Transcranial Direct Current Stimulation to Enhance Training Effectiveness in Chronic Post-Stroke Aphasia

Prior treatment

• epilepsy with seizures during the last 12 months prior to study start and/or intake of sedating antiepileptic drugs (barbiturates and benzodiazepines),
• changes in centrally active drugs within 2 weeks prior to study inclusion.

Other illness

• contraindications for tDCS (e.g., cardiac pacemaker, history of seizures, implanted metal inside the head);
• more than one clinically apparent stroke with aphasic symptoms;
• other severe neurological diseases (e.g., brain tumor, and subdural hematoma);
• history of severe alcohol or drug abuse;
• current psychosis or other relevant psychiatric condition;

Other

• current severe depression;
• very severe apraxia of speech, as revealed by Hierarchical Word Lists;
• severe non-verbal cognitive deficits, as indicated by the Corsi Block-Tapping Task;
• severe uncontrolled medical problems;
• severely impaired vision or hearing that prevents patients from engaging in intensive SLT;

• left-hemisphere cortical or subcortical stroke with first-ever aphasic symptoms
• at least 6 months post-onset of stroke;
• aphasia, as determined by the Aachen Aphasia Test (AAT);
• 13 moderate-to-severe word finding difficulties (maximum of 75% correct items on a computerized naming task at baseline);
• at least 1 correct reaction on the first part of the AAT subscale Token Test (ensuring basic comprehension skills);
• at least 1 point on the communicative task of the AAT subscale Spontaneous Speech (ensuring basic communication abilities);
• German as first language;
• intact left-hemisphere "hand knob" without right prefrontal lesions for placement of tDCS electrodes, as confirmed by magnetic resonance imaging or computer tomography scans.