Individualizing tDCS Dose

Study Overview
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Brief Summary
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Transcranial direct current stimulation (tDCS) is a noninvasive method of modulating brain activity and has therapeutic potential in many neurological and psychiatric conditions. However, unlike every current FDA-approved form of brain stimulation, there is no method of individualizing stimulation dose. In this study, a method of individualizing tDCS dose on behavioral outcomes and whether this could help to improve the consistency and magnitude of the stimulation effects will be tested.

Official Title
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Testing the Effects of Individualized and 4mA tDCS

Conditions
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tDCS, Motor Function

Intervention / Treatment
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* Device: Sham transcranial direct current stimulation
* Device: Individualized transcranial direct current stimulation
* Device: 2mA transcranial direct current stimulation
* Device: 4mA transcranial direct current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy volunteers or chronic stroke participants (at least 6 months prior to the study) No history of epilepsy No metal in the body No contraindications for TMS or MRI scanning Right handed Ability to find motor hotspot and acquire motor evoked potentials Exclusion Criteria: Metal in the body History of epilepsy or claustrophobia Alcohol or substance abuse or dependence Current treatment for any psychiatric conditions (pharmacological or otherwise) Pregnant or actively breastfeeding

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Sham stimulation<br> | Device: Sham transcranial direct current stimulation<br>* Participants will receive 30 seconds of ramp up and down stimulation at the start and end of the 20 minute stimulation period.<br>|
| Experimental: Individualized stimulation<br> | Device: Individualized transcranial direct current stimulation<br>* Participants will receive 20 minutes of transcranial direct current stimulation (tDCS) at the individualized dose (maximum of 4mA).<br>|
| Experimental: 2mA stimulation<br> | Device: 2mA transcranial direct current stimulation<br>* Participants will receive 20 minutes of transcranial direct current stimulation (tDCS) at a 2mA dose.<br>|
| Experimental: 4mA stimulation<br> | Device: 4mA transcranial direct current stimulation<br>* Participants will receive 20 minutes of transcranial direct current stimulation (tDCS) at a 4mA dose.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Motor Evoked Potential Variance | MEP variance is measured by single pulses of transcranial magnetic stimulation and contralateral hand electrodes. | Baseline and post-stimulation (20 minutes apart) | 
| Difference in Motor Evoked Potential Amplitudes from 4mA and 2mA Stimulation | MEP amplitude is measured by single pulses of transcranial magnetic stimulation and contralateral hand electrodes. | Baseline and post-stimulation (20 minutes apart) |