Inclusion Criteria: Participants are to be between the ages of 18-75, have previously served in the US armed services, and have had a traumatic brain injury that has led to 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: Exclusion criteria include a history of a psychological or neurological disorder, including, dementia of any type, epilepsy or other seizure disorders, severe traumatic brain injury, 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. Additionally, exclusion criteria include inability to give informed consent; cranial implants or skull defects that affect tDCS administration; and use of medications that interact with or potentially interact with tDCS effects, including, anti-convulsants, amphetamines, L-dopa, carbamazepine, sulpiride, pergolide, lorazepam, rivastigmine, dextromethorphan, D-cycloserine, flunarizine, ropinirole, or citalopram.