Effects of Different Intensities of Bilateral-transcranial Direct Current Stimulation in Healthy Individuals

Mahidol University

Status: Completed

Conditions: Healthy

Treatments: Device: Bilateral-Transcranial direct current stimulation (bilateral-tDCS); Device: Sham bilateral-tDCS

Study type: Interventional

Funder types: Other

Identifiers

NCT05929014

MU-CIRB 2023/016.1601

Details and patient eligibility

About

This study will investigate the effects of 1 mA, 1.5 mA, and 2 mA of bilateral- tDCS on cortical activity and motor learning in healthy individuals

Full description

Transcranial direct current stimulation (tDCS) is one of the non-invasive brain stimulation (NIBS) techniques. It delivers weak direct current through the scalp via two electrodes. tDCS has been shown to modulate cortical excitability in polarity-specific effects; anodal increases cortical excitability, while cathodal decreases it. tDCS can be applied in two distinct montages: unilateral (an active electrode is applied over the cerebral cortex, while a reference electrode is applied over the contralateral orbit) and bilateral-tDCS (applying two electrodes simultaneously over both cerebral hemispheres). Many tDCS studies have been used as an add-on therapy in stroke patients which aimed to enhance motor re-learning after stroke. Anodal tDCS has been used to enhance cortical excitability in the lesioned hemisphere while cathodal tDCS is used to decrease it in the non-lesioned hemisphere and thus to rebalance the interhemispheric inhibition (IHI). However, there were recent studies reporting the reverse effect of cathodal-tDCS on cortical excitability at high doses. However, the effects of bilateral-tDCS among different doses on cortical excitability and on motor performance are still controversial.

The present study will be investigated the effects of different intensities of bilateral-tDCS on cortical activity and functional outcomes in healthy individuals. A single session of different intensities of bilateral-tDCS (i.e., 1 mA, 1.5 mA, 2 mA vs. sham) will be combined with serial reaction time task (SRTT) in healthy individuals. Cortical activity (i.e., brain symmetry index (BSI)) will be measured as a primary outcome. The reaction time of serial reaction time task will be served as the secondary outcome. Cortical activity will be evaluated before and after the intervention, while reaction time will be evaluated before, during, and after the intervention.

Enrollment: 20 patients

Sex: All

Ages: 18 to 29 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• 1. Age 18-29 years old
• 2. Righ-hand dominant according to the Edinburgh handedness inventory
• 3. No injury to both upper and lower limb for the past 6 months

Exclusion criteria

• 1. Presence of any neurological disorders
• 2. Presence of metal implantation, intracranial shunt, cochlear implantation, or cardiac pacemakers
• 3. Presence of opened wound or infectious wound around scalp
• 4. History of epilepsy or any neurological antecedent or unstable condition which can lead to seizure
• 5. Body mass index (BMI) > 30 kg/m2
• 6. Received hormonal treatment and/or drugs that increase sleepiness and affect movement control
• 7. Ischemic heart disease and peripheral vascular ischemia
• 8. Last stage of kidney disease and liver disease

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Triple Blind

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20 participants in 2 patient groups

Active bilateral-tDCS

Active Comparator group

Description:

Participants will be received different intensities which are 1 mA, 1.5 mA and 2 mA for 20 minutes during performed serial reaction time task. The tDCS will be set with bilateral montage which applied anodal electrode over left hemisphere and cathodal electrode over right hemisphere.

Treatment:

Device: Bilateral-Transcranial direct current stimulation (bilateral-tDCS)

Sham bilateral-tDCS

Sham Comparator group

Description:

Participants will be received sham of bilateral tDCS during performed serial reaction time task.

Treatment:

Device: Sham bilateral-tDCS