The primary aim of this study is to assess the magnitude of transcranial direct current stimulation (tDCS) -induced cognitive and functional change in patients with mild traumatic brain injury. This study will also attempt to identify biomarkers associated with treatment response. Last, acceptability and tolerability of procedures will be assessed. To accomplish these aims, a randomized, double-blind, sham-controlled, parallel groups, pilot study will be conducted in which participants are assigned to 24 sessions of tDCS or sham stimulation offered concurrent with working memory training. Neural efficiency will be measured with electroencephalogram (EEG) pre and post-intervention.

Transcranial direct current stimulation (tDCS) is a safe, non-invasive neuromodulation technique that shows promise as an intervention technique. The primary aim of this study is to assess the magnitude of tDCS-induced cognitive and functional change in patients with mild traumatic brain injury (TBI). In this double-blind, sham-controlled, pilot study, 24 veterans with mild TBI will be randomized to tDCS or sham conditions. Stimulation will be administered with a StarStim neurostimulator at 2 milliamps (mA) for 20 minutes. The anodal electrode will be placed over the left dorsal lateral prefrontal cortex. Twenty-four sessions of stimulation will be administered concurrent with 20 minutes of working memory training. Participants will continue with an additional 40 minutes of working memory training post-stimulation. Participant experience with neuromodulation will be assessed with a self-report questionnaire that lists common reactions to tDCS. Participant perception of the value of neuromodulation procedures will be assessed at weeks 4 and 8. A second aim is to identify biomarkers of treatment response. Resting state electroencephalogram (EEG) will be collected at three time points: prior to the first tDCS training session, immediately after the first training session, and post-intervention. This study will provide preliminary evidence of the efficacy of providing tDCS as an intervention to enhance cognitive and functional outcomes for individuals with mild traumatic brain injury. Furthermore, the results of this study will also increase the understanding of the mechanisms by which tDCS enhances cognitive performance. This knowledge has the potential to provide insight into the underlying therapeutic process as well as to guide development of the next generation of interventions. In addition, acceptability of the intervention will be monitored to identify potential barriers to administering tDCS in clinical practice.

Inclusion Criteria:

• Veterans enrolled at the Minneapolis Veterans Affairs (VA) Health Care System
• Age of 18 and 65
• Sustained a mild traumatic brain injury more than 1 year ago.

Exclusion Criteria:

• Presence of a psychotic disorder
• Severely depressed
• Clinically unstable due to a hospitalization or medication change in the previous 4 weeks
• Mild substance use disorder in the last month
• Moderate to Severe substance use disorder in the last six months
• Behavioral problems that prevent participation in a group intervention
• Premorbid intellectual ability (IQ) below 70
• Unable to provide informed consent
• Have a guardian of person
• Have another existing neurological condition that impacts cognitive functioning
• Not fluent enough in English to understand testing procedures
• Have a medical condition that is incompatible with transcranial direct current stimulation.