The Effect of Transcranial Direct Current Stimulation (tDCS) Electrode Size and Current Intensity on Motor Cortical Excitability: Evidence From Single and Repeated Sessions

2016 ◽  
Vol 9 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kerrie-Anne Ho ◽  
Janet L. Taylor ◽  
Taariq Chew ◽  
Verònica Gálvez ◽  
Angelo Alonzo ◽  
...  
2021 ◽  
pp. 1-13
Author(s):  
Adam Z. Gardi ◽  
Amanda K. Vogel ◽  
Aastha K. Dharia ◽  
Chandramouli Krishnan

Background: There is a growing concern among the scientific community that the effects of transcranial direct current stimulation (tDCS) are highly variable across studies. The use of different tDCS devices and electrode sizes may contribute to this variability; however, this issue has not been verified experimentally. Objective: To evaluate the effects of tDCS device and electrode size on quadriceps motor cortical excitability. Methods: The effect of tDCS device and electrode size on quadriceps motor cortical excitability was quantified across a range of TMS intensities using a novel evoked torque approach that has been previously shown to be highly reliable. In experiment 1, anodal tDCS-induced excitability changes were measured in twenty individuals using two devices (Empi and Soterix) on two separate days. In experiment 2, anodal tDCS-induced excitability changes were measured in thirty individuals divided into three groups based on the electrode size. A novel Bayesian approach was used in addition to the classical hypothesis testing during data analyses. Results: There were no significant main or interaction effects, indicating that cortical excitability did not differ between different tDCS devices or electrode sizes. The lack of pre-post time effect in both experiments indicated that cortical excitability was minimally affected by anodal tDCS. Bayesian analyses indicated that the null model was more favored than the main or the interaction effects model. Conclusions: Motor cortical excitability was not altered by anodal tDCS and did not differ by devices or electrode sizes used in the study. Future studies should examine if behavioral outcomes are different based on tDCS device or electrode size.


Author(s):  
Pedro Caldana Gordon ◽  
Leandro da Costa Lane Valiengo ◽  
Vanessa Jesus Rodrigues de Paula ◽  
Ricardo Galhardoni ◽  
Ulf Ziemann ◽  
...  

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Fateme Pol ◽  
Mohammad Ali Salehinejad ◽  
Hamzeh Baharlouei ◽  
Michael A. Nitsche

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.


2020 ◽  
Vol 41 (6) ◽  
pp. 1644-1666 ◽  
Author(s):  
Asif Jamil ◽  
Giorgi Batsikadze ◽  
Hsiao‐I. Kuo ◽  
Raf L. J. Meesen ◽  
Peter Dechent ◽  
...  

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