Optimizing Current and Electrode Montage for Transcranial Direct Current Stimulation in Stroke Patients

Study Overview
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Brief Summary
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The purpose of this study is to determine the optimal transcranial direct current stimulation (tDCS) amplitude and electrode montage that is both safe and efficacious

Detailed Description
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Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that can modulate cortical excitability of targeted brain regions. Various studies have investigated tDCS use in stroke patients with motor impairments (cumulatively about 200 cases). Although these studies are mostly proof of concept with small sample size, they do suggest that tDCS may improve motor function. However these two questions have not been addressed systematically: What is the optimal current for stroke patients? What is the optimal tDCS electrode montage for stimulation? This proposal lays the scientific foundation for systematic application of tDCS in stroke recovery research by progressively increasing tDCS currents and montages that are both safe and efficacious in population with stroke.

Official Title
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Optimizing Current and Electrode Montage for Transcranial Direct Current Stimulation in Stroke Patients

Conditions
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Stroke

Intervention / Treatment
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* Device: transcranial direct current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18-80 years old with a first-ever ischemic stroke that occurred at least 6 months ago; Finished rehabilitation therapy(including inpatient or outpatient Physical Therapy (PT) / Occupational Therapy (OT) / Speech Therapy (SP)) at least one month ago; Unilateral limb weakness with Fugl Meyer-Upper Extremity Scale score less than 56 (out of 66); Motor Evoked Potentials (MEP) is inducible on abductor pollicis brevis (APB) muscle on the affected side by TMS. Exclusion Criteria: Primary intracerebral hematoma, or subarachnoid hemorrhage, Bihemispheric ischemic strokes; History of prior stroke or old infarct demonstrated on the CT or MRI or documented in medical records; Other concomitant neurological disorders affecting upper extremity motor function; Documented history of dementia before or after stroke; Documented history of uncontrolled depression or psychiatric disorder either before or after stroke which could affect their ability to participate in the experiment; Uncontrolled hypertension despite treatment, specifically Systolic blood pressure (SBP)/ Diastolic Blood Pressure (DBP) >= 180/100 mmHg at baseline; Presence of any MRI/tDCS/TMS risk factors: a) an electrically, magnetically or mechanically activated metal or nonmetal implant including cardiac pacemaker, intracerebral vascular clips or any other electrically sensitive support system; b) non-fixed metal in any part of the body, including a previous metallic injury to eye; c) pregnancy, since the effect of tDCS on the fetus is unknown; d) history of seizure disorder or post-stroke seizure; e) preexisting scalp lesion, bone defect or hemicraniectomy.

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Determine the Optimal tDCS current<br>We will invesitigate the optimal curent in range of 1 mA to 4 mA. We hypothesize that 4 mA is tolerable, safe and can induce the highest level of cortical excitability in the lesional motor cortex. | Device: transcranial direct current stimulation<br>* brain stimulation using progressively increasing amounts of direct currents and in a variety of electrode montages<br>* Other names: tdcs;|
| Experimental: Determine the optimal tDCS electrode montage<br>We hypothesize that the bi-hemispheric stimulation with anodal stimulation on the lesional hemisphere and simultaneous cathodal stimulation on the non-lesional hemisphere induces more cortical excitability in the lesional hemisphere than either anodal stimulation on the affected hemisphere or cathodal stimulation on non-lesional hemisphere alone. | Device: transcranial direct current stimulation<br>* brain stimulation using progressively increasing amounts of direct currents and in a variety of electrode montages<br>* Other names: tdcs;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Major Response | Major response is any of the following: Second degree scalp burn at the site of electrode pad; or Seizure; or New lesion(s) on Diffusion Weighted Imaging (DWI) sequence of MRI scan and the lesion(s) not explained by any other cause(s) or decreased Apparent Diffusion Coefficient (ADC) under the electrode stimulating motor cortex area; Discontinuation of subject from the study due to any of above. In a 3+3 design, 3 subjects are recruited for a given tDCS dose level. The trial is stopped if ≥2 of 3 subjects at a given tDCS dose level show major response. If only 1 of 3 subjects shows major response, 3 more subjects are recruited at a given tDCS dose level and a major response in any of them will stop the trial. Otherwise, same procedure is followed for the next tDCS dose level. Maximum tolerable dose will be the tDCS dose at the level before stopping of the trial. | Immediately after intervention on the day of tDCS application | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Transcranial Direct Current Stimulation, tDCS