The neurobiology of prefrontal transcranial direct current stimulation (tDCS) in promoting brain plasticity: a systematic review and meta-analyses of human and rodent studies

2021 ◽  
Author(s):  
Melody M.Y. Chan ◽  
Sonata S.Y. Yau ◽  
Yvonne M.Y. Han
Keyword(s):  
Systematic Review ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Brain Plasticity ◽  
Direct Current Stimulation ◽  
Meta Analyses

scholarly journals Determining the effects of transcranial direct current stimulation on tinnitus and tinnitus-related outcomes: protocol for a systematic review

BMJ Open ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. e047191
Author(s):  
Bas Labree ◽  
Derek J Hoare ◽  
Lauren E Gascoyne ◽  
Magdalena Sereda
Keyword(s):  
Quality Of Life ◽  
Systematic Review ◽  
Adverse Effects ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Ethical Issues ◽  
Future Research ◽  
Direct Current Stimulation ◽  
Meta Analyses

IntroductionTinnitus is the awareness of a sound in the ear or head in the absence of an external source. It affects around 10%–15% of people. About 20% of people with tinnitus also experience symptoms such as depression or anxiety that negatively affect their life. Transcranial direct current stimulation (tDCS) is a technique involving constant low-intensity direct current delivered via electrodes on the head. It is postulated to modulate (suppress or enhance) neural activity in the region between electrodes. As such, it represents a potential treatment option for tinnitus, as well as comorbid depression or anxiety. This systematic review will estimate the effects of tDCS on outcomes relevant to tinnitus. In addition, it will determine whether there is any relationship between stimulation parameters (electrode montage, current intensity, and length and frequency of stimulation sessions) and the effect of tDCS on these outcomes.Methods and analysisElectronic searches for peer-reviewed journal articles will be performed in the Cochrane Register of Studies online (the Cochrane Ear, Nose and Throat Disorders Group Register and CENTRAL, current issue), PubMed, EMBASE, CINAHL, LILACS, KoreaMed, IndMed, PakMediNet, CNKI, AMED, PsycINFO, Web of Science, ClinicalTrials.gov, ICTRP and Google Scholar using the following search terms: transcranial Direct Current Stimulation OR tDCS AND tinnitus OR depression OR anxiety OR quality of life OR adverse effects OR neurophys*.Searches were not limited by date. Methods are reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P). Randomised controlled trials will be included if they report at least one of the following outcomes: tinnitus symptom severity, anxiety or depression as measured by relevant validated instruments. Where available, data on quality of life, adverse effects and neurophysiological changes will also be reviewed. In addition to an analysis of the effect of each parameter, an analysis will be performed to uncover any interactions between parameters. Where appropriate, meta‐analyses will be performed.Ethics and disseminationThis systematic review will make use of secondary data only. As no data will be obtained from participants directly, ethical approval has not been sought. No other ethical issues are foreseen. Findings will be submitted for peer-reviewed publication and presented at academic conferences. The results of this review will inform future research.PROSPERO registration numberCRD42020185567.

scholarly journals Can Transcranial Direct Current Stimulation Enhance Functionality in Older Adults? A Systematic Review

2021 ◽  
Vol 10 (13) ◽  
pp. 2981
Author(s):  
Andrés Pino-Esteban ◽  
Álvaro Megía-García ◽  
David Martín-Caro Álvarez ◽  
Hector Beltran-Alacreu ◽  
Juan Avendaño-Coy ◽  
...  
Keyword(s):  
Systematic Review ◽  
Older Adults ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Randomized Clinical Trials ◽  
Scientific Evidence ◽  
Healthy Older Adults ◽  
Sham Stimulation ◽  
Direct Current Stimulation ◽  
Potential Benefits

Transcranial direct current stimulation (tDCS) is a non-invasive, easy to administer, well-tolerated, and safe technique capable of affecting brain excitability, both at the cortical and cerebellum levels. However, its effectiveness has not been sufficiently assessed in all population segments or clinical applications. This systematic review aimed at compiling and summarizing the currently available scientific evidence about the effect of tDCS on functionality in older adults over 60 years of age. A search of databases was conducted to find randomized clinical trials that applied tDCS versus sham stimulation in the above-mentioned population. No limits were established in terms of date of publication. A total of 237 trials were found, of which 24 met the inclusion criteria. Finally, nine studies were analyzed, including 260 healthy subjects with average age between 61.0 and 85.8 years. Seven of the nine included studies reported superior improvements in functionality variables following the application of tDCS compared to sham stimulation. Anodal tDCS applied over the motor cortex may be an effective technique for improving balance and posture control in healthy older adults. However, further high-quality randomized controlled trials are required to determine the most effective protocols and to clarify potential benefits for older adults.

scholarly journals The effects of transcranial direct current stimulation on gait in patients with Parkinson’s disease: a systematic review

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Fateme Pol ◽  
Mohammad Ali Salehinejad ◽  
Hamzeh Baharlouei ◽  
Michael A. Nitsche
Keyword(s):  
Systematic Review ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Randomized Clinical Trials ◽  
Cortical Excitability ◽  
Experimental Studies ◽  
Gait Rehabilitation ◽  
Direct Current Stimulation

Abstract Background Gait problems are an important symptom in Parkinson’s disease (PD), a progressive neurodegenerative disease. Transcranial direct current stimulation (tDCS) is a neuromodulatory intervention that can modulate cortical excitability of the gait-related regions. Despite an increasing number of gait-related tDCS studies in PD, the efficacy of this technique for improving gait has not been systematically investigated yet. Here, we aimed to systematically explore the effects of tDCS on gait in PD, based on available experimental studies. Methods Using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach, PubMed, Web of Science, Scopus, and PEDro databases were searched for randomized clinical trials assessing the effect of tDCS on gait in patients with PD. Results Eighteen studies were included in this systematic review. Overall, tDCS targeting the motor cortex and supplementary motor area bilaterally seems to be promising for gait rehabilitation in PD. Studies of tDCS targeting the dorosolateral prefrontal cortex or cerebellum showed more heterogeneous results. More studies are needed to systematically compare the efficacy of different tDCS protocols, including protocols applying tDCS alone and/or in combination with conventional gait rehabilitation treatment in PD. Conclusions tDCS is a promising intervention approach to improving gait in PD. Anodal tDCS over the motor areas has shown a positive effect on gait, but stimulation of other areas is less promising. However, the heterogeneities of methods and results have made it difficult to draw firm conclusions. Therefore, systematic explorations of tDCS protocols are required to optimize the efficacy.

scholarly journals The effects of transcranial direct current stimulation on objective and subjective indexes of exercise performance: a systematic review and meta-analysis.

2018 ◽  
Author(s):  
Darias Holgado ◽  
Miguel A. Vadillo ◽  
Daniel Sanabria
Keyword(s):  
Systematic Review ◽  
Direct Current ◽  
Exercise Performance ◽  
Transcranial Direct Current Stimulation ◽  
Perceived Exertion ◽  
Effect Sizes ◽  
Electrode Placement ◽  
Current Evidence ◽  
Time To Exhaustion ◽  
Direct Current Stimulation

Objective: To examine the effectss of transcranial direct current stimulation (tDCS) on objective and subjective indexes of exercise performance.Design: Systematic review and meta-analysis.Data Sources: A systematic literature search of electronic databases (PubMed, Web of Science, Scopus, Google Scholar) and reference lists of included articles up to June 2018.Eligibility Criteria: Published articles in journals or in repositories with raw data available, randomized sham-controlled trial comparing anodal stimulation with a sham condition providing data on objective (e.g. time to exhaustion or time-trial performance) or subjective (e.g. rate of perceived exertion) indexes of exercise performance.Results: The initial search provided 420 articles of which 31 were assessed for eligibility. Finally, the analysis of effect sizes comprised 24 studies with 386 participants. The analysis indicated that anodal tDCS had a small but positive effect on performance g = 0.34, 95% CI [0.12, 0.52], z = 3.24, p = 0.0012. Effects were not significantly moderated by type of outcome, electrode placement, muscles involved, number of sessions, or intensity and duration of the stimulation. Importantly, the funnel plot showed that, overall, effect sizes tended to be larger in studies with lower sample size and high standard error. Summary: The results suggest that tDCS may have a positive impact on exercise performance. However, the effect is probably small and most likely biased by low quality studies and the selective publication of significant results. Therefore, the current evidence does not provide strong support to the conclusion that tDCS is an effective means to improve exercise performance.

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