Effect of conventional transcranial direct current stimulation devices and electrode sizes on motor cortical excitability of the quadriceps muscle

2021 ◽  
pp. 1-13
Author(s):  
Adam Z. Gardi ◽  
Amanda K. Vogel ◽  
Aastha K. Dharia ◽  
Chandramouli Krishnan
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Excitability ◽  
Null Model ◽  
Interaction Effects ◽  
Anodal Tdcs ◽  
Electrode Size ◽  
Direct Current Stimulation ◽  
Motor Cortical Excitability ◽  
Motor Cortical

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.

Changes in motor cortical excitability in schizophrenia following transcranial direct current stimulation

2019 ◽  
Vol 90 ◽  
pp. 43-48 ◽  
Author(s):  
Pedro Caldana Gordon ◽  
Leandro da Costa Lane Valiengo ◽  
Vanessa Jesus Rodrigues de Paula ◽  
Ricardo Galhardoni ◽  
Ulf Ziemann ◽  
...  
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Excitability ◽  
Direct Current Stimulation ◽  
Motor Cortical Excitability ◽  
Motor Cortical

scholarly journals Effect of transcranial direct current stimulation on post-stroke fatigue

2021 ◽  
Author(s):  
William De Doncker ◽  
Sasha Ondobaka ◽  
Annapoorna Kuppuswamy
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Excitability ◽  
Secondary Outcome ◽  
Anodal Tdcs ◽  
Single Session ◽  
Direct Current Stimulation ◽  
Post Stroke ◽  
Perceived Effort

Abstract Background Fatigue is one of the most commonly reported symptoms post-stroke, which has a severe impact on the quality of life. Post-stroke fatigue is associated with reduced motor cortical excitability, specifically of the affected hemisphere. Objective The aim of this exploratory study was to assess whether fatigue symptoms can be reduced by increasing cortical excitability using anodal transcranial direct current stimulation (tDCS). Methods In this sham-controlled, double-blind intervention study, tDCS was applied bilaterally over the primary motor cortex in a single session in thirty stroke survivors with high severity of fatigue. A questionnaire-based measure of trait fatigue (primary outcome) was obtained before, after a week and 5 weeks post stimulation. Secondary outcome measures of state fatigue, motor cortex neurophysiology and perceived effort were also assessed pre, immediately post, a week and 5 weeks post stimulation. Results Anodal tDCS significantly improved fatigue symptoms a week after real stimulation when compared to sham stimulation. There was also a significant change in motor cortex neurophysiology of the affected hemisphere and perceived effort, a week after stimulation. The degree of improvement in fatigue was associated with baseline anxiety levels. Conclusion A single session of anodal tDCS improves fatigue symptoms with the effect lasting up to a week post stimulation. tDCS may therefore be a useful tool for managing fatigue symptoms post-stroke. Trial registration NCT04634864 Date of registration 17/11/2020–“retrospectively registered”.

scholarly journals Different Current Intensities of Anodal Transcranial Direct Current Stimulation Do Not Differentially Modulate Motor Cortex Plasticity

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Dawson J. Kidgell ◽  
Robin M. Daly ◽  
Kayleigh Young ◽  
Jarrod Lum ◽  
Gregory Tooley ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Excitability ◽  
Short Interval ◽  
Long Term Potentiation ◽  
Anodal Tdcs ◽  
Noninvasive Technique ◽  
Direct Current Stimulation ◽  
Intracortical Circuits

Transcranial direct current stimulation (tDCS) is a noninvasive technique that modulates the excitability of neurons within the motor cortex (M1). Although the aftereffects of anodal tDCS on modulating cortical excitability have been described, there is limited data describing the outcomes of different tDCS intensities on intracortical circuits. To further elucidate the mechanisms underlying the aftereffects of M1 excitability following anodal tDCS, we used transcranial magnetic stimulation (TMS) to examine the effect of different intensities on cortical excitability and short-interval intracortical inhibition (SICI). Using a randomized, counterbalanced, crossover design, with a one-week wash-out period, 14 participants (6 females and 8 males, 22–45 years) were exposed to 10 minutes of anodal tDCS at 0.8, 1.0, and 1.2 mA. TMS was used to measure M1 excitability and SICI of the contralateral wrist extensor muscle at baseline, immediately after and 15 and 30 minutes following cessation of anodal tDCS. Cortical excitability increased, whilst SICI was reduced at all time points following anodal tDCS. Interestingly, there were no differences between the three intensities of anodal tDCS on modulating cortical excitability or SICI. These results suggest that the aftereffect of anodal tDCS on facilitating cortical excitability is due to the modulation of synaptic mechanisms associated with long-term potentiation and is not influenced by different tDCS intensities.

scholarly journals Effect of transcranial direct current stimulation on post-stroke fatigue

2020 ◽  
Author(s):  
William De Doncker ◽  
Sasha Ondobaka ◽  
Annapoorna Kuppuswamy
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Excitability ◽  
Secondary Outcome ◽  
Anodal Tdcs ◽  
Single Session ◽  
Direct Current Stimulation ◽  
Post Stroke ◽  
Perceived Effort

AbstractBackgroundFatigue is one of the most commonly reported symptoms post-stroke, which has a severe impact on quality of life. Post-stroke fatigue is associated with reduced motor cortical excitability, specifically of the affected hemisphere.ObjectiveThe aim of this exploratory study was to assess whether fatigue symptoms can be reduced by increasing cortical excitability using anodal transcranial direct current stimulation (tDCS).MethodsIn this sham-controlled, double-blind intervention study, tDCS was applied bilaterally over the primary motor cortex in a single session in thirty stroke survivors with high severity of fatigue. A questionnaire-based measure of trait fatigue (primary outcome) was obtained before, after a week and a month post stimulation. Secondary outcome measures of state fatigue, motor cortex neurophysiology and perceived effort were also assessed pre, immediately post, a week and a month post stimulation.ResultsAnodal tDCS significantly improved fatigue symptoms a week after real stimulation when compared to sham stimulation. There was also a significant change in motor cortex neurophysiology of the affected hemisphere and perceived effort, a week after stimulation. The degree of improvement in fatigue was associated with baseline anxiety levels.ConclusionA single session of anodal tDCS improves fatigue symptoms with the effect lasting up to a week post stimulation. tDCS may therefore be a useful tool for managing fatigue symptoms post-stroke.

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