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CompletedNCT04672122Updated Jun 22, 2022

The Effects of Cathodal tDCS on Muscle Strength in Healthy Adults

An interventional study of Transcranial direct current stimulation in Healthy Participants, sponsored by Mahidol University. Completed at 1 site in Thailand. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2022-06-22.

Sponsored by Mahidol University · Not applicable, Interventional, and Other

Phase
Not applicable
Study type
Interventional
Enrollment
48
Allocation
Randomized
Ages
18 Years to 60 Years
Sex
All
01

Study summary

To investigate the effects of different intensity of cathodal tDCS on muscle strength in healthy adults.

Read the detailed description

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that can modulate cortical excitability. In 2000, Nitsche and Paulus reported the polarity-dependent effect of tDCS in humans, i.e., anodal tDCS facilitates cortical excitability while cathodal tDCS decreases it. (Nitsche \& Paulus, 2000). TDCS studies have been replicated by many researchers and reported similar effects of tDCS in humans when using anodal and cathodal tDCS with an intensity of 1 mA. The linear effect of tDCS also has been reported by various studies, i.e., when increase intensity, the polarity-dependent effect of tDCS also enhances. However, conflicting results of cathodal tDCS efficacy have been reported.

Cortical excitability has been used to represent the efficacy of tDCS on neuroplasticity. The linear effect of cathodal tDCS on cortical excitability have been reported by researchers when using intensities at 1, 2, and 3 mA stimulated at the primary motor cortex in healthy participants (Batsikadze et al., 2013; Jamil et al., 2017; Kuo et al., 2013; Mosayebi Samani et al., 2019; Nitsche et al., 2003). Nevertheless, some studies showed the non-linear effects of cathodal tDCS (i.e., when increases intensity, cathodal tDCS enhances the cortical excitability) when using intensities at 1.5 and 2 mA in healthy participants (Batsikadze et al., 2013; Jamil et al., 2017; Mosayebi Samani et al., 2019). Hence, cathodal tDCS efficacy on cortical excitability is still controversy.

Muscle performance is an outcome that represents clinical change induced by tDCS. Previous studies reported the tendency of cathodal tDCS efficacy in decreasing muscle performance of both upper and lower extremities in healthy participants (Cogiamanian et al., 2007; Tanaka et al., 2009). However, previous studies used a single intensity of tDCS in each study. Hence, there was no direct comparison between different intensities of cathodal tDCS on muscle performance in healthy participants.

In our study, we aim to investigate the effect of different intensities of cathodal tDCS on muscle strength in healthy participants.

02

Conditions studied

  • Healthy Participants
03

In context

Lead sponsor

Mahidol University is the lead sponsor of 730 studies on the registry; 118 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 60 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  1. Male and female healthy adults
  2. Age range between 18 - 60 years old
  3. Right-handed dominant identified by the Edinburg Handedness Inventory
  4. No recent muscle injuries of both limbs for a past 6-months

Exclusion criteria

Exclusion Criteria:

  1. Consumed caffeine within 24 hours prior the experiment
  2. History of neurological symptoms i.e. seizures, weakness, loss of sensation or unclear history of pass illness
  3. Presence of metal implantation, intracranial shunt, cochlear implantation or cardiac pacemakers
  4. Presence of opened wound or infectious wound around scalp
  5. Presence of pain in evaluating muscle groups
  6. History of surgery in evaluating limbs
05

Study design

Phase
Not applicable
Primary purpose
Other
Allocation
Randomized
Intervention model
Factorial assignment
Masking
Double (Participant, Outcomes assessor)
Enrollment
48 participants (actual)

Study arms

  • Sham comparator
    Sham tDCS

    Sham transcranial direct current stimulation (tDCS) will be applied for 20 mins. Cathode on the primary motor area (M1) and Anode on the supraorbital area of contralateral side. Current intensity will be at 2 mA (sham mode). The scope of intervention is to investigate effect of sham tDCS on muscle strength.

    Device: Transcranial direct current stimulation

  • Experimental
    Cathodal-tDCS 1 mA

    Cathodal transcranial direct current stimulation (tDCS) will be applied for 20 mins. Cathode on the primary motor area (M1) and Anode on the supraorbital area of contralateral side. Current intensity is fixed at 1 mA and current will flow continuously. The scope of intervention is to investigate effect of cathodal tDCS on muscle strength.

    Device: Transcranial direct current stimulation

  • Experimental
    Cathodal-tDCS 1.5 mA

    Cathodal transcranial direct current stimulation (tDCS) will be applied for 20 mins. Cathode on the primary motor area (M1) and Anode on the supraorbital area of contralateral side. Current intensity is fixed at 1.5 mA and current will flow continuously. The scope of intervention is to investigate effect of cathodal tDCS on muscle strength.

    Device: Transcranial direct current stimulation

  • Experimental
    Cathodal-tDCS 2 mA

    Cathodal transcranial direct current stimulation (tDCS) will be applied for 20 mins. Cathode on the primary motor area (M1) and Anode on the supraorbital area of contralateral side. Current intensity is fixed at 2 mA and current will flow continuously. The scope of intervention is to investigate effect of cathodal tDCS on muscle strength.

    Device: Transcranial direct current stimulation

Interventions

  • DeviceTranscranial direct current stimulation

    Cathodal tDCS will be applied for 20 mins.

06

What researchers measure

Primary outcomes

  1. Change from baseline muscle strength after tDCS

    Muscle strength will be measured in Newton by using a hand-held dynamometer.

    Time frame: Baseline (Pretest) and 40 minutes ( posttest)

07

Study locations

1 site
  • Faculty of Physical Therapy, Mahidol University
    Salaya, Nakhon Pathom 73170, Thailand
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jun 22, 2022, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT04672122
Lead sponsor
Mahidol University
Responsible party
Sponsor
First posted
Dec 17, 2020
Start date
Nov 16, 2020
Primary completion
Mar 31, 2022
Completion
Mar 31, 2022
Last update
Jun 22, 2022

Study contacts

Wanalee Klomjai, PhD
study director · MU

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Jun 2022. You cannot join it, but the record below documents what was studied.

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