This is a preliminary, prospective interventional study to investigate the feasibility of using transcutaneous alternating current stimulation (TACS) after a traumatic brain injury (TBI) to improve cognitive function and decision-making.

All participants engaged in the study will participate once weekly for six weeks at Hennepin Healthcare Systems, Inc. (HHS). Each participant will be randomized into the block design of sham or tACS during the first three appointments or the last three appointments. While participating, both the tACS will be applied in accordance with the manufacturer's suggested use. Participants will complete computer-based tasks, while taking part in either the sham or tACS stimulation. The study is investigating the use of neuromodulation after Traumatic Brain Injury (TBI) for improved cognitive function.

Inclusion Criteria:

• Adults 18 years and older
• Diagnosis of a mild to moderate TBI (GCS > 8 on admission)
• Able to perform a computerized assessment
• Willing to attend all scheduled appointments
• Able to undergo the informed consent process

Healthy participants:

• Adults 18 years and older
• Able to perform a computerized assessment
• Willing to attend all scheduled appointments
• Able to undergo the informed consent process

Exclusion Criteria:

• Open wound on scalp
• Severe TBI diagnosis or GCS of less than 8 on admission
• Non-English speaking
• Incarcerated
• Implanted defibrillator or pacemaker
• Visual impairment that hinders ability to complete computerized assessments

Healthy subject exclusion criteria:

• Less than 18 years of age
• Open wound on scalp
• TBI diagnosis
• Non-English speaking
• Incarcerated
• Implanted defibrillator or pacemaker
• Visual impairment that hinders ability to complete computerized assessments

Participants are blinded to stimulation versus no stimulation.