Using Transcranial Direct Current Stimulation (tDCS) to Improve Post-Stroke Aphasia

Can Enhancing Left Lateralization Using Transcranial Direct Current Stimulation Improve Recovery From Post-Stroke Aphasia?

This study tests whether weak electrical stimulation of the brain is effective in improving language or reading difficulties occurring after a brain injury or stroke.

This study tests whether aphasia or alexia, language and reading disorders occurring after traumatic brain injury or stroke, can be improved using transcranial direct current stimulation (tDCS). tDCS is a non-invasive technique that applies a small amount of direct electrical current to the brain in order to temporarily alter brain processing. Adults with aphasia/alexia resulting from stroke or traumatic brain injury will undergo baseline behavioral testing of various language and cognitive functions. Subjects who are willing to undergo MRI evaluation will also be scanned. They will then receive five days of either real or sham tDCS with standardized speech-language therapy, under a double-blind randomized placebo-controlled design. Behavioral assessments, and MRIs for those participating in the MRI portion of the study, will be performed again at multiple time points after completing tDCS to assess for changes in these measures.

Inclusion Criteria:

• Age 18 or older
• Aphasia due to left hemisphere stroke diagnosed by a physician or speech-language pathologist

Exclusion Criteria:

• Skull defect at or near the site of tDCS delivery
• History of a significant stroke or traumatic brain injury other than the event that caused the aphasia
• History of other brain conditions that could impact interpretation of results (such as multiple sclerosis, brain tumor, encephalitis, premorbid dementia)
• Presence of implanted electrical or metallic devices in the head or body (except titanium; e.g. cochlear implants, implanted shunts with metal parts, deep brain stimulators, pacemakers, defibrillators)
• Presence of ferrous metal in the head (e.g. shrapnel)
• History of psychiatric disease requiring hospitalization, electroconvulsive therapy, or ongoing medication use (other than common selective serotonin reuptake inhibitor antidepressants)
• Pregnancy
• Severe comprehension deficits

Additional Exclusion Criteria for the optional MRI portion of the study:

• Presence of metal in the body (except titanium)
• Claustrophobia