Impact of Transcranial Direct Current Stimulation of the Motor Cortex on Language Functions in Residual Aphasia

Study Overview
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Brief Summary
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The present study assesses whether language functions in patients with residual post-stroke aphasia can be improved by transcranial direct current stimulation administered to the primary motor cortex in the language dominant (left) hemisphere.

Detailed Description
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Patients will participate in two tDCS sessions (atDCS; sham) in a cross-over within subjects design. tDCS or placebo will be administered during simulatneous fMRI to assess neural signatures of the stimulation. Order of stimulation will be counterbalanced between subjects

Official Title
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Impact of Transcranial Direct Current Stimulation of the Motor Cortex on Language Functions in Residual Aphasia

Conditions
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Residual Aphasia

Intervention / Treatment
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* Device: atDCS
* Device: sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: right handedness German native speaker cerebrovascular stroke in left hemisphere (>6 months) mild aphasia (according to Aachen Aphasia Test Battery Classification, Huber et al., 1983) residual anomia in naming test (>75 correct responses) Exclusion Criteria: other current or previous neurological or psychiatric diseases alcohol or drug abuse MRI contraindication (e.g. magnetic metal, pacemaker, claustrophobia)

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: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: anodal tDCS<br>atDCS will be administered for 20 minutes with 1 milliampere (1 mA) to the left primary hand motor cortex | Device: atDCS<br>* atDCS will be delivered with a constant current of 1 mA during simultaneous resting-state (RS) and task-related (picture naming) functional magnetic resonance imaging (fMRI). The current will be turned on prior to the RS-fMRI scan and continues for 20 minutes.<br>Device: sham tDCS<br>* During sham the current will be increeased and decreased in a ramp-like fashion (10 sec)<br>|
| Sham Comparator: sham tDCS<br>sham tDCS will be administered to the left primary hand motor cortex | Device: atDCS<br>* atDCS will be delivered with a constant current of 1 mA during simultaneous resting-state (RS) and task-related (picture naming) functional magnetic resonance imaging (fMRI). The current will be turned on prior to the RS-fMRI scan and continues for 20 minutes.<br>Device: sham tDCS<br>* During sham the current will be increeased and decreased in a ramp-like fashion (10 sec)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Response latency during picture naming task (max. 80) | Subjects are assessed in a cross-over design. The primary outcome measure will be assessed twice in each subject, either during placebo (sham) stimulation or active (anodal) stimulation with transcranial direct current stimulation. Order of stimulation will be counterbalanced across the group. | Change in response latency between assessment 1 (week 1) and assessment 2 (week 2), assessments 1 and 2 are seperated by one week | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in neural activity measured by functional magnetic resonance imaging |  | Change in fMRI activity between Assessment 1 (week 1) and Assessment 2 (week 2), assessments 1 and 2 are seperated by one week |