The Effect of Transcranial Direct Current Stimulation on Motor Performance in Healthy Adults

Study Overview
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Brief Summary
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to investigate the effect of stimulation intensity on motor performance in healthy adults.

Detailed Description
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60 healthy subjects were randomly allocated to one of three groups: (a) 20-min of High-Definition transcranial direct current stimulation (HD-tDCS) with an intensity of 2 mA (HD-tDCS 2 mA); (2) 20-min of HD-tDCS with an intensity of 1.5 mA (HD-tDCS 1.5 mA); and (3) 20-min of sham HD-tDCS (HD-tDCS sham). The stimulation was administered noninvasively using an M x N 9-channel high definition transcranial electrical current stimulator from Soterix Medical (New York, NY). The anodal stimulation targeted the right Brodmann area 4 (primary motor cortex) based on HD-Targets brain modelling software (Soterix Medical, New York, NY). Tests: The non-dominant left arm was tested. The subjects performed a sequential point-to-point movement task on the graphics tablet. Initially, the participants were required to perform 3 sequences without errors to familiarize themselves with the setup, the task and the sequence. Then, they performed the pre-test which consisted of two blocks of 6 sequences, i.e. 12 sequences, with a 30 s break between blocks. Two min after starting the appropriate stimulation, they performed 2 blocks of 6 sequences (identical to the pre-test). After finishing the tDCS stimulation, the participants performed a post-test, which was also identical to the pre-test. The participants returned after 24 hours to perform a retention test, which was equivalent to the pre- and post-tests. Two outcome measures were used: movement time (s) and the reaction time (s) of the reaching movements.

Official Title
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The Effect of Transcranial Direct Current Stimulation Intensity on Motor Performance in Healthy Adults

Conditions
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Healthy

Intervention / Treatment
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* Device: HD-tDCS 2 mA
* Device: HD-tDCS 1.5 mA
* Device: HD-tDCS sham


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: aged between 20 and 35 right-hand dominant healthy according to self report Exclusion Criteria: taking psychiatric medications a history of drug abuse or dependence psychiatric or neurological disorder a history of seizures metal implants in their head musculoskeletal deficits interfering with task performance (proper reaching performance in sitting)

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: randomized controlled trial (RCT)
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HD-tDCS 2 mA<br>Single session of 20-min HD-tDCS to the right primary motor cortex with an intensity of 2 mA. The session lasted approximately one hour. The participants returned after 24 hours to perform a retention test. | Device: HD-tDCS 2 mA<br>* anodal high definition transcranial direct current stimulation of the right primary motor cortex with an intensity of 2 mA<br>|
| Experimental: HD-tDCS 1.5 mA<br>Single session of 20-min HD-tDCS to the right primary motor cortex with an intensity of 1.5 mA. The session lasted approximately one hour. The participants returned after 24 hours to perform a retention test. | Device: HD-tDCS 1.5 mA<br>* anodal high definition transcranial direct current stimulation of the right primary motor cortex with an intensity of 1.5 mA<br>|
| Sham Comparator: Control<br>Single session of 20-min of sham HD-tDCS. The session lasted approximately one hour. The participants returned after 24 hours to perform a retention test. | Device: HD-tDCS sham<br>* sham stimulation of the right primary motor cortex<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in movement time (s) from baseline to intervention | Time from movement onset (first time the tangential velocity was greater than 5% of the peak tangential velocity) until the end of the movement (the last time the tangential velocity was greater than 5% of the peak tangential velocity). Improved motor performance was indicated by a shorter movement time. | Baseline (immediately before stimulation), two minutes after starting the stimulation | 
| Change in movement time (s) from baseline to posttest | Time from movement onset (first time the tangential velocity was greater than 5% of the peak tangential velocity) until the end of the movement (the last time the tangential velocity was greater than 5% of the peak tangential velocity). Improved motor performance was indicated by a shorter movement time. | Baseline (immediately before stimulation), immediately post stimulation | 
| Change in movement time (s) from baseline to retention test | Time from movement onset (first time the tangential velocity was greater than 5% of the peak tangential velocity) until the end of the movement (the last time the tangential velocity was greater than 5% of the peak tangential velocity). Improved motor performance was indicated by a shorter movement time. | Baseline (immediately before stimulation), 24 hours following the stimulation | 
| Change in movement time (s) from intervention to posttest | Time from movement onset (first time the tangential velocity was greater than 5% of the peak tangential velocity) until the end of the movement (the last time the tangential velocity was greater than 5% of the peak tangential velocity). Improved motor performance was indicated by a shorter movement time. | Two minutes after starting the stimulation, immediately post stimulation | 
| Change in movement time (s) from intervention to retention test | Time from movement onset (first time the tangential velocity was greater than 5% of the peak tangential velocity) until the end of the movement (the last time the tangential velocity was greater than 5% of the peak tangential velocity). Improved motor performance was indicated by a shorter movement time. | Two minutes after starting the stimulation, 24 hours following the stimulation | 
| Change in movement time (s) from posttest to retention test | Time from movement onset (first time the tangential velocity was greater than 5% of the peak tangential velocity) until the end of the movement (the last time the tangential velocity was greater than 5% of the peak tangential velocity). Improved motor performance was indicated by a shorter movement time. | immediately post stimulation, 24 hours following the stimulation | 
| Change in reaction time (s) from baseline to intervention | Time between when the target appeared in green (changed color from white to green), and movement onset. Improved motor performance was indicated by a shorter reaction time. | Baseline (immediately before stimulation), two minutes after starting the stimulation | 
| Change in reaction time (s) from baseline to posttest | Time between when the target appeared in green (changed color from white to green), and movement onset. Improved motor performance was indicated by a shorter reaction time. | Baseline (immediately before stimulation), immediately post stimulation | 
| Change in reaction time (s) from baseline to retention test | Time between when the target appeared in green (changed color from white to green), and movement onset. Improved motor performance was indicated by a shorter reaction time. | Baseline (immediately before stimulation), 24 hours following the stimulation | 
| Change in reaction time (s) from intervention to posttest | Time between when the target appeared in green (changed color from white to green), and movement onset. Improved motor performance was indicated by a shorter reaction time. | Two minutes after starting the stimulation, immediately post stimulation | 
| Change in reaction time (s) from intervention to retention test | Time between when the target appeared in green (changed color from white to green), and movement onset. Improved motor performance was indicated by a shorter reaction time. | Two minutes after starting the stimulation, 24 hours following the stimulation | 
| Change in reaction time (s) from posttest to retention test | Time between when the target appeared in green (changed color from white to green), and movement onset. Improved motor performance was indicated by a shorter reaction time. | immediately post stimulation, 24 hours following the stimulation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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transcranial direct current stimulation, motor performance