Effect of tDCS on Brain Organization and Motor Recovery

Study Overview
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Brief Summary
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Neurological deficits and motor disorders are extremely common after stroke. Physical therapies can improve the autonomy of these patients, but despite an intensive stationary neurorehabilitation, severe deficits often persist. Complementary therapies that could improve recovery would therefore be very welcome. Transcranial direct current stimulation (tDCS) induces, in a non-invasive way, a transient inhibitory or excitatory neuromodulation of certain cerebral regions. An increasing number of studies show that this modulation of brain activity can improve motor functions in patients with brain lesions and increase the effect of physical therapies. However, the optimum configuration of tDCS and the induced effects remain to be characterized and investigated. The investigators therefore propose to carry out a study including a pilot phase in order to determine the most efficient tDCS setup. The optimum setup of of the pilot phase will be compared to a placebo condition in a multicentric main study.

Official Title
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Effects of Transcranial Direct Current Stimulation (tDCS) on Brain Organization and Motor Recovery After Stroke

Conditions
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Stroke

Intervention / Treatment
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* Device: DC-stimulator (Neuroconn, Germany)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ischemic or hemorrhagic stroke ≤ 4 weeks after stroke onset Paresis of upper limb with Fugl-Meyer score between 15 and 55 at study entry Capable of participating during treatment sessions of 30-60 minutes Informed consent obtained Exclusion Criteria: Incapacity to understand study information or task instructions during trial. New additional stroke during rehabilitation Reduced vigilance or delirium Severe language deficits Preexisting affection of an upper limb Severe spasticity or dystonia Severe co-morbidities (e.g., traumatic, rheumatologic, neurodegenerative disease) Pregnancy Pacemaker Skull breach History of seizures or epilepsy Metallic object in the brain Other contraindication to non-invasive brain stimulation

Ages Eligible for Study
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Minimum Age: 18 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: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Anodal tDCS<br>The anode is placed over the primary motor cortex of the stroke affected hemisphere, the cathode over the contralesional supraorbital front of the patient. | Device: DC-stimulator (Neuroconn, Germany)<br>* A current of 2 mA will be applied for 20 minutes, 3 times per week during 2 weeks, except for the sham tDCS arm.<br>|
| Active Comparator: High definition (HD) anodal tDCS<br>A single HD anode is placed over the primary motor cortex of the stroke affected hemisphere, 4 HD cathodes are placed over the affected hemisphere around the anode. | Device: DC-stimulator (Neuroconn, Germany)<br>* A current of 2 mA will be applied for 20 minutes, 3 times per week during 2 weeks, except for the sham tDCS arm.<br>|
| Active Comparator: Bihemispheric tDCS<br>The anode is placed over the primary motor cortex of the stroke affected hemisphere, the cathode over the primary motor cortex of the contralesional hemisphere. | Device: DC-stimulator (Neuroconn, Germany)<br>* A current of 2 mA will be applied for 20 minutes, 3 times per week during 2 weeks, except for the sham tDCS arm.<br>|
| Sham Comparator: Sham tDCS<br>The electrodes are placed as in one of the active arms, but only a ramp up current is applied during 30 seconds and then switched off. This induces similar sensations for the patients, but no change in excitability. | Device: DC-stimulator (Neuroconn, Germany)<br>* A current of 2 mA will be applied for 20 minutes, 3 times per week during 2 weeks, except for the sham tDCS arm.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in upper extremity Fugl-Meyer score, after intervention | Scale range 0-66 points, higher values indicate better outcome. Assessed by qualified physical or occupational therapists | Difference between the week before the intervention and the week after intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in EEG functional connectivity, after intervention | EEG functional connectivity between ipsilesional motor cortex and the rest of the brain, as computed from high-density EEG recordings. Continuous measure. Higher values indicate better outcome. | Difference between the week before the intervention and the week after intervention | 
| Change in amplitude of motor evoked potentials, after intervention | Motor evoked potentials are obtained with single-pulse transcranial magnetic stimulation. Continuous measure expressed in microvolts, more microvolts indicate better outcome. | Difference between the week before the intervention and the week after intervention |