Treating Civilian Traumatic Brain Injury With High Definition Transcranial Direct Current Stimulation (ciTBI-HDtDCS)

Inclusion Criteria: Participants are to be between the ages of 18-85, are non-military personnel and not veterans, and have had a traumatic brain injury (more than a year ago prior to study participation) that has led to a complaint of word finding difficulty since the brain injury, confirmed to represent a verbal retrieval deficit based on neuropsychological testing criteria. Traumatic brain injury must be in the mild to moderate range based on evaluation, including the Ohio State TBI Identification Method (administered by our research group). You must be fluent in speaking and reading English. Exclusion Criteria: * an implanted/electronic device, such as a pacemaker, metallic cranial or intracranial implant (e.g., ventriculoperitoneal shunt), or a neurostimulator (e.g., vagus nerve stimulator, spinal stimulator, deep brain stimulator, etc.). * skull defects * a history of a psychological or neurological disorder, including, dementia of any type, epilepsy or other seizure disorders, post-traumatic stress disorder, brain tumor, present drug abuse, stroke, blood vessel abnormalities in the brain, Parkinson's disease, Huntington's disease, or multiple sclerosis. * inability to give informed consent * currently pregnant * not a native English speaker