Sham tDCS Group Research Articles

Effect of Self-administered Transcranial Direct Stimulation in Patients with Major Depressive Disorder: A Randomized, Single-blinded Clinical Trial.

ObjectiveIn numerous studies that have addressed transcranial direct current stimulation (tDCS) devices, participants visit the hospital regularly and undergo stimulation directed by health professionals. This method has the advantage of being able to deliver accurate stimuli in a controlled environment, but it does not adopt the merits of tDCS portability and applicability. Thus, it may be necessary to investigate how self-administered tDCS treatment at home affects depression-related symptoms.MethodsIn this randomized, single-blinded clinical trial, 58 patients with major depressive disorder were assigned to active and sham tDCS stimulation groups, and treatment responses were evaluated biweekly over six weeks. Both active and sham tDCS treatment group were treated with escitalopram. All participants were instructed the protocol and usage of at-home tDCS device, and self-administered tDCS treatment at their home.ResultsThe beck-depression inventory score decreased significantly as treatment progressed, and the degree of symptom improvement was significantly higher in the active group than in the sham tDCS group. There were no significant differences between the two groups in other indices, including the Hamilton Depression Scale.ConclusionThese results suggest that patient-administered tDCS treatment might be effective in improving subjective symptoms of depression.

Repetitive Transcranial Magnetic Stimulation and Transcranial Direct Current Stimulation as Treatment of Poststroke Depression: A Systematic Review and Meta-Analysis.

Previous studies showed that the application of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) during stroke rehabilitation improve the depression symptoms in poststroke depression (PSD). However, some studies showed inconsistent results. The study was designed to make a meta-analysis to evaluate the effect of noninvasive brain stimulation (tDCS and rTMS) on PSD. Articles published before July 2021 were searched in databases: PubMed, Web of Science, and Google Scholar. STATA 12.0 software was utilized to make meta-analysis. We extracted or calculated mean values and SD of reduction or increase rate of depression-related scales. Standardized mean difference (SMD) and 95% confidence intervals (CIs) were calculated as effect size. The study showed increased immediate and long-term improvement in depression in rTMS group compared with sham rTMS group after treatment with random-effects models (immediate: SMD=4.92, 95% CI=2.69-7.15, I2 =95.2%, P -value for Q test <0.001; long term: SMD=7.21, 95% CI=3.50-10.92, I2 =93.9%, P -value for Q test <0.001). Meta-analysis showed increased substantially immediate improvement in depression in tDCS group compared with sham tDCS group with a random effect model (SMD=5.30, 95% CI=1.30-9.30, I2 =97.3%, P- value for Q test <0.001). rTMS and tDCS were demonstrated to be effective and safe treatment techniques for PSD. More large-scale studies were essential to explore the effect of rTMS with different frequencies and tDCS on PSD.

Neurophysiological and behavioral effects of multisession prefrontal tDCS and concurrent cognitive remediation training in patients with autism spectrum disorder (ASD): A double-blind, randomized controlled fNIRS study

BackgroundThe clinical effects and neurophysiological mechanisms of prefrontal tDCS and concurrent cognitive remediation training in individuals with autism spectrum disorder (ASD) remain unclear. ObjectiveThis two-armed, double-blind, randomized, sham-controlled trial aimed to investigate the beneficial effects of tDCS combined with concurrent cognitive remediation training on adolescents and young adults with ASD. MethodsParticipants were randomly assigned to either active or sham tDCS groups and received 1.5 mA prefrontal tDCS with left dorsolateral prefrontal cortex (dlPFC) cathode placement and right supraorbital region anode placement for 20 minutes over two consecutive weeks. tDCS was delivered concurrently with a computerized cognitive remediation training program. Social functioning and its underlying cognitive processes, as well as prefrontal resting-state functional connectivity (rsFC), were measured. ResultsThe results from 41 participants indicated that multisession prefrontal tDCS, compared to sham tDCS, significantly enhanced the social functioning of ASD individuals [F(1,39) = 4.75, p = .035, ηp2 = 0.11]. This improvement was associated with enhanced emotion recognition [F(1,39) = 8.34, p = .006, ηp2 = 0.18] and cognitive flexibility [F(1,39) = 4.91, p = .033, ηp2 = 0.11]. Specifically, this tDCS protocol optimized information processing efficiency [F(1,39) = 4.43, p = .042, ηp2 = 0.10], and the optimization showed a trend to be associated with enhanced rsFC in the right medial prefrontal cortex (ρ = 0.339, pFDR = .083). ConclusionMultisession tDCS with left dlPFC cathode placement and right supraorbital region anode placement paired with concurrent cognitive remediation training promoted social functioning in individuals with ASD. This appeared to be associated with the enhancement of the functional connectivity of the right medial PFC, a major hub for flexible social information processing, allowing these individuals to process information more efficiently in response to different social situations. Trial registrationClinicalTrials.gov (ID: NCT03814083)

Transcranial Direct Current Stimulation on Different Targets to Modulate Cortical Activity and Dual-Task Walking in Individuals With Parkinson's Disease: A Double Blinded Randomized Controlled Trial.

BackgroundTranscranial direct current stimulation (tDCS) is a non-invasive brain stimulation to modulate cortical activity for improving motor function. However, the information of tDCS stimulation on different brain regions for dual-task walking and cortical modulation in Parkinson’s disease (PD) has not yet been compared.ObjectiveThe objective of this study was to investigate the effects of different tDCS targets on dual-task gait performance and cortical activity in patients with PD.MethodsA total of 36 participants were randomly assigned to primary motor cortex (M1) tDCS, dorsal lateral prefrontal cortex (DLPFC) tDCS, cerebellum tDCS, or Sham tDCS group. Each group received 20 min of tDCS stimulation, except for the Sham group. Gait performance was measured by the GAITRite system during dual-task walking and single walking. Corticomotor activity of the tibialis anterior (TA) was measured using transcranial magnetic stimulation (TMS). The functional mobility was assessed using the timed up and go (TUG) test.ResultsAll participants showed no significant differences in baseline data. Following the one session of tDCS intervention, M1 (p = 0.048), DLPFC (p < 0.001), and cerebellum (p = 0.001) tDCS groups demonstrated significant improvements in dual-task gait speed compared with a pretest. The time × group interaction [F(3, 32) = 5.125, p = 0.005] was detected in dual-task walking speed. The post hoc Tukey’s test showed that the differences in gait speed were between the Sham tDCS group and the DLPFC tDCS group (p = 0.03). Moreover, DLPFC tDCS also increased the silent period (SP) more than M1 tDCS (p = 0.006) and Sham tDCS (p = 0.002).ConclusionThe results indicate that DLPFC tDCS exerted the most beneficial effects on dual-task walking and cortical modulation in participants with PD.Clinical trial registration[http://www.thaiclinicaltrials.org/show/TCTR20200909005], Thai Clinical Trials Registry [TCTR20200909005].

Neuromodulation of somatosensory pain thresholds of the neck musculature using a novel transcranial direct current stimulation montage: a randomized double-blind, sham controlled study.

Anodal transcranial direct current stimulation (tDCS) of primary motor cortex (M1) and cathodal of the primary sensory cortex (S1) have previously shown to modulate the sensory thresholds when administered with the reference electrode located over the contralateral supraorbital area (SO). Combining the two stimulation paradigms into one with simultaneous stimulation of the two brain areas (M1+S1-tDCS) may result in a synergistic effect inducing a prominent neuromodulation, noticeable in the pain thresholds. The aim of this study is to assess the efficacy of the novel M1+S1-tDCS montage compared to sham-stimulation in modulating the pain thresholds in healthy adults. Thirty-nine (20 males) subjects were randomly assigned to either receiving 20min. active M1+S1-tDCS or sham tDCS in a double-blinded single session study. Thermal and mechanical pain thresholds were assessed before and after the intervention. There were no significant differences in the pain thresholds within either group, or between the M1+S1-tDCS group and the Sham-tDCS group (p>0.05), indicating that the intervention was ineffective in inducing a neuromodulation of the somatosensory system. Experimental investigations of novel tDCS electrode montages, that are scientifically based on existing studies or computational modelling, are essential to establish better tDCS protocols. Here simultaneous transcranial direct current stimulation of the primary motor cortex and primary sensory cortex showed no effect on the pain thresholds of the neck musculature in healthy subjects. This tDCS montage may have been ineffective due to how the electrical field reaches the targeted neurons, or may have been limited by the design of a single tDCS administration. The study adds to the existing literature of the studies investigating effects of new tDCS montages with the aim of establishing novel non-invasive brain stimulation interventions for chronic neck pain rehabilitation. North Denmark Region Committee on Health Research Ethics (VN-20180085) ClinicalTrials.gov (NCT04658485).

Evidence of Anti-Inflammatory Effect of Transcranial Direct Current Stimulation in a CFA-Induced Chronic Inflammatory Pain Model in Wistar Rats

Introduction: Given that chronic inflammatory pain is highly prevalent worldwide, it is important to study new techniques to treat or relieve this type of pain. The present study evaluated the effect of transcranial direct current stimulation (tDCS) in rats submitted to a chronic inflammatory model by nociceptive response, biomarker levels (brain-derived neurotrophic factor [BDNF] and interleukin [IL]-6 and IL-10), and by histological parameters. Methods: Sixty-day-old male Wistar rats were used in this study and randomized by weight into 6 major groups: total control, control + sham-tDCS, control + active tDCS, total CFA, CFA + sham-tDCS, and CFA + active tDCS. After inflammatory pain was established, the animals were submitted to the treatment protocol for 8 consecutive days, according to the experimental group. The nociceptive tests (von Frey and hot plate) were assessed, and euthanasia by decapitation occurred at day 8 after the end of tDCS treatment, and the blood serum and central nervous structures were collected for BDNF and IL measurements. All experiments and procedures were approved by the Institutional Committee for Animal Care and Use (UFPel #4538). Results: The tDCS treatment showed a complete reversal of the mechanical allodynia induced by the pain model 24 h and 8 days after the last tDCS session, and there was partial reversal of the thermal hyperalgesia at all time points. Serum BDNF levels were decreased in CFA + sham-tDCS and CFA + tDCS groups compared to the control + tDCS group. The control group submitted to tDCS exhibited an increase in serum IL-6 levels in relation to the other groups. In addition, there was a significant decrease in IL-10 striatum levels in control + tDCS, CFA, and CFA + sham-tDCS groups in relation to the control group, with a partial tDCS effect on the CFA pain model. Local histology demonstrated tDCS effects in decreasing lymphocytic infiltration and neovascularization and tissue regeneration in animals exposed to CFA. Conclusion: tDCS was able to reverse the mechanical allodynia and decrease thermal hyperalgesia and local inflammation in a chronic inflammatory pain model, with a modest effect on striatum IL-10 levels. As such, we suggest that analgesic tDCS mechanisms may be related to tissue repair by modulating the local inflammatory process.

Free Papers Compiled

Background:Alcohol Dependence is a chronic relapsing-remitting condition which has mostly shown moderate response to first line treatment options. tDCS has been explored as a potential therapeutic augmentation method in recent studies.Aims:To evaluate the effectiveness of tDCS in reducing craving in alcohol dependence syndrome.Methods:A randomized single-blind sham-controlled study was conducted at the CEIMH, ABVIMS and Dr. RML Hospital, New Delhi (1st November 2018 to 31st March 2020). Males (N=46) aged 18-50 years, diagnosed with alcohol dependence by ICD-10 were included in the study after screening for dependence by AUDIT. They were randomized to Groups A:- tDCS Group (n = 23) and B:- Sham tDCS Group (n = 23). A current of 2mA was applied for 20 minutes, twice a day for 5 days with a total 10 sessions on left (cathode) and right (anode) DLPFC. After the final session, VAS (Visual Analogue Scale for alcohol craving) and PACS (PENN Alcohol Craving Scale) were applied to compare the treatment effectiveness.Results:After 10 sessions both VAS and PENN scores (VAS score in Group A [1.17 (±1.11)] and Group B [4.78 (±2.88)] with P = 0.0001; and the PENN score in Group A [6.17 (±4.67)] and Group B [15.43 (±8.15)] with P =0.0002) were significantly reduced in the tDCS group.Conclusion:Study reported significant reduction in craving as reported by the VAS and PACS scores in patients treated with the tDCS. This stimulation protocol is a promising, non-expensive, add-on clinical tool that can help reduce alcohol craving in persons with alcohol dependence syndrome.

Effects of Non-Invasive Brain Stimulation on Alzheimer's Disease.

Previous meta-analyses did not explore the immediate and long-term effect of non-invasive brain stimulation (NIBS) on different cognitive domains in Alzheimer's disease (AD). The meta-analysis aimed to assess the therapy effect of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) on different cognitive domains in AD in randomized controlled trials (RCTs). Studies published before December 2021 and exploring therapy effect of rTMS, tDCS on different cognitive domains in AD were searched in the following databases: PubMed and Web of Science. We used STATA 12.0 software to compute the standard mean difference (SMD) and a 95% confidence interval (CI). The present study included 16 articles (including 372 AD patients treated with rTMS and 310 treated with sham rTMS) for rTMS and 11 articles (including 152 AD patients treated with tDCS and 134 treated with sham tDCS) for tDCS. The present study showed better immediate and long-term general cognitive function increase effects in AD given rTMS, compared to those given sham rTMS with random effects models (immediate effect: SMD = 2.07, 95% CI = 0.37 to 3.77, I2 = 97.8%, p < 0.001; long-term effect: SMD = 5.04, 95% CI = 2.25 to 7.84, I2 = 97.8%, p < 0.001). The present study showed no significant immediate and long-term effects of rTMS on attention, executive, language and memory functions. In addition, the present study showed no significant difference in immediate or long-term effects of tDCS on general cognitive function, attention, language or memory functions between tDCS group and sham tDCS group. RTMS was an effective treatment technique for general cognitive function in AD, whereas tDCS showed no significant therapy effect on cognitive function in AD. More large-scale studies were essential to explore the effect of NIBS on various cognitive function in AD.

Symposium

Objective:Neuromodulatory interventions like transcranial direct current stimulation (tDCS) is an emerging and potential therapeutic strategy to help in reducing craving and relapse prevention in patients of alcohol dependence syndrome (1–4). The potential target for alcohol dependence is the dorsolateral pre-frontal cortex (dlPFC) as frontal dysfunction is a hallmark of alcoholism, even in alcohol dependence subjects with no major clinical and global cognitive deficits (5). In this context, this study was designed to explore the effect of tDCS treatment on craving and relapse prevention and its correlation to dorsolateral prefrontal cortex (DLPFC) activation in alcohol dependent patients.Methodology:This study was a double blinded randomized sham control trial, conducted at National Institute of Mental Health and Neurosciences, Bangalore after approval by the Institute Ethics Committee. Twenty-four patients of alcohol dependence syndrome were recruited after informed consent. After detoxification patients underwent baseline fMRI scans. Followed by tDCS with intensity of 2mA and duration of 20 minutes per day was administered for 5 consecutive days with cathode over left dorsolateral prefrontal cortex (DLPFC) and anode over right DLPFC. On the 5th day post fMRI scans were repeated. Both investigator and subjects remained blind throughout the study period. During scans patients were exposed to visual alcohol cues using VICE (visual image- Induced craving for ethanol) paradigm. Pre- treatment and post-treatment scans were analysed using SPM-12 software.Results:At the beginning of the study, 24 subjects were selected but 2 subjects dropped out before post fMRI scan. The baseline comparison of socio-demographic and clinical variables found to have no differences among both groups.fMRI results: At baseline, the true and sham tDCS groups had comparable BOLD activation patterns and there were no between-group differences in activation pattern noted for alcohol vs. neutral cues contrast. Following 5 sessions of tDCS, there is significantly increased activation observed in true tDCS group, from Pre- to Post- treatment scans. Brain activity at DLPFC (Post-Pre) was positively associated with time to first alcohol lapse (p=0.048, Spearman’s rho =0.426). This suggests that greater the increase in brain activity at DLPFC after treatment with bilateral repetitive tDCS longer was the time to first lapse. Conclusion:This study has shown bilateral repetitive transcranial direct current stimulation in alcohol dependent subjects, activates dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) along with increase in the connectivity strength between medial frontal gyrus (MFG) and sub cortical reward centre (NAc), which facilitated abstinence from alcohol. So from this study we better understood the mechanism of tDCS in preventing relapse to alcohol by activation of dorsolateral prefrontal cortex and anterior cingulated cortex. Though the fMRI results were statistically significant for relapse and DLPFC activation, but it would be difficult to establish the clinical significance of the improvement in craving in the background of small sample size. Hence further studies with larger sample size are required in near future. Referrences: 1. Klauss J, Penido Pinheiro LC, Silva Merlo BL, Correia Santos GDA, Fregni F, Nitsche MA, et al. A randomized controlled trial of targeted prefrontal cortex modulation with tDCS in patients with alcohol dependence. Int J Neuropsychopharmacol. 2014;17(11):1793–803.2. Boggio PS, Sultani N, Fecteau S, Merabet L, Mecca T, Pascual-Leone A, et al. Prefrontal cortex modulation using transcranial DC stimulation reduces alcohol craving: A double-blind, sham-controlled study. Drug Alcohol Depend. 2008;92(1–3):55–60.3. Nakamura-Palacios EM, Lopes IBC, Souza RA, Klauss J, Batista EK, Conti CL, et al. Ventral medial prefrontal cortex (vmPFC) as a target of the dorsolateral prefrontal modulation by transcranial direct current stimulation (tDCS) in drug addiction. J Neural Transm. 2016;123(10):1179–94.4. da Silva MC, Conti CL, Klauss J, Alves LG, do Nascimento Cavalcante HM, Fregni F, et al. Behavioral effects of transcranial Direct Current Stimulation (tDCS) induced dorsolateral prefrontal cortex plasticity in alcohol dependence. J Physiol. 2013;107(6):493–502.5. Nakamura-Palacios EM, Souza RSM, Zago-Gomes MP, de Melo AMF, Braga FS, Kubo TTA, et al. Gray Matter Volume in Left Rostral Middle Frontal and Left Cerebellar Cortices Predicts Frontal Executive Performance in Alcoholic Subjects. Alcohol Clin Exp Res [Internet]. 2014 Apr 1 ;38(4):1126–33. Available from: http://doi.wiley.com/10.1111/ acer.12308

Effects of transcranial direct current stimulation on physical and mental health in older adults with chronic musculoskeletal pain: a randomized controlled trial.

We investigated the effects of transcranial direct current stimulation (tDCS) combined with physical therapy (PT) on pain levels, physical activity levels, quality of life, and depression in older adults with chronic musculoskeletal pain. Twenty-five older adults (9 males and 16 females), aged between 66 and 86years (active group 77.2 ± 3.9; sham group 76.6 ± 6.2), volunteers were randomly allocated in the active (active tDCS + PT) and sham groups (sham tDCS + PT), and received the intervention three times per week for 8weeks. Pain level, physical activity level, depression state, and quality of life were assessed based on the Visual Analog Scale (VAS), Physical Activity Scale for the Elderly (PASE), Beck Depression Inventory (BDI) scale, and Short-Form 36 Health Survey Questionnaire (SF-36), respectively. Measurements were conducted four times: at baseline, mid-intervention, post-intervention, and 1-month follow-up. As a result, at 8weeks, the active group yielded greater improvements in VAS, BDI, and SF-36 scores than the sham tDCS group. At follow-up, the tDCS group led to a greater improvement in VAS, PASE, and SF-36 scores compared to sham tDCS group (p < 0.05). Our results suggest a beneficial effect of tDCS combined with PT in older adults with chronic musculoskeletal pain in the reduction of pain sensation, increment of physical activity level, increment of the quality of life, and reduction of depression incidents. This opens the possibility the possibility of using tDCS as a regular treatment for this population's physical and mental health.

The effect of transcranial direct current stimulation (tDCS) combined with cognitive training on EEG spectral power in adolescent boys with ADHD: A double-blind, randomized, sham-controlled trial.

Transcranial direct current stimulation (tDCS) is a possible alternative to psychostimulants in Attention-Deficit/Hyperactivity Disorder (ADHD), but its mechanisms of action in children and adolescents with ADHD are poorly understood. We conducted the first 15-session, sham-controlled study of anodal tDCS over right inferior frontal cortex (rIFC) combined with cognitive training (CT) in 50 children/adolescents with ADHD. We investigated the mechanisms of action on resting and Go/No-Go Task-based QEEG measures in a subgroup of 23 participants with ADHD (n, sham = 10; anodal tDCS = 13). We failed to find a significant sham versus anodal tDCS group differences in QEEG spectral power during rest and Go/No-Go Task performance, a correlation between QEEG and Go/No-Go Task performance, and changes in clinical and cognitive measures. These findings extend the non-significant clinical and cognitive effects in our sample of 50 children/adolescents with ADHD. Given that the subgroup of 23 participants would have been underpowered, the interpretation of our findings is limited and should be used as a foundation for future investigations. Larger, adequately powered randomized controlled trials should explore different protocols titrated to the individual and using comprehensive measures to assess cognitive, clinical, and neural effects of tDCS and its underlying mechanisms of action in ADHD.

Transcranial Direct Current Stimulation Provides no Additional Benefit to Improvements in Self-Reported Craving Following Mindfulness-Based Relapse Prevention.

Mindfulness-Based Relapse Prevention (MBRP) and transcranial direct current stimulation (tDCS) have each demonstrated efficacy in improving outcomes in those with alcohol use disorder (AUD), however a recent study that combined MBRP with tDCS found tDCS provided no additional benefit to MBRP for AUD. Differences in treatment adherence between active versus sham tDCS groups may have contributed to this result. The current study examined whether treatment adherence interacted with tDCS condition in predicting post-treatment mindfulness and craving. This study was a secondary data analysis from a randomized sham-controlled trial comparing MBRP paired with tDCS. Linear regression analyses were conducted examining the interaction between tDCS condition and two measures of treatment adherence (i.e., number of groups attended, number of tDCS administrations) on post-treatment mindfulness and craving. There was no effect of treatment adherence by tDCS condition in predicting mindfulness, however the interaction between treatment adherence and tDCS condition significantly predicted post-treatment craving. There was a significant negative association between treatment adherence and post-treatment craving in the sham group, but there was no association in the active tDCS group. MBRP coupled with sham stimulation led to significant reductions in self-reported craving when patients attended more sessions and received a greater number of sham tDCS administrations, while no relationship was observed between treatment adherence and craving among those who received active tDCS. This result provides tentative evidence that, rather than improve the effects of MBRP on craving, this active tDCS protocol provides no additional benefit to MBRP in reducing craving. This study was registered with clinicaltrials.gov (NCT02861807).

Effects of transcranial direct current stimulation associated with an aerobic exercise bout on blood pressure and autonomic modulation of hypertensive patients: A pilot randomized clinical trial.

The objective of this article was to evaluate the effects of an aerobic exercise bout associated with a single session of anodal transcranial direct current stimulation (tDCS) over the left temporal lobe on blood pressure (BP) and heart rate variability (HRV) in hypertensive people. After met the inclusion criteria, twenty hypertensive people were randomized to active-tDCS or sham-tDCS group. Initially, they provided their sociodemographic data, a blood sample, and went through an evaluation of the cardiorespiratory performance. Then, a single session of tDCS with an intensity of 2mA over the left lobe during 20min was carried out. After tDCS, it was performed a session of moderate-intensity aerobic exercise during 40min. BP during 24h and HRV measurements were performed before (baseline) and after the intervention. Systolic BP during sleep time decreased in the active-tDCS group (p=0.008). Diastolic BP showed a significant decrease 3h after the intervention in the active-tDCS group (p=0.01). An intragroup comparison showed a significant decrease in systolic BP 3h after intervention only for the active-tDCS group (p=0.04). Besides, there was a trend toward a difference in wake for diastolic BP for active-tDCS (p=0.07). Lastly, there were no changes in the HRV for both groups. It is suggested that anodal tDCS associated with moderate-intensity aerobic exercise can decrease systolic and diastolic BP of hypertensive people during sleep time and 3h after the intervention.

The effect of high-definition transcranial direct current stimulation on pain processing in a healthy population: A single-blinded crossover controlled study

Transcranial direct current stimulation (tDCS) is increasingly used in pain treatment. tDCS targeting both primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) may modulate the descending pain inhibitory system, however, it remains controversial regarding the optimal stimulation region for pain modulation. Therefore, this study aimed to explore the effects of high-definition anodic stimulation of M1 and DLPFC on conditioned pain modulation (CPM) and pain thresholds and establish a preferred stimulation setting. Twenty-six healthy adults were randomly assigned to M1-tDCS, DLPFC-tDCS, or sham-tDCS groups. During the three sessions, each participant received an active or sham stimulation of 2 mA for 20 min, with at least 3 days’ interval between sessions. Quantitative sensory tests were performed to obtain pressure pain threshold (PPT), cold pain threshold (CPT), and CPM before and after the tDCS intervention. Only M1-tDCS significantly increased CPM in healthy individuals compared with sham control (P = 0.004). No statistically significant difference was found in PPT and CPT between tDCS vs. sham control (P > 0.05). Our findings further support the important role of M1 as a target in pain regulation. Further large-scale, multicenter studies in chronic pain populations are needed to validate the alterations of distinct target brain regions related to pain and thus for an optimal target stimulation strategy in pain management.

Effect of non-invasive brain stimulation on lower limb function in patients after stroke: A PRISMA-compliant systematic review and meta-analysis

Background: In recent years, it is reported that non-invasive brain stimulation [including transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS)] could improve lower limb function in patients after stroke. However, some studies showed no effect. In the present study, we aimed to make a meta-analysis to assess effect of non-invasive brain stimulation on lower limb function in patients after stroke. Methods: Studies exploring the effect of tDCS or rTMS on lower limb function in patients after stroke were searched on the PubMed, Web of Science, EMBASE, Medline, Google Scholar before March 2021. Meta-analysis was made to summarize results of these studies. Results: The present study showed significantly better walking speed, mobility and muscle strength increase effect in tDCS group compared to sham tDCS group [walking speed: standard mean difference (SMD) = 1.14, 95% CI = 0.48 to 1.80, I2 = 74.0%, p value for Q test &lt; 0.001; mobility: SMD = 0.79, 95% CI = 0.21 to 1.36, I2 = 53.8%, p value for Q test = 0.043; muscle strength: SMD = 2.79, 95% CI = 0.61 to 4.98, I2 = 93.9%, p value for Q test &lt; 0.001]. In addition, meta-analysis showed significantly better walking speed, balance and motor function increase effect in rTMS group compared to sham rTMS group [walking speed: SMD = 3.31, 95% CI = 1.38 to 5.24, I2 = 92.1%, p value for Q test &lt; 0.001; balance: SMD = 3.54, 95% CI = 1.45 to 5.63, I2 = 95.4%, p value for Q test &lt; 0.001; motor function: SMD = 1.65, 95% CI = 0.53 to 2.76, I2 = 90.3%, p value for Q test &lt; 0.001]. Conclusions: This meta-analysis suggested that non-invasive brain stimulation improved lower limb function in patients after stroke. More large scale, blinded RCTs were necessary to confirm the effect of rTMS and tDCS on lower limb function in patients after stroke.

Individual Differences Modulate the Effects of tDCS on Reading in Children and Adolescents with Dyslexia

ABSTRACT Emerging evidence suggests that the combination of transcranial direct current stimulation (tDCS) and reading training may provide promising benefits for dyslexia; however, the clinical effects and the role of individual differences in tDCS outcomes for dyslexia remain unclear. To this end, the present study investigated the effects of tDCS on clinically relevant reading measures and examined factors (i.e. reading at baseline, age, and intelligence quotient [IQ]) that may contribute to improvements following tDCS treatment. Our results showed that, in terms of word reading fluency, the percentage of responders in the active tDCS group was higher than that in the sham tDCS group. Linear mixed effects models showed that the effect of tDCS and reading training tasks on word reading fluency depended on reading at baseline with age and IQ. Thus, the present study provides research-based selection criteria for potential responders to tDCS and encourages tailored intervention based on individual characteristics.

Rekindling Action Language: A Neuromodulatory Study on Parkinson's Disease Patients.

Impairments of action semantics (a cognitive domain that critically engages motor brain networks) are pervasive in early Parkinson’s disease (PD). However, no study has examined whether action semantic skills in persons with this disease can be influenced by non-invasive neuromodulation. Here, we recruited 22 PD patients and performed a five-day randomized, blinded, sham-controlled study to assess whether anodal transcranial direct current stimulation (atDCS) over the primary motor cortex, combined with cognitive training, can boost action–concept processing. On day 1, participants completed a picture–word association (PWA) task involving action-verb and object-noun conditions. They were then randomly assigned to either an atDCS (n = 11, 2 mA for 20 m) or a sham tDCS (n = 11, 2 mA for 30 s) group and performed an online PWA practice over three days. On day 5, they repeated the initial protocol. Relative to sham tDCS, the atDCS group exhibited faster reaction times for action (as opposed to object) concepts in the post-stimulation test. This result was exclusive to the atDCS group and held irrespective of the subjects’ cognitive, executive, and motor skills, further attesting to its specificity. Our findings suggest that action-concept deficits in PD are distinctively grounded in motor networks and might be countered by direct neuromodulation of such circuits. Moreover, they provide new evidence for neurosemantic models and inform a thriving agenda in the embodied cognition framework.

Effect of Anodic Transcranial Direct Current Stimulation Combined With Speech Language Therapy on Nonfluent Poststroke Aphasia

Transcranial direct current stimulation (tDCS) facilitates or inhibits spontaneous neuronal activity by low-intensity current. In this study, we evaluated the effects of tDCS and sham stimulation combined with speech language therapy (SLT) on nonfluent poststroke aphasia (PSA) patients. Patients with PSA were randomly divided into the anode tDCS (A-tDCS) group (n=8) and sham tDCS (S-tDCS) group (n=10). The anodes and cathodes were fixed over left inferior gyrus frontalis (L-IFG) and the deltoid muscle of the right shoulder. A-tDCS consisted of 2mA for 20 min, while S-tDCS current started at 2mA but automatically decreased to 0mA after 30 sec. Stimulation was concurrent with 30 min of SLT. Stimulation + SLT sessions occurred five times a week for four weeks. The Western Aphasia Battery (WAB) was given before treatment to obtain the baseline score and once more after all sessions were completed, and the Aphasia Quotient (AQ) was calculated. After tDCS treatment, the AQ mean(SD) in both groups was significantly higher than before treatment (p < 0.001) and the AQ of the A-tDCS group 72.99 (21.91) was significantly higher than that of the S-tDCS group 46.18 (19.29) (t=2.760, p < 0.05). Upon further analysis of the WAB subscores, except for comprehension, all other items were significantly higher in the A-tDCS group than in the S-tDCS group (p < 0.05). Our results suggest that left inferior gyrus frontalis anodic transcranial direct current stimulation is an effective adjuvant to conventional speech language therapy for patients with nonfluent PSA.

A double-blind randomized controlled trial combining cognitive training (CoRe) and neurostimulation (tDCS) in the early stages of cognitive impairment.

The prevalence of neurodegenerative diseases is expected to increase over the next years, therefore, new methods able to prevent and delay cognitive decline are needed. To evaluate the effectiveness of a combined treatment protocol associating a computerized cognitive training (CoRe) with anodal transcranial direct current stimulation (tDCS). In this randomized controlled trial, 33 patients in the early stage of cognitive impairment were assigned to the experimental group (CoRE + real tDCS) or control group (CoRE + sham tDCS). In each group, the intervention lasted 3 consecutive weeks (4 sessions/week). A neuropsychological assessment was administered at baseline (T0), post-intervention (T1) and 6-months later (T2). The CoRE + real tDCS group only improved in working memory and attention/processing speed at both T1 and T2. It reported a stable MMSE score at T2, while the CoRE + sham tDCS group worsened. Age, mood, and T0 MMSE score resulted to play a role in predicting treatment effects. Combined multi-domain interventions may contribute to preventing or delaying disease progression. Trial registration number (ClinicalTrials.gov): NCT04118686.

Effects of transcranial direct current stimulation on cognitive dysfunction in multiple sclerosis

BackgroundAround 40%–70% of patients with multiple sclerosis (MS) may experience cognitive impairments during the course of their disease with detrimental effects on social and occupational activities. Transcranial direct current stimulation (tDCS has been investigated in pain, fatigue, and mood disorders related to MS, but to date, few studies have examined effects of tDCS on cognitive performance in MS. ObjectiveThe current study aimed to investigate the effects of a multi-session tDCS protocol on cognitive performance and resting-state brain electrical activities in patients with MS. MethodsTwenty-four eligible MS patients were randomly assigned to real (anodal) or sham tDCS groups. Before and after 8 consecutive daily tDCS sessions over the left dorsolateral prefrontal cortex (DLPFC), patients’ cognitive performance was assessed using the Cambridge Brain Sciences-Cognitive Platform (CBS-CP). Cortical electrical activity was also evaluated using quantitative electroencephalography (QEEG) analysis at baseline and after the intervention. ResultsCompared to the sham condition, significant improvement in reasoning and executive functions of the patients in the real tDCS group was observed. Attention was also improved considerably but not statistically significantly following real tDCS. However, no significant changes in resting-state brain activities were observed after stimulation in either group. ConclusionAnodal tDCS over the left DLPFC appears to be a promising therapeutic option for cognitive dysfunction in patients with MS. Larger studies are required to confirm these findings and to investigate underlying neuronal mechanisms.