomized clinical trial

OBJECTIVE

To compare blinding integrity and associated factors for transcranial direct current stimulation (tDCS) vs. placebo-pill, the gold standard blinding method.

METHODS

Parallel trial. Depressed participants were randomized to verum/placebo sertraline and active/sham tDCS (2mA, 30-min 10-daily sessions and two additional, fortnight sessions) over 6weeks. Blinding was assessed in completers (n=102) and in a random subgroup (n=35) of raters and participants, in which we also inquired to qualitatively describe their strongest guessing reason.

RESULTS

Participants and raters presented similar performance for predicting treatment assignment at endpoint, correctly guessing tDCS and sertraline beyond chance. Nevertheless, clinical response was associated with correct prediction and tDCS non-responders failed to predict the allocation group. For tDCS, "trouble concentrating" was inversely associated with correct prediction. "Skin redness" was more reported for active-tDCS, but did not predict the allocation group. The qualitative reasons for raters' guessing were not associated with correct prediction, whereas for participants clinical response and adverse effects were directly and inversely associated with correct prediction, respectively.

CONCLUSION

Blinding integrity of tDCS and sertraline were comparable and mainly associated with efficacy rather than blinding failure.

SIGNIFICANCE

TDCS blinding can be improved by adopting parallel designs and avoiding subjects' awareness of skin redness.

Blinding integrity in randomized sham-controlled trials of repetitive transcranial magnetic stimulation for major depression: a systematic review and meta-analysis

Repetitive transcranial magnetic stimulation (rTMS) is a safe and effective treatment for major depression (MD). However, the perceived lack of a suitable sham rTMS condition might have compromised the success of blinding procedures in clinical trials. Thus, we conducted a systematic review and meta-analysis of randomized, double-blind and sham-controlled trials (RCTs) on high frequency (HF-), low frequency (LF-) and bilateral rTMS for MD. We searched the literature from January 1995 to July 2012 using Medline, EMBASE, PsycINFO, Cochrane Central Register of Controlled Trials and Scopus. The main outcome measure was participants' ability to correctly guess their treatment allocation at study end. We used a random-effects model and risk difference (RD). Overall, data were obtained from seven and two RCTs on HF- and bilateral rTMS, respectively. No RCT on LF-rTMS reporting on blinding success was found. HF- and bilateral rTMS trials enrolled 396 and 93 depressed subjects and offered an average of approximately 13 sessions. At study end, 52 and 59% of subjects receiving HF-rTMS and sham rTMS were able to correctly guess their treatment allocation, a non-significant difference (RD = -0.04; z = -0.51; p = 0.61). Furthermore, 63.3 and 57.5% of subjects receiving bilateral and sham rTMS were able to correctly guess their treatment allocation, also a non-significant difference (RD = 0.05; z = 0.49; p = 0.62). In addition, the use of angulation and sham coil in HF-rTMS trials produced similar results. In summary, existing sham rTMS interventions appear to result in acceptable levels of blinding regarding treatment allocation.

Evaluation of sham transcranial direct current stimulation for randomized, placebo-controlled clinical trials

BACKGROUND

Transcranial direct current stimulation (tDCS) has been investigated as therapeutic intervention in various psychiatric and neurologic disorders. As placebo responses to technical interventions may be pronounced in many clinical conditions, it is important to thoroughly develop placebo conditions which meet the requirements for application in randomized double-blind controlled trials.

OBJECTIVE

The two-part experiment reported here aims at evaluating a new sham tDCS condition in healthy subjects and device operators. Sham or active tDCS is delivered after entering a number code to the device and allows blinding of the operator before and during tDCS. The sham mode has no short stimulation period.

METHODS

The experimental sequence was as follows: 1) Evaluation of successful blinding by comparing placebo to active stimulation at prefrontal sites based on the rating of subjects undergoing tDCS, 2) Evaluation of successful blinding by comparing placebo to active stimulation at prefrontal sites based on the operator/observer ratings.

RESULTS

Subjects were not able to distinguish between active and sham tDCS for prefrontal stimulation. Overall there was no relevant discomfort and tDCS was well tolerated. Operators/observers were able to identify sham stimulation based on skin reddening after active, but not after sham tDCS.

CONCLUSIONS

The tDCS sham condition investigated here may be suitable for placebo-controlled trials keeping subjects blind to treatment conditions. However, operators can easily be aware of the condition applied and they should not get involved in rating outcome measures during the course of high standard placebo-controlled trials.

Feasibility of focal transcranial DC polarization with simultaneous EEG recording: preliminary assessment in healthy subjects and human epilepsy

We aimed to investigate the feasibility of an experimental system for simultaneous transcranial DC stimulation (tDCS) and EEG recording in human epilepsy. We report tolerability of this system in a cross-over controlled trial with 15 healthy subjects and preliminary effects of its use, testing repeated tDCS sessions, in two patients with drug-refractory Continuous Spike-Wave Discharges During Slow Sleep (CSWS). Our system combining continuous recording of the EEG with tDCS allows detailed evaluation of the interictal activity during the entire process. Stimulation with 1 mA was well-tolerated in both healthy volunteers and patients with refractory epilepsy. The large reduction in interictal epileptiform EEG discharges in the two subjects with epilepsy supports further investigation of tDCS using this combined method of stimulation and monitoring in epilepsy. Continuous monitoring of epileptic activity throughout tDCS improves safety and allows detailed evaluation of epileptic activity changes induced by tDCS in patients.

Cranial electrotherapy stimulation and transcranial pulsed current stimulation: a computer based high-resolution modeling study

The field of non-invasive brain stimulation has developed significantly over the last two decades. Though two techniques of noninvasive brain stimulation--transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS)--are becoming established tools for research in neuroscience and for some clinical applications, related techniques that also show some promising clinical results have not been developed at the same pace. One of these related techniques is cranial electrotherapy stimulation (CES), a class of transcranial pulsed current stimulation (tPCS). In order to understand further the mechanisms of CES, we aimed to model CES using a magnetic resonance imaging (MRI)-derived finite element head model including cortical and also subcortical structures. Cortical electric field (current density) peak intensities and distributions were analyzed. We evaluated different electrode configurations of CES including in-ear and over-ear montages. Our results confirm that significant amounts of current pass the skull and reach cortical and subcortical structures. In addition, depending on the montage, induced currents at subcortical areas, such as midbrain, pons, thalamus and hypothalamus are of similar magnitude than that of cortical areas. Incremental variations of electrode position on the head surface also influence which cortical regions are modulated. The high-resolution modeling predictions suggest that details of electrode montage influence current flow through superficial and deep structures. Finally we present laptop based methods for tPCS dose design using dominant frequency and spherical models. These modeling predictions and tools are the first step to advance rational and optimized use of tPCS and CES.

Somatic therapies for treatment-resistant depression: ECT, TMS, VNS, DBS

The field of non-pharmacological therapies for treatment resistant depression (TRD) is rapidly evolving and new somatic therapies are valuable options for patients who have failed numerous other treatments. A major challenge for clinicians (and patients alike) is how to integrate the results from published clinical trials in the clinical decision-making process.

We reviewed the literature for articles reporting results for clinical trials in particular efficacy data, contraindications and side effects of somatic therapies including electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS), vagal nerve stimulation (VNS) and deep brain stimulation (DBS). Each of these devices has an indication for patients with different level of treatment resistance, based on acuteness of illness, likelihood of response, costs and associated risks. ECT is widely available and its effects are relatively rapid in severe TRD, but its cognitive adverse effects may be cumbersome. TMS is safe and well tolerated, and it has been approved by FDA for adults who have failed to respond to one antidepressant, but its use in TRD is still controversial as it is not supported by rigorous double-blind randomized clinical trials. The options requiring surgical approach are VNS and DBS. VNS has been FDA-approved for TRD, however it is not indicated for management of acute illness. DBS for TRD is still an experimental area of investigation and double-blind clinical trials are underway.

Clinical research with transcranial direct current stimulation (tDCS): challenges and future directions

BACKGROUND

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low-intensity, direct current to cortical areas facilitating or inhibiting spontaneous neuronal activity. In the past 10 years, tDCS physiologic mechanisms of action have been intensively investigated giving support for the investigation of its applications in clinical neuropsychiatry and rehabilitation. However, new methodologic, ethical, and regulatory issues emerge when translating the findings of preclinical and phase I studies into phase II and III clinical studies. The aim of this comprehensive review is to discuss the key challenges of this process and possible methods to address them.

METHODS

We convened a workgroup of researchers in the field to review, discuss, and provide updates and key challenges of tDCS use in clinical research.

MAIN FINDINGS/DISCUSSION

We reviewed several basic and clinical studies in the field and identified potential limitations, taking into account the particularities of the technique. We review and discuss the findings into four topics: (1) mechanisms of action of tDCS, parameters of use and computer-based human brain modeling investigating electric current fields and magnitude induced by tDCS; (2) methodologic aspects related to the clinical research of tDCS as divided according to study phase (ie, preclinical, phase I, phase II, and phase III studies); (3) ethical and regulatory concerns; and (4) future directions regarding novel approaches, novel devices, and future studies involving tDCS. Finally, we propose some alternative methods to facilitate clinical research on tDCS.

tDCS-induced analgesia and electrical fields in pain-related neural networks in chronic migraine

OBJECTIVE

We investigated in a sham-controlled trial the analgesic effects of a 4-week treatment of transcranial direct current stimulation (tDCS) over the primary motor cortex in chronic migraine. In addition, using a high-resolution tDCS computational model, we analyzed the current flow (electric field) through brain regions associated with pain perception and modulation.

METHODS

Thirteen patients with chronic migraine were randomized to receive 10 sessions of active or sham tDCS for 20 minutes with 2 mA over 4 weeks. Data were collected during baseline, treatment and follow-up. For the tDCS computational analysis, we adapted a high-resolution individualized model incorporating accurate segmentation of cortical and subcortical structures of interest.

RESULTS

There was a significant interaction term (time vs group) for the main outcome (pain intensity) and for the length of migraine episodes (ANOVA, P < .05 for both analyses). Post-hoc analysis showed a significant improvement in the follow-up period for the active tDCS group only. Our computational modeling studies predicted electric current flow in multiple cortical and subcortical regions associated with migraine pathophysiology. Significant electric fields were generated, not only in targeted cortical regions but also in the insula, cingulate cortex, thalamus, and brainstem regions.

CONCLUSIONS

Our findings give preliminary evidence that patients with chronic migraine have a positive, but delayed, response to anodal tDCS of the primary motor cortex. These effects may be related to electrical currents induced in pain-related cortical and subcortical regions.

Pharmacological and combined interventions for the acute depressive episode: focus on efficacy and tolerability

BACKGROUND

Use of antidepressants is the gold standard therapy for major depression. However, despite the large number of commercially available antidepressant drugs there are several differences among them in efficacy, tolerability, and cost-effectiveness. In addition the optimal augmentation strategy is still not clear when dealing with treatment-resistant depression, a condition that affects 15% to 40% of depressed patients.

METHODS

We therefore reviewed the main characteristics of these drugs regarding their efficacy, tolerability, side effects and cost-effectiveness, by accessing all meta-analyses and systematic reviews published from 2004 to 2009. In addition, we reviewed the augmentation strategy of associated antidepressants with neurostimulation therapies (such as transcranial magnetic stimulation [TMS] and transcranial direct current stimulation [tDCS]). A search was undertaken in MEDLINE, Web of Science, Cochrane, and Scielo databases. We included: 21 meta-analyses of antidepressant trials, 15 neurostimulation clinical trials and 8 studies of pharmacoeconomics. We then performed a comprehensive review on these articles.

RESULTS AND CONCLUSION

Although recent meta-analyses suggest sertraline and escitalopram might have increased efficacy/tolerability, other studies and large pragmatic trials have not found these to be superior to other antidepressant drugs. Also, we did not identify any superior drug in terms of cost-effectiveness due to the different designs observed among pharmacoecomics studies. Side effects such as sexual dysfunction, gastrointestinal problems and weight gain were common causes of discontinuation. Tolerability was an important issue for novel neurostimulation interventions, such as TMS and tDCS. These therapies might be interesting augmentation strategies, considering their benign profile of side effects, if proper safety parameters are adopted.