Transcranial direct current stimulation for the treatment of generalized anxiety disorder: A randomized clinical trial

Evaluating the efficacy and acceptability of non-invasive brain stimulation for generalized anxiety disorder: a systematic review and network meta-analysis

Non-invasive brain stimulation (NIBS) has the potential to treat generalized anxiety disorder (GAD). To assess the efficacy (response/remission/post-treatment continuous anxiety severity scores) and acceptability (failure to complete treatment for any reason) of NIBS, we searched PubMed, Web of Science, and the Cochrane Library (as of April 2024) for articles on NIBS for GAD and conducted a network meta-analysis of eight randomized trials (20 treatment arms, 405 participants). Data were pooled using standardized mean difference (SMD) and odds ratio (OR) with 95 % confidence interval (CI). Repetitive transcranial magnetic stimulation (rTMS) was the most widely studied treatment for GAD. The right dorsolateral prefrontal cortex (DLPFC) was the most common treatment target for GAD. High-frequency rTMS showed higher response rates (OR 291.40, 95 % CI 13.08 to 6490.21) and remission rates (OR 182.14, 95 % CI 8.72 to 3805.76) compared with other active therapies. Continuous theta burst stimulation (cTBS) greatly improved continuous post-treatment anxiety severity scores (SMD -2.56, 95 % CI -3.16 to -1.96). No significant differences in acceptability were found between the treatment strategies and the sham stimulation group. These findings provide evidence to consider NIBS techniques as alternative or adjunctive treatments for GAD.

Impact of Electrical Stimulation on Mental Stress, Depression, and Anxiety: A Systematic Review

Individuals experiencing high levels of stress face significant impacts on their overall well-being and quality of life. Electrical stimulation techniques have emerged as promising interventions to address mental stress, depression, and anxiety. This systematic review investigates the impact of different electrical stimulation approaches on these types of disorders. The review synthesizes data from 30 studies, revealing promising findings and identifying several research gaps and challenges. The results indicate that electrical stimulation has the potential to alleviate symptoms of anxiety, depression, and tension, although the degree of efficacy varies among different patient populations and modalities. Nevertheless, the findings also underscore the necessity of standardized protocols and additional research to ascertain the most effective treatment parameters. There is also a need for integrated methodologies that combine hybrid EEG-fNIRS techniques with stress induction paradigms, the exploration of alternative stimulation modalities beyond tDCS, and the investigation of the combined effects of stimulation on stress. Despite these challenges, the growing body of evidence underscores the potential of electrical stimulation as a valuable tool to manage mental stress, depression, and anxiety, paving the way for future advancements in this field.

Harnessing Brainwave Entrainment: A Non-invasive Strategy To Alleviate Neurological Disorder Symptoms

From 1990-2019, the burden of neurological disorders varied considerably across countries and regions. Psychiatric disorders, often emerging in early to mid-adulthood, are linked to late-life neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. Individuals with conditions such as Major Depressive Disorder, Anxiety Disorder, Schizophrenia, and Bipolar Disorder face up to four times higher risk of developing neurodegenerative disorders. Contrarily, 65 % of those with neurodegenerative conditions experience severe psychiatric symptoms during their illness. Further, the limitation of medical resources continues to make this burden a significant global and local challenge. Therefore, brainwave entrainment provides therapeutic avenues for improving the symptoms of diseases. Brainwaves are rhythmic oscillations produced either spontaneously or in response to stimuli. Key brainwave patterns include gamma, beta, alpha, theta, and delta waves, yet the underlying physiological mechanisms and the brain's ability to shift between these dynamic states remain areas for further exploration. In neurological disorders, brainwaves are often disrupted, a phenomenon termed "oscillopathy". However, distinguishing these impaired oscillations from the natural variability in brainwave activity across different regions and functional states poses significant challenges. Brainwave-mediated therapeutics represents a promising research field aimed at correcting dysfunctional oscillations. Herein, we discuss a range of non-invasive techniques such as non-invasive brain stimulation (NIBS), neurologic music therapy (NMT), gamma stimulation, and somatosensory interventions using light, sound, and visual stimuli. These approaches, with their minimal side effects and cost-effectiveness, offer potential therapeutic benefits. When integrated, they may not only help in delaying disease progression but also contribute to the development of innovative medical devices for neurological care.

Non-invasive brain stimulation in the treatment of generalized anxiety disorder: A systematic review and meta-analysis

BACKGROUND

Non-invasive brain stimulation (NIBS), including repetitive transcranial magnetic stimulation (rTMS), continuous theta-burst stimulation (cTBS), and transcranial direct current stimulation (tDCS), is an emerging intervention that has been used to treat various mental illnesses. However, previous studies have not comprehensively compared the efficacies of various NIBS modalities in alleviating anxiety symptoms among patients with generalized anxiety disorder (GAD). Therefore, this study conducted a systematic review and meta-analysis to assess the efficacy of NIBS for patients with GAD.

METHODS

A systematic search of four major bibliographic databases (Embase, PubMed, Web of Science and The Cochrane Library) was conducted from inception dates to November 26, 2023 to identify eligible studies. The data were analyzed using a random-effects model.

RESULTS

Seven randomized controlled trials (RCTs) were included in the meta-analysis. Significant differences were found in changes in Hamilton anxiety rating scale (HARS) scores, study-defined response, and remission between the intervention and control groups. Moreover, the intervention groups experienced a significantly higher frequency of headaches.

CONCLUSION

The results revealed that interventions improved GAD compared to control groups. cTBS and rTMS exhibited better treatment efficacy than tDCS, which did not appear to have a significant therapeutic effect. Longer follow-up periods and larger sample sizes are required in future RCTs.

TRIAL REGISTRATION

This meta-analysis was conducted in accordance with PRISMA guidelines and registered at PROSPERO (https://www.crd.york.ac.uk/PROSPERO/, CRD42023466285).

Immediate and long-term efficacy of transcranial direct current stimulation (tCDS) in obsessive-compulsive disorder, posttraumatic stress disorder and anxiety disorders: a systematic review and meta-analysis

Currently, there is still debate over the effectiveness of transcranial direct current stimulation (tDCS) in treating obsessive-compulsive disorder (OCD), posttraumatic stress disorder (PTSD) and anxiety disorders (ADs). To investigate the immediate and long-term effectiveness of tDCS in these diseases, we conducted a systematic review and quantitative analysis of existing literature on the treatment of OCD, PTSD, and ADs with tDCS. Following the PRISMA guidelines, we searched seven electronic databases and systematically retrieved articles published from May 2012 to June 2024 that compared the effects of active tDCS with sham stimulation in the treatment of these disorders. We included primary outcome measures such as the change scores in disorder-specific and general anxiety symptoms before and after treatment, as well as secondary outcomes such as changes in disorder-specific and general anxiety symptoms at follow-up. We also assessed the impact of tDCS on depressive symptoms. Fifteen papers met the eligibility criteria. Overall, the results of meta-analysis indicated that tDCS had a high effect in improving specific symptoms (SMD = -0.73, 95% CI: -1.09 to -0.37) and general anxiety symptoms (SMD = -0.75; 95% CI: -1.23 to -0.26) in OCD, PTSD and ADs, with effects lasting up to 1 month and showing a moderate effect size. Furthermore, tDCS demonstrated immediate and significant alleviation of depressive symptoms in these diseases. This study concludes that tDCS can serve as a non-invasive brain stimulation technology for treating these disorders, and the therapeutic effects can be maintained for a period of time.

Evaluating the effects of tDCS on depressive and anxiety symptoms from a transdiagnostic perspective: a systematic review and meta-analysis of randomized controlled trials

Depressive and anxiety symptoms are prevalent among patients with various clinical conditions, resulting in diminished emotional well-being and impaired daily functioning. The neural mechanisms underlying these symptoms, particularly across different disorders, remain unclear, limiting the effectiveness of conventional treatments. Therefore, it is crucial to elucidate the neural underpinnings of depressive and anxiety symptoms and investigate novel, effective treatments across clinical conditions. Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that can help understand the neural underpinnings of symptoms and facilitate the development of interventions, addressing the two research gaps at both neural and clinical levels. Thus, this systematic review and meta-analysis aims to evaluate the existing evidence regarding the therapeutic efficacy of tDCS in reducing depressive and anxiety symptoms among individuals with diverse clinical diagnoses. This review evaluated evidence from fifty-six randomized, sham-controlled trials that administered repeated tDCS sessions with a parallel design, applying a three-level meta-analytic model. tDCS targeting the left dorsolateral prefrontal cortex (DLPFC) at 2-mA intensity demonstrates moderate efficacy in alleviating depressive symptoms, identifying the left DLPFC as a transdiagnostic neural mechanism of depressive symptoms across clinical conditions. In comparison, the findings on anxiety symptoms demonstrate greater heterogeneity. tDCS over the left DLPFC is effective in reducing depressive symptoms and shows promising effects in alleviating anxiety symptoms among individuals with diverse diagnoses. These findings enhance our understanding of the neuropsychological basis of depressive and anxiety symptoms, laying the groundwork for the development of more effective tDCS interventions applicable across clinical conditions.

Combined EEG-tDCS approach in resting state to reduce comorbid anxiety and depressive symptoms in affective disorders: A sham-controlled pilot study

Continuous challenges have been imposed on mental health science by Anxiety and Depression disorders as the most prevalent and debilitating psychiatric conditions worldwide. Pharmacologic and cognitive behavioral therapies, either alone or in combination, have been considered as the first-line therapies, however, resistant symptomatology is prevalent in comorbid conditions with symptoms remaining after interventions. The demand for new therapeutic solutions has given space to the development of non-invasive brain stimulation techniques (NIBS), and the transmagnetic direct current stimulation (tDCS) has been reported as a safe and well-tolerated technique for the treatment of several mental health conditions, including Anxiety and Depression disorders. Relying on quantitative electroencephalography(qEEG)- tDCS approach, the current study aims to inspect the effect of tDCS intervention on patients who suffer from anxiety-depression comorbidity, in particular, the impact of tDCS intervention on qEEG spectral power activity and resting-state connectivity organization during eyes closed and eyes open protocols. QEEG data were acquired from eight patients suffering from moderate to severe anxiety-depression comorbid symptoms along with poor coping skills to manage stress and negative affect. Twelve control subjects allocated in the control group exhibiting low to moderate symptoms in both anxiety and depression conditions went also through the qEEG data acquisition. In addition, a sham-controlled study was conducted, and the patient group went through resting-state qEEG-tDCS neuromodulation once a week for ten weeks. Various-stage qEEG recordings were performed to inspect the efficacy of tDCS treatment during the modulation of brain regions involved in the regulation of affective responses. Our results demonstrated that after tDCS neuromodulation, the patients' groups exhibited decreased absolute power abnormalities over the left anterior cingulate cortex and reduced abnormal activity in the alpha band over posterior regions; improved functional connectivity indexes; decreased anxiety and depressive scores while positive affect score was improved. Besides the promising improvements, our study did not find a significant tDCS effect on perceived stress and negative affect scores. Consistently, significant differences in absolute spectral power over the left anterior cingulate cortex were detected among the patient group, as compared to the controls, as expected. Therefore, our study offers preliminary data to understand the neuroplasticity changes that potentially result from the manipulation of cortical excitability during affective regulation protocols followed by the consequent decrease of comorbid anxiety and depressive symptomatology. The pilot study was followed by prospective registration with ChiCTR2200062142.

Transcranial Direct Current Stimulation for Anxiety During Laparoscopic Colorectal Cancer Surgery: A Randomized Clinical Trial

Importance

Perioperative anxiety is prevalent among patients undergoing surgical treatment of cancer and often influences their prognosis. Transcranial direct current stimulation (tDCS) has shown potential in the treatment of various anxiety-related disorders, but data on the impact of tDCS on perioperative anxiety are limited.

Objective

To evaluate the effect of tDCS in reducing perioperative anxiety among patients undergoing laparoscopic colorectal cancer (CRC) resection.

Design, Setting, And Participants

This randomized clinical trial was conducted from March to August 2023 at the Affiliated Hospital of Xuzhou Medical University. Patients aged 18 years or older undergoing elective laparoscopic radical resection for CRC were randomly assigned to either the active tDCS group or the sham tDCS group. Intention-to-treat data analysis was performed in September 2023.

Interventions

Patients were randomly assigned to receive 2 sessions of either active tDCS or sham tDCS over the left dorsolateral prefrontal cortex on the afternoon of the day before the operation and in the morning of the day of operation.

Main Outcomes and Measures

The main outcome was the incidence of perioperative anxiety from the day of the operation up to 3 days after the procedure, as measured using the Hospital Anxiety and Depression Scale-Anxiety (HADS-A) subscale (range: 0-21, with higher scores indicating more anxiety). Secondary outcomes included postoperative delirium (assessed by the Confusion Assessment Method or Confusion Assessment Method intensive care unit scale); pain (assessed by the 10-point Numeric Rating Scale [NRS], with scores ranging from 0 [no pain] to 10 [worst pain]); frailty (assessed by the Fatigue, Resistance, Ambulation, Illness and Loss of Weight [FRAIL] Index, with scores ranging from 0 [most robust] to 5 [most frail]; and sleep quality (assessed by the Pittsburgh Sleep Quality Index [PSQI], with scores ranging from 0 to 21 and higher scores indicating worse sleep quality) after the 2 sessions of the tDCS intervention.

Results

A total of 196 patients (mean [SD] age, 63.5 [11.0] years; 124 [63.3%] men) were recruited and randomly assigned to the active tDCS group (98 patients) or the sham tDCS group (98 patients). After the second tDCS intervention on the day of the operation, the incidence of perioperative anxiety was 38.8% in the active tDCS group and 70.4% in the sham tDCS group (relative risk, 0.55 [95% CI, 0.42-0.73]; P < .001). Patients in the active tDCS group vs the sham tDCS group were less likely to have postoperative delirium (8.2% vs 25.5%) and, at 3 days after the operation, had lower median (IQR) pain scores (NRS, 1.0 [1.0-1.0] vs 2.0 [2.0-2.0]), better median (IQR) sleep quality scores (PSQI, 10.5 [10.0-11.0] vs 12.0 [11.0-13.0]), and lower median (IQR) FRAIL Index (2.0 [1.0-2.0] vs 2.0 [2.0-3.0]).

Conclusions and Relevance

Findings of this randomized clinical trial indicate that administration of 2 preoperative sessions of tDCS was associated with a decreased incidence of perioperative anxiety in patients undergoing elective CRC resection. Active tDCS was also associated with better anxiety scores, pain levels, and sleep quality as well as reduced postoperative delirium and frailty. The findings suggest that tDCS may be a novel strategy for improving perioperative anxiety in patients undergoing CRC resection.

Trial Registration

Chinese Clinical Trial Register Identifier: ChiCTR2300068859.

tDCS reduces depression and state anxiety symptoms in older adults from the augmenting cognitive training in older adults study (ACT)

BACKGROUND

Pharmacological interventions for depression and anxiety in older adults often have significant side effects, presenting the need for more tolerable alternatives. Transcranial direct current stimulation (tDCS) is a promising non-pharmacological intervention for depression in clinical populations. However, its effects on depression and anxiety symptoms, particularly in older adults from the general public, are understudied.

OBJECTIVE

We conducted a secondary analysis of the Augmenting Cognitive Training in Older Adults (ACT) trial to assess tDCS efficacy in reducing psychological symptoms in older adults. We hypothesized that active stimulation would yield greater reductions in depression and state anxiety compared to sham post-intervention and at the one-year follow-up. We also explored tDCS effects in subgroups characterized by baseline symptom severity.

METHODS

A sample of 378 older adults recruited from the community completed a 12-week tDCS intervention with cognitive or education training. Electrodes were placed at F3/F4, and participants received active or sham tDCS during training sessions. We assessed the association between tDCS group and changes in depression, state anxiety, and trait anxiety from baseline to post-intervention and one-year controlling for covariates.

RESULTS

The active tDCS group demonstrated greater reductions in depression and state anxiety compared to sham post-intervention, particularly in individuals with mild depression and moderate/severe state anxiety at baseline. Furthermore, the active tDCS group with moderate/severe state anxiety maintained greater symptom reductions at one-year.

CONCLUSIONS

tDCS effectively reduced depression and state anxiety symptoms in a large sample of older adults. These findings highlight the importance of considering symptom severity when identifying those who may benefit most from this intervention.

Pre-clinical indications of brain stimulation treatments for non-affective psychiatric disorders, a status update

Over the past two decades noninvasive brain stimulation (NIBS) techniques have emerged as powerful therapeutic options for a range of psychiatric and neurological disorders. NIBS are hypothesized to rebalance pathological brain networks thus reducing symptoms and improving functioning. This development has been fueled by controlled studies with increasing size and rigor aiming to characterize how treatments induce clinically effective change. Clinical trials of NIBS for specific indications have resulted in federal approval for unipolar depression, bipolar depression, smoking cessation, and obsessive-compulsive disorder in the United States, and several other indications worldwide. As a rapidly emerging field, there are numerous pre-clinical indications currently in development using a variety of electrical and magnetic, non-convulsive, and convulsive approaches. This review discusses the state-of-the-science surrounding promising avenues of NIBS currently in pre-approval stages for non-affective psychiatric disorders. We consider emerging therapies for psychosis, anxiety disorders, obsessive-compulsive disorder, and borderline personality disorder, utilizing transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and magnetic seizure therapy (MST), with an additional brief section for early-stage techniques including transcranial focused ultrasound stimulation (tFUS) and transcranial alternating current stimulation (tACS). As revealed in this review, there is considerable promise across all four psychiatric indications with different NIBS approaches. Positive findings are notable for the treatment of psychosis using tDCS, MST, and rTMS. While rTMS is already FDA approved for the treatment of obsessive-compulsive disorder, methodologies such as tDCS also demonstrate potential in this condition. Emerging techniques show promise for treating non-affective disorders likely leading to future regulatory approvals.

Effects of multisession cathodal transcranial direct current stimulation with cognitive training on sociocognitive functioning and brain dynamics in autism: A double-blind, sham-controlled, randomized EEG study

BACKGROUND

Few treatment options are available for targeting core symptoms of autism spectrum disorder (ASD). The development of treatments that target common neural circuit dysfunctions caused by known genetic defects, namely, disruption of the excitation/inhibition (E/I) balance, is promising. Transcranial direct current stimulation (tDCS) is capable of modulating the E/I balance in healthy individuals, yet its clinical and neurobiological effects in ASD remain elusive.

OBJECTIVE

This double-blind, randomized, sham-controlled trial investigated the effects of multisession cathodal prefrontal tDCS coupled with online cognitive remediation on social functioning, information processing efficiency and the E/I balance in ASD patients aged 14-21 years.

METHODS

Sixty individuals were randomly assigned to receive either active or sham tDCS (10 sessions in total, 20 min/session, stimulation intensity: 1.5 mA, cathode: F3, anode: Fp2, size of electrodes: 25 cm2) combined with 20 min of online cognitive remediation. Social functioning, information processing efficiency during cognitive tasks, and theta- and gamma-band E/I balance were measured one day before and after the treatment.

RESULTS

Compared to sham tDCS, active cathodal tDCS was effective in enhancing overall social functioning [F(1, 58) = 6.79, p = .012, ηp2 = 0.105, 90% CI: (0.013, 0.234)] and information processing efficiency during cognitive tasks [F(1, 58) = 10.07, p = .002, ηp2 = 0.148, 90% CI: (0.034, 0.284)] in these individuals. Electroencephalography data showed that this cathodal tDCS protocol was effective in reducing the theta-band E/I ratio of the cortical midline structures [F(1, 58) = 4.65, p = .035, ηp2 = 0.074, 90% CI: (0.010, 0.150)] and that this reduction significantly predicted information processing efficiency enhancement (b = -2.546, 95% BCa CI: [-4.979, -0.113], p = .041).

CONCLUSION

Our results support the use of multisession cathodal tDCS over the left dorsolateral prefrontal cortex combined with online cognitive remediation for reducing the elevated theta-band E/I ratio in sociocognitive information processing circuits in ASD patients, resulting in more adaptive regulation of global brain dynamics that is associated with enhanced information processing efficiency after the intervention.

820-nm Transcranial Near-infrared Stimulation on the Left DLPFC Relieved Anxiety: A Randomized, Double-blind, Sham-controlled Study

OBJECTIVE

Generalized anxiety disorder (GAD) is a chronic mood disease associated with abnormal brain network connections, including decreased activity in the left dorsolateral prefrontal cortex (DLPFC). Cortical excitability can be increased with 820-nm transcranial near-infrared stimulation (tNIRS), while transcranial magnetic stimulation with electroencephalography (TMS-EEG) can help evaluate time-varying brain network connectivity. A randomized, double-blind, sham-controlled trial was conducted to assess the efficacy of tNIRS on the left DLPFC and the impact on time-varying brain network connections in GAD patients.

METHODS

A total of 36 GAD patients were randomized to receive active or sham tNIRS for 2 weeks. Clinical psychological scales were assessed before, after, and at the 2-, 4-, and 8-week follow-ups. TMS-EEG was performed for 20minutes before and immediately after tNIRS treatment. The healthy controls did not receive tNIRS and only had TMS-EEG data collected once in the resting state.

RESULTS

The Hamilton Anxiety Scale (HAMA) scores of the active stimulation group decreased post-treatment compared with the sham group (P=0.021). The HAMA scores of the active stimulation group at the 2-, 4-, and 8-week follow-up assessments were lower than those before treatment (P<0.05). The time-varying EEG network pattern showed an information outflow from the left DLPFC and the left posterior temporal region after active treatment.

CONCLUSION

Herein, 820-nm tNIRS targeting the left DLPFC had significant positive effects on therapy for GAD that lasted at least 2 months. tNIRS may reverse the abnormality of time-varying brain network connections in GAD.

Comparison of the Effect of Chlordiazepoxide and Transcranial Alternating Current Stimulation on Blood Potassium Loss Due to Preoperative Anxiety

PURPOSE

This study evaluated and compared the effect of chlordiazepoxide and transcranial alternating current stimulation (tACS) on changes in blood potassium levels caused by preoperative anxiety.

DESIGN

This randomized, double-blind placebo control study was performed on 100 patients undergoing surgery with the American Society of Anesthesiologists physical status (ASA I) who went through surgery for the first time.

METHODS

Patients were classified into four groups of real or sham tACS, chlordiazepoxide, and placebo. The Amsterdam Preoperative Anxiety information Scale (APAIS) and serum potassium levels were used to collect data. The results were analyzed using the Kolmogorov-Smirnov tests, independent t test, Pearson correlation, and χ² test.

FINDINGS

There was no baseline difference between the groups. A significant difference was found between real tACS and the chlordiazepoxide group in plasma potassium level (P = .017).

CONCLUSIONS

The results showed that real tACS was more effective than chlordiazepoxide in preventing the decrease of plasma potassium level in the preoperative period. Assessing the efficacy of the other types of brain electrical interventions is suggested for future studies.

Contemporary Approaches Toward Neuromodulation of Fear Extinction and Its Underlying Neural Circuits

Neuroscience and neuroimaging research have now identified brain nodes that are involved in the acquisition, storage, and expression of conditioned fear and its extinction. These brain regions include the ventromedial prefrontal cortex (vmPFC), dorsal anterior cingulate cortex (dACC), amygdala, insular cortex, and hippocampus. Psychiatric neuroimaging research shows that functional dysregulation of these brain regions might contribute to the etiology and symptomatology of various psychopathologies, including anxiety disorders and post traumatic stress disorder (PTSD) (Barad et al. Biol Psychiatry 60:322-328, 2006; Greco and Liberzon Neuropsychopharmacology 41:320-334, 2015; Milad et al. Biol Psychiatry 62:1191-1194, 2007a, Biol Psychiatry 62:446-454, b; Maren and Quirk Nat Rev Neurosci 5:844-852, 2004; Milad and Quirk Annu Rev Psychol 63:129, 2012; Phelps et al. Neuron 43:897-905, 2004; Shin and Liberzon Neuropsychopharmacology 35:169-191, 2009). Combined, these findings indicate that targeting the activation of these nodes and modulating their functional interactions might offer an opportunity to further our understanding of how fear and threat responses are formed and regulated in the human brain, which could lead to enhancing the efficacy of current treatments or creating novel treatments for PTSD and other psychiatric disorders (Marin et al. Depress Anxiety 31:269-278, 2014; Milad et al. Behav Res Ther 62:17-23, 2014). Device-based neuromodulation techniques provide a promising means for directly changing or regulating activity in the fear extinction network by targeting functionally connected brain regions via stimulation patterns (Raij et al. Biol Psychiatry 84:129-137, 2018; Marković et al. Front Hum Neurosci 15:138, 2021). In the past ten years, notable advancements in the precision, safety, comfort, accessibility, and control of administration have been made to the established device-based neuromodulation techniques to improve their efficacy. In this chapter we discuss ten years of progress surrounding device-based neuromodulation techniques-Electroconvulsive Therapy (ECT), Transcranial Magnetic Stimulation (TMS), Magnetic Seizure Therapy (MST), Transcranial Focused Ultrasound (TUS), Deep Brain Stimulation (DBS), Vagus Nerve Stimulation (VNS), and Transcranial Electrical Stimulation (tES)-as research and clinical tools for enhancing fear extinction and treating PTSD symptoms. Additionally, we consider the emerging research, current limitations, and possible future directions for these techniques.

Transcranial Direct Current Stimulation (tDCS): Pain Management in End-Stage Renal Disease - Report of an Early Randomized Controlled Trial

CONTEXT

Chronic pain in end-stage renal disease (ESRD) is an increasingly neglected clinical problem affecting more than 60% of patients. Long-term chronic pain could be associated with brain imbalance in circuits of pain matrix and is associated with poor quality of life (QoL) and mood disturbance.

OBJECTIVES

The aim of this study was evaluating the effects of transcranial direct current stimulation (tDCS) on pain, QoL, depression, anxiety and affectivity in ESRD patients undergoing hemodialysis (HD).

METHODS

This double-blind, randomized, sham-controlled trial included 30 patients with chronic pain undergoing HD. Participants were allocated to Active tDCS and Sham tDCS and received ten non-consecutive sessions of anodal motor cortex stimulation (M1/Sp2 montage) at 2 mA intensity for 20 min. The primary outcome was pain assessed using numeric rating scale (NRS) and collected at baseline, immediately after the 10th day of intervention, one week, two weeks, and four weeks after the last stimulation. Secondary outcomes included QoL, depression, anxiety and affectivity collected before and after intervention.

RESULTS

A mixed ANOVA model showed significant interaction between group and time on pain F(4.112) = 3.106, P = 0.01 with main effects of group (P = 0.03). Before and after intervention, a significant improvement was observed in QoL (P = 0.009), general health (P = 0.03), fatigue (P = 0.05), symptoms (P = 0.05) depression (P = 0.01) and anxiety (P = 0.01). No difference was found for affectivity.

CONCLUSION

Anodal tDCS over the motor cortex emerges as a potential therapeutic approach for improving pain, QoL, and mood in patients with ESRD.

Transcranial direct current stimulation does not improve clinical and neurophysiological outcomes in panic disorder: A randomized sham-controlled trial

AIM

Emerging evidence suggests that transcranial direct current stimulation (tDCS) has anxiolytic effects and may enhance emotional processing of threat and reduce threat-related attentional bias. Panic disorder (PD) is considered to be a fear network disorder along with prefrontal activity alterations. We aim to assess the effect of tDCS on clinical and physiological parameters in PD for the first time.

METHODS

In this triple-blind randomized sham-controlled pilot study, 30 individuals with PD were allocated into active and sham groups to receive 10 sessions of tDCS targeting the dorsolateral prefrontal cortex bilaterally at 2 mA for 20-min duration over 2 weeks. The clinical severity, threat-related attentional bias, interoceptive accuracy, and emotional recognition were assessed before, immediately after, and 1 month after tDCS.

RESULTS

Active tDCS, in comparison to sham, did not elicit more favorable clinical and neuropsychological/physiological outcomes in PD.

CONCLUSION

The present study provides the first clinical and neurobehavioral results of prefrontal tDCS in PD and indicates that prefrontal tDCS was not superior to sham in PD.

Neuromodulation Treatments of Pathological Anxiety in Anxiety Disorders, Stressor-Related Disorders, and Major Depressive Disorder: A Dimensional Systematic Review and Meta-Analysis

Background

Pathological anxiety is responsible for major functional impairments and resistance to conventional treatments in anxiety disorders (ADs), posttraumatic stress disorder (PTSD) and major depressive disorder (MDD). Focal neuromodulation therapies such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS) are being developed to treat those disorders.

Methods

We performed a dimensional systematic review and meta-analysis to assess the evidence of the efficacy of TMS, tDCS and DBS in reducing anxiety symptoms across ADs, PTSD and MDD. Reports were identified through systematic searches in PubMed/Medline, Scopus and Cochrane library (inception to November 2020), followed by review according to the PRISMA guidelines. Controlled clinical trials examining the effectiveness of brain stimulation techniques on generic anxiety symptoms in patients with ADs, PTSD or MDD were selected.

Results

Nineteen studies (RCTs) met inclusion criteria, which included 589 participants. Overall, focal brain activity modulation interventions were associated with greater reduction of anxiety levels than controls [SMD: -0.56 (95% CI, -0.93 to-0.20, I 2 = 77%]. Subgroup analyses revealed positive effects for TMS across disorders, and of focal neuromodulation in generalized anxiety disorder and PTSD. Rates of clinical responses and remission were higher in the active conditions. However, the risk of bias was high in most studies.

Conclusions

There is moderate quality evidence for the efficacy of neuromodulation in treating pathological anxiety.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=233084, identifier: PROSPERO CRD42021233084. It was submitted on January 29th, 2021, and registered on March 1st, 2021. No amendment was made to the recorded protocol. A change was applied for the subgroup analyses based on target brain regions, we added the putative nature (excitatory/inhibitory) of brain activity modulation.

Effects of tDCS on Depression and Comorbid Generalized Anxiety Disorder: A Brain Function Imaging Case Report

Background

Transcranial direct current stimulation (tDCS) is a type of non-invasive brain stimulation technique that has proven effective for neuropsychiatric disorders. Generalized anxiety disorder (GAD) and depression are common psychiatric disorders that often are comorbid, meaning they occur simultaneously. Current evidence supports the value of tDCS for GAD. The objectives of this report is to explore the effect of tDCS on clinical symptoms and cerebral function in a patient with comorbid GAD and depression.

Methods

Our subject was a semiprofessional athlete diagnosed with comorbid GAD and depression. Symptoms included palpitations, sweating, continuous tension, and anxiety. We designed a B-A-B experimental protocol and used the Beck Anxiety Index (BAI), Beck Depression Index (BDI), and Pittsburgh Sleep Quality Index (PSQI) as assessment tools. Treatment consisted of 2 series of 15 days each, separated by a 3-week washout period. We collected functional near-infrared spectroscopy (fNIRS) data before and after both series, as well as fNIRS data immediately after the first treatment in both series. In addition, we collected functional magnetic resonance imaging data before and after the second series.

Results

After the first series, the scores of the three questionnaires (BAI, BDI and PSQI) decreased significantly, which showed the trend of improvement. The functional connection of bilateral prefrontal partial channels decreased significantly immediately after tDCS treatment. The results of the fNIRS before the second-series treatment showed that prefrontal connectivity returned to the state before the first intervention after the washout period. The results of the fNIRS after the second series treatment showed that the symptoms of depression and anxiety alleviated. The results of the fNIRS showed that the prefrontal connectivity decreased again.

Conclusion

In the treatment of comorbid GAD and depression, tDCS can alleviate symptoms and improve sleep quality and social behavior. Brain imaging is widely used to observe functional changes by tDCS such as fMRI and fNIRS. The study also showed that fNIRS can be a safe, simple, and efficient method to assess brain activity.

Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex for Treatment of Neuropsychiatric Disorders

Background

The dorsolateral prefrontal cortex (DLPFC) is a key node of the frontal cognitive circuit. It is involved in executive control and many cognitive processes. Abnormal activities of DLPFC are likely associated with many psychiatric diseases. Modulation of DLPFC may have potential beneficial effects in many neural and psychiatric diseases. One of the widely used non-invasive neuromodulation technique is called transcranial direct current stimulation (or tDCS), which is a portable and affordable brain stimulation approach that uses direct electrical currents to modulate brain functions.

Objective

This review aims to discuss the results from the past two decades which have shown that tDCS can relieve clinical symptoms in various neurological and psychiatric diseases.

Methods

Here, we performed searches on PubMed to collect clinical and preclinical studies that using tDCS as neuromodulation technique, DLPFC as the stimulation target in treating neuropsychiatric disorders. We summarized the stimulation sites, stimulation parameters, and the overall effects in these studies.

Results

Overall, tDCS stimulation of DLPFC could alleviate the clinical symptoms of schizophrenia, depression, drug addiction, attention deficit hyperactivity disorder and other mental disorders.

Conclusion

The stimulation parameters used in these studies were different from each other. The lasting effect of stimulation was also not consistent. Nevertheless, DLPFC is a promising target for non-invasive stimulation in many psychiatric disorders. TDCS is a safe and affordable neuromodulation approach that has potential clinical uses. Larger clinical studies will be needed to determine the optimal stimulation parameters in each condition.

Effects of non-invasive brain stimulation in multiple sclerosis: systematic review and meta-analysis

Objective:

The objective of this meta-analysis was to summarize evidence on the therapeutic effects of non-invasive brain stimulation (NIBS) on core symptoms of multiple sclerosis (MS). Specifically, findings from studies deploying transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) protocols were summarized in this review.

Methods:

We systematically searched articles published in four databases, until 31 May 2021, which compared the effects of active tDCS or rTMS with sham intervention in MS patients. We used a random-effects model for this meta-analysis. Meta-regression and subgroup meta-analysis were used to examine the effects of stimulation dose and different stimulation protocols, respectively.

Results:

Twenty-five randomized controlled trials (RCTs) were included in this review, consisting of 19 tDCS and 6 rTMS studies. tDCS led to a significant and immediate reduction of fatigue with a large effect size (Hedges’s g = −0.870, 95% confidence intervals (CI) = [−1.225 to −0.458], number needed to treat (NNT) = 2). Particularly, a subgroup analysis showed that applying tDCS over the left DLPFC and bilateral S1 led to fatigue reductions compared to sham stimulation. Furthermore, tDCS had favorable effects on fatigue in MS patients with low physical disability but not those with high physical disability, and additionally improved cognitive function. Finally, whereas rTMS was observed to reduce muscle spasticity, these NIBS protocols showed no further effect on MS-associated pain and mood symptoms.

Conclusion:

tDCS in MS alleviates fatigue and improves cognitive function whereas rTMS reduces muscle spasticity. More high-quality studies are needed to substantiate the therapeutic effects of different NIBS protocols in MS.

Longitudinal study of impact of medication for opioid use disorder on Hamilton Depression Rating Scale

OBJECTIVE

This study aimed to evaluate the longitudinal treatment effect on depression measured by Hamilton Depression Rating Scale (HAM-D) score in a randomized clinical trial for the treatment of opioid use disorder (OUD).

METHODS

We conducted a secondary data analysis of data from the National Institute on Drug Abuse's Clinical Trials Network Protocol-0051. Patients with OUD (N = 570) were randomized to receive buprenorphine/naloxone (BUP-NX, n = 287) or extended-release naltrexone injection (XR-NTX, n = 283). The HAM-D score was completed at baseline and follow-up visit up to 36 weeks. A linear mixed model analysis was performed for log transformed HAM-D score and a generalized linear mixed model analysis was conducted for depression status.

RESULTS

Compared with BUP-NX, subjects randomized to XR-NTX had higher HAM-D scores at weeks 1 and 3 (p<0.05). There were significant interactions between treatment and visit on HAM-D score and depression status during the first four weeks of treatments in individuals without lifetime major depressive disorder (MDD). Past year cocaine use was associated with HAM-D score and depression status just in individuals without MDD, whereas past year cannabis use was associated with HAM-D score and depression status just in individuals with MDD. Past year amphetamine use was associated with HAM-D score just in individuals without MDD, however, lifetime anxiety was associated with HAM-D scores regardless of MDD.

CONCLUSION

When prescribing XR-NTX, particularly in the first month of treatment, it is essential to monitor for depressive symptoms. Screening for depression and multiple substance abuse may help clinicians identify appropriate treatment.

Transcranial Electrical Stimulation for Relief of Peripartum Mental Health Disorders in Women Undergoing Cesarean Section With Combined Spinal-Epidural Anesthesia: A Pilot Randomized Clinical Trial

OBJECTIVE

This study aimed to explore transcranial electrical stimulation (tES) to relieve peripartum anxiety and depressive symptoms in women undergoing cesarean section with combined spinal-epidural anesthesia.

METHODS

This double-blind, randomized, sham-controlled trial was conducted in the Affiliated Hospital of Xuzhou Medical University from March 2021 and May 2021. One hundred and forty-eight full-term parturients giving birth by elective cesarean section were selected, and 126 were included in the intent-to-treat analysis. Parturients were provided standardized anesthesia and randomized to the active-tES (a-tES) group and sham-tES group. Parturients and outcome assessors were blinded to treatment allocation. The primary outcome was the changes in peripartum mental health disorders, including anxiety, assessed by the Pregnancy-Related Anxiety Questionnaire-Revised 2 (PRAQ-R2). Secondary outcomes included peripartum depressive symptoms, assessed by the Edinburgh Postnatal Depression Scale (EPDS), maternal satisfaction, fatigue level, sleep quality index, and pain score during and after operation. Data were collected before entering the operating room (T0), between post-anesthesia and pre-surgery (T1), before leaving the operating room (T2), and at 24 h post-surgery (T3).

RESULTS

One hundred and twenty-six eligible parturients were enrolled in the two groups: a-tES group (N = 62) and sham-tES group (N = 64). Treatment with tES resulted in significantly lower scores of anxiety compared with sham-tES (T2: P < 0.001; T3: P = 0.001). Moreover, the a-tES groups showed a significant reduction in depression scores (T2: P = 0.003; T3: P = 0.032).

CONCLUSION

In this randomized pilot study, tES treatment is efficacious in alleviating peripartum anxiety and depressive symptoms in women undergoing cesarean section and has been demonstrated to be a novel strategy for improving peripartum mental health disorders.

CLINICAL TRIAL REGISTRATION

[www.chictr.org.cn], identifier [ChiCTR2000040963].

Brain Stimulation for Emotion Regulation in Adolescents With Psychiatric Disorders: Study Protocol for a Clinical-Transdiagnostical, Randomized, Triple-Blinded and Sham-Controlled Neurotherapeutic Trial

BACKGROUND

Anxiety, conduct and depressive disorders represent three highly prevalent psychiatric conditions in adolescents. A shared underpinning of these disorders is a shortcoming in emotion regulation, connected to the functioning of the ventromedial prefrontal cortex. Thus, an intervention able to target the suggested neural correlate seems to be highly desirable, aiming to hinder a maladaptive development of emotion regulation abilities and chronification of associated psychiatric disorders. As transcranial direct current stimulation (tDCS) was repeatedly demonstrated as a safe and non-invasive method to modulate specific brain activity, research is in demand to evaluate neurotherapeutic applications in adolescents with psychiatric disorders.

METHOD

This transdiagnostic, randomized, triple-blind and sham-controlled clinical neurostimulation trial primary aims to investigate if emotion regulation abilities are increased after tDCS in adolescents with psychiatric disorders. Secondly, disorder-specific changes in the anxiety, depression or conduct disorder will be investigated, as well as changes in quality of life, and cognitive and emotional functioning after tDCS intervention. We will include 108 adolescents with psychiatric disorders, displaying a substantial deficit in emotion regulation. Of these, one third each has to be primarily diagnosed with a depressive, anxiety or conduct disorder, respectively. Participants will be randomized to the experimental group (n = 54) receiving real anodal tDCS, or to the control group (n = 54) receiving sham tDCS. Brain stimulation will be applied for 20 min on five consecutive days twice targeting the ventromedial prefrontal cortex (vmPFC). Changes in emotion regulation, together with changes in disorder-specific clinical symptoms will be recorded by multi-informant psychological ratings. To inspect changes in behavior and gaze, computerized tasks and an eye tracker system will be used. Changes in brain responses to emotional and cognitive stimuli will be examined with three functional magnetic resonance imaging (fMRI) paradigms. In addition, a resting state MRI will be acquired to investigate possible changes in brain connectivity.

DISCUSSION

By investigating "emotion regulation" as transdiagnostic treatment target, this project is oriented toward the Research Domain Criteria framework with a dimensional view on mental illness. The study aims at investigating the potential of tDCS as non-invasive intervention for depressive, anxiety and conduct disorders in adolescents and broadening the scientific foundation for its clinical application.

CLINICAL TRIAL REGISTRATION

The study is ongoing and has been registered in the German Registry of Clinical Trials (DRKS-ID: DRKS00025601X) on the 28.06.2021.

Home-Based Transcranial Direct Current Stimulation for the Treatment of Symptoms of Depression and Anxiety in Temporal Lobe Epilepsy: A Randomized, Double-Blind, Sham-Controlled Clinical Trial

We conducted a double-blind randomized clinical trial in order to examine the effects and the safety of home-based transcranial direct current stimulation (tDCS) on depressive and anxious symptoms of patients with temporal lobe epilepsy (TLE). We evaluated 26 adults with TLE and depressive symptoms randomized into two different groups: active tDCS (tDCSa) and Sham (tDCSs). The patients were first submitted to 20 sessions of tDCS for 20 min daily, 5 days a week for 4 weeks and then received a maintenance tDCS application in the research laboratory once a week for 3 weeks. The intensity of the current was 2 mA, applied bilaterally over the dorsolateral prefrontal cortex, with the anode positioned on the left side and the cathode on the right side. Participants were evaluated on days 1, 15, 30, and 60 of the study using the Beck Depression Inventory II (BDI). A follow-up evaluation was performed 1 year after the end of treatment. They were also evaluated for quality of life and for anxious symptoms as secondary outcomes. The groups did not differ in clinical, socioeconomic or psychometric characteristics at the initial assessment. There was no statistically significant difference between groups regarding reported adverse effects, seizure frequency or dropouts. On average, between the 1st and 60th day, the BDI score decreased by 43.93% in the active group and by 44.67% in the Sham group (ΔBDIfinal – initial = −12.54 vs. −12.20, p = 0.68). The similar improvement in depressive symptoms observed in both groups was attributed to placebo effect and interaction between participants and research group and not to tDCS intervention per se. In our study, tDCS was safe and well tolerated, but it was not effective in reducing depressive or anxiety symptoms in patients with temporal lobe epilepsy.

Clinical Trial Registration: [ClinicalTrials.gov], identifier [NCT03871842].

The role of ventromedial and dorsolateral prefrontal cortex in attention and interpretation biases in individuals with general anxiety disorder (GAD): A tDCS study

BACKGROUND

and purpose of the study: Individuals with general anxiety disorder (GAD) have deficits in emotional and cognitive processing, including cognitive bias, which plays a causal role in anxiety. Hyperactivity of the ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) is assumed to be involved in cognitive bias. We aimed to explore the causal contribution of the dorsolateral and ventromedial prefrontal cortices (dlPFC, vmPFC) on cognitive bias via non-invasive brain stimulation, and expected a bias-reducing effect of cortical activity enhancement over these areas in GAD, with a larger contribution of the vmPFC to perceptual, and of the dlPFC to interpretation bias.

MATERIAL AND METHODS

The study was conducted in a randomized, single-blinded, and complete crossover design. Thirty-four adults with GAD, received transcranial direct current stimulation (tDCS) in 5 separate sessions (1.5 mA, 20 min) with the following electrode montages: anodal dlPFC/cathodal vmPFC, anodal vmPFC/cathodal dlPFC, anodal dlPFC/cathodal right shoulder, anodal vmPFC/cathodal left shoulder, and sham stimulation. During stimulation, in each session, participants performed the Dot-Probe and Reading Mind from Eyes tests to measure attention and interpretation biases.

RESULTS

A significant effect of stimulation condition on attention and interpretation biases was observed. Anodal vmPFC and dlPFC stimulation coupled with an extracranial cathodal electrode reduced attention bias to threat-related stimuli in the dot-probe test. Furthermore, anodal dlPFC/cathodal vmPFC stimulation reduced negative interpretation bias in reading from eyes test.

CONCLUSION

As suggested by the results of this study, both dlPFC and vmPFC are involved in cognitive bias in GAD, but with partially different roles. Anodal stimulation over the right vmPFC and the left dlPFC reduced attention bias, supporting the relevance of these areas for attention bias. For interpretation bias, the significant effect of anodal dlPFC/cathodal vmPFC stimulation, but only trendwise effect of anodal tDCS over the dlPFC combined with an extracephalic return electrode is in accordance with a predominant effect of the dlPFC on interpretation bias, but does not rule out an additional minor involvement of the vmPFC. Based on these results, a new model is suggested for the neural underpinnings of anxiety symptoms.

Effectiveness of noninvasive brain stimulation in the treatment of anxiety disorders: a meta-analysis of sham or behaviour-controlled studies

BACKGROUND

The possibility of using noninvasive brain stimulation to treat mental disorders has received considerable attention recently. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are considered to be effective treatments for depressive symptoms. However, no treatment recommendation is currently available for anxiety disorders, suggesting that evidence is still limited. We conducted a systematic review of the literature and a quantitative analysis of the effectiveness of rTMS and tDCS in the treatment of anxiety disorders.

METHODS

Following PRISMA guidelines, we screened 3 electronic databases up to the end of February 2020 for English-language, peer-reviewed articles that included the following: a clinical sample of patients with an anxiety disorder, the use of a noninvasive brain stimulation technique, the inclusion of a control condition, and pre/post scores on a validated questionnaire that measured symptoms of anxiety.

RESULTS

Eleven papers met the inclusion criteria, comprising 154 participants assigned to a stimulation condition and 164 to a sham or control group. We calculated Hedge's g for scores on disorder-specific and general anxiety questionnaires before and after treatment to determine effect size, and we conducted 2 independent random-effects meta-analyses. Considering the well-known comorbidity between anxiety and depression, we ran a third meta-analysis analyzing outcomes for depression scores. Results showed a significant effect of noninvasive brain stimulation in reducing scores on disorder-specific and general anxiety questionnaires, as well as depressive symptoms, in the real stimulation compared to the control condition.

LIMITATIONS

Few studies met the inclusion criteria; more evidence is needed to strengthen conclusions about the effectiveness of noninvasive brain stimulation in the treatment of anxiety disorders.

CONCLUSION

Our findings showed that noninvasive brain stimulation reduced anxiety and depression scores compared to control conditions, suggesting that it can alleviate clinical symptoms in patients with anxiety disorders.

Repeated anodal high-definition transcranial direct current stimulation over the left dorsolateral prefrontal cortex in mild cognitive impairment patients increased regional homogeneity in multiple brain regions

Transcranial direct current stimulation (tDCS) can improve cognitive function. However, it is not clear how high-definition tDCS (HD-tDCS) regulates the cognitive function and its neural mechanism, especially in individuals with mild cognitive impairment (MCI). This study aimed to examine whether HD-tDCS can modulate cognitive function in individuals with MCI and to determine whether the potential variety is related to spontaneous brain activity changes recorded by resting-state functional magnetic resonance imaging (rs-fMRI). Forty-three individuals with MCI were randomly assigned to receive either 10 HD-tDCS sessions or 10 sham sessions to the left dorsolateral prefrontal cortex (L-DLPFC). The fractional amplitude of low-frequency fluctuation (fALFF) and the regional homogeneity (ReHo) was computed using rs-fMRI data from all participants. The results showed that the fALFF and ReHo values changed in multiple areas following HD-tDCS. Brain regions with significant decreases in fALFF values include the Insula R, Precuneus R, Thalamus L, and Parietal Sup R, while the Temporal Inf R, Fusiform L, Occipital Sup L, Calcarine R, and Angular R showed significantly increased in their fALFF values. The brain regions with significant increases in ReHo values include the Temporal Inf R, Putamen L, Frontal Mid L, Precentral R, Frontal Sup Medial L, Frontal Sup R, and Precentral L. We found that HD-tDCS can alter the intensity and synchrony of brain activity, and our results indicate that fALFF and ReHo analysis are sensitive indicators for the detection of HD-tDCS during spontaneous brain activity. Interestingly, HD-tDCS increases the ReHo values of multiple brain regions, which may be related to the underlying mechanism of its clinical effects, these may also be related to a potential compensation mechanism involving the mobilization of more regions to complete a function following a functional decline.

Parsing the antidepressant effects of non-invasive brain stimulation and pharmacotherapy: A symptom clustering approach on ELECT-TDCS

BACKGROUND

Transcranial direct current stimulation (tDCS) presents small antidepressant efficacy at group level and considerable inter-individual variability of response. Its heterogeneous effects bring the need to investigate whether specific groups of patients submitted to tDCS could present comparable or larger improvement compared to pharmacotherapy. Aggregate measurements might be insufficient to address its effects.

OBJECTIVE

/Hypothesis: To determine the efficacy of tDCS, compared to pharmacotherapy and placebo, in depressive symptom clusters.

METHODS

Data from ELECT-TDCS (Escitalopram versus Electrical Direct-Current Therapy for Treating Depression Clinical Study, ClinicalTrials.gov, NCT01894815), in which antidepressant-free, depressed patients were randomized to receive 22 bifrontal tDCS (2 mA, 30 min) sessions (n = 94), escitalopram 20 mg/day (n = 91), or placebo (n = 60) over 10 weeks. Agglomerative hierarchical clustering identified "sleep/insomnia", "core depressive", "guilt/anxiety", and "atypical" clusters that were the dependent measure. Trajectories were estimated using linear mixed regression models. Effect sizes are expressed in raw HAM-D units. P-values were adjusted for multiple comparisons.

RESULTS

For core depressive symptoms, escitalopram was superior to tDCS (ES = -0.56; CI_95% = -0.94 to -0.17, p = .009), which was superior to placebo (ES = 0.49; CI_95% = 0.06 to 0.92, p = .042). TDCS but not escitalopram was superior to placebo in sleep/insomnia symptoms (ES = 0.87; CI_95% = 0.22 to 1.52, p = .015). Escitalopram but not tDCS was superior to placebo in guilt/anxiety symptoms (ES = 1.66; CI_95% = 0.58 to 2.75, p = .006). No active intervention was superior to placebo for atypical symptoms.

CONCLUSIONS

Pharmacotherapy and non-invasive brain stimulation produce distinct effects in depressive symptoms. TDCS or escitalopram could be chosen according to specific clusters of symptoms for a bigger response.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01894815.

Association between tDCS computational modeling and clinical outcomes in depression: data from the ELECT-TDCS trial

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation intervention investigated for the treatment of depression. Clinical results have been heterogeneous, partly due to the variability of electric field (EF) strength in the brain owing to interindividual differences in head anatomy. Therefore, we investigated whether EF strength was correlated with behavioral changes in 16 depressed patients using simulated electric fields in real patient data from a controlled clinical trial. We hypothesized that EF strength in the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC), brain regions implicated in depression pathophysiology, would be associated with changes in depression, mood and anxiety scores. SimNIBS were used to simulate individual electric fields based on the MRI structural T1-weighted brain scans of depressed subjects. Linear regression models showed, at the end of the acute treatment phase, that simulated EF strength was inversely associated with negative affect in the bilateral ACC (left: β = - 160.463, CI [- 291.541, - 29.385], p = 0.021; right: β = - 189.194, CI [- 289.479, - 88.910], p = 0.001) and DLPFC (left: β = - 93.210, CI [- 154.960, - 31.461], p = 0.006; right: β = - 82.564, CI [- 142.867, - 22.262], p = 0.011) and with depression scores in the left ACC (β = - 156.91, CI [- 298.51, - 15.30], p = 0.033). No association between positive affect or anxiety scores, and simulated EF strength in the investigated brain regions was found. To conclude, our findings show preliminary evidence that EF strength simulations might be associated with further behavioral changes in depressed patients, unveiling a potential mechanism of action for tDCS. Further studies should investigate whether individualization of EF strength in key brain regions impact clinical response.

Anxiety is associated with increased risk for atrial cardiopathy

Anxiety is common in patients with atrial fibrillation (AF). The mutual causal effect between anxiety and AF is expected with limited evidence. Atrial cardiopathy is a term to describe structural or electrophysiological atrium abnormality that precedes the onset of AF. This study aimed to investigate the association of anxiety with atrial cardiopathy, giving a clue to the causal relationship of this mind-heart link. This cross-sectional study analyzed 532 patients who were free of AF, atrial flutter, stroke, acute coronary syndrome and valvular heart disease. Atrial cardiopathy was defined as P-wave terminal force in lead V1 > 5000 μV·ms on electrocardiogram or severe left atrial enlargement on echocardiogram. Generalized anxiety disorder was ascertained by a score of > 17/56 on Hamilton anxiety rating scale. Multivariable logistic regression was used to explore the association of anxiety with atrial cardiopathy. A total of 65(12.2%) patients had atrial cardiopathy and 53(10.0%) had generalized anxiety disorder, respectively. Those with atrial cardiopathy were older (74.0 vs 67.0, P < 0.001), had a bigger left ventricular posterior wall thickness (10.1 vs 9.7 mm, P = 0.030), and had a higher prevalence of hypertension (83.1% vs 65.5%, P = 0.005), premature complexes (20.0% vs 6.2%, P < 0.001), and generalized anxiety disorder (20.0% vs 8.6%, P = 0.004), respectively. Multivariable logistic regression showed the significant association of anxiety with atrial cardiopathy (OR 2.788; 95% CI 1.304-5.960, P = 0.008), independent of confounding factors. Anxiety is independently associated with atrial cardiopathy. This association indicates the triggering effect of anxiety on atrial remodeling.

Applications of Non-invasive Neuromodulation for the Management of Disorders Related to COVID-19

Background: Novel coronavirus disease (COVID-19) morbidity is not restricted to the respiratory system, but also affects the nervous system. Non-invasive neuromodulation may be useful in the treatment of the disorders associated with COVID-19. Objective: To describe the rationale and empirical basis of the use of non-invasive neuromodulation in the management of patients with COVID-10 and related disorders. Methods: We summarize COVID-19 pathophysiology with emphasis of direct neuroinvasiveness, neuroimmune response and inflammation, autonomic balance and neurological, musculoskeletal and neuropsychiatric sequela. This supports the development of a framework for advancing applications of non-invasive neuromodulation in the management COVID-19 and related disorders. Results: Non-invasive neuromodulation may manage disorders associated with COVID-19 through four pathways: (1) Direct infection mitigation through the stimulation of regions involved in the regulation of systemic anti-inflammatory responses and/or autonomic responses and prevention of neuroinflammation and recovery of respiration; (2) Amelioration of COVID-19 symptoms of musculoskeletal pain and systemic fatigue; (3) Augmenting cognitive and physical rehabilitation following critical illness; and (4) Treating outbreak-related mental distress including neurological and psychiatric disorders exacerbated by surrounding psychosocial stressors related to COVID-19. The selection of the appropriate techniques will depend on the identified target treatment pathway. Conclusion: COVID-19 infection results in a myriad of acute and chronic symptoms, both directly associated with respiratory distress (e.g., rehabilitation) or of yet-to-be-determined etiology (e.g., fatigue). Non-invasive neuromodulation is a toolbox of techniques that based on targeted pathways and empirical evidence (largely in non-COVID-19 patients) can be investigated in the management of patients with COVID-19.

Transcranial Direct Current Stimulation in Patients with Anxiety: Current Perspectives

Anxiety is one of the most prevalent and debilitating psychiatric conditions worldwide. Pharmaco- and psycho-therapies have been employed in the treatment of human anxiety to date. Yet, either alone or in combination, unsatisfactory patient outcomes are prevalent, resulting in a considerable number of people whose symptoms fail to respond to conventional therapies with symptoms remaining after intervention. The demand for new therapies has given birth to several noninvasive brain stimulation techniques. Transcranial direct current stimulation (tDCS) has arisen as a promising tool and has been proven to be safe and well tolerated for the treatment of many diseases, including chronic pain, depression, and anxiety. Here, reports of the use of tDCS in anxiety disorders in human patients were reviewed and summarized. A literature search was conducted in mid-2019, to identify clinical studies that evaluated the use of tDCS for the treatment of anxiety behavior. The PubMed, Web of Science, and Scielo and PsycInfo databases were explored using the following descriptors: "anxiety", "anxious behavior", "tDCS", and "transcranial direct current stimulation". Among the selected articles, considerable variability in the type of tDCS treatment applied in interventions was observed. Evidence shows that tDCS may be more effective when used in combination with drugs and cognitive behavioral therapies; however future large-scale clinical trials are recommended to better clarify the real effects of this intervention alone, or in combination with others.