The most common traumatic brain injury (TBI)-associated problems are cognitive deficits and neuropsychiatric problems, such as sleep disturbance and PTSD. This study evaluates a novel neuromodulation intervention, light emitting diodes (LED), for treatment of patients with TBI. LED is a noninvasive, non-thermal, painless treatment, which does not involve any needles or any form of surgery. LED treatment improves cellular activity of the brain tissue that has been damaged by TBI. Half of the study participants will receive active LED treatment, and a control group will receive sham LED. This study takes place in Boston, Massachusetts: at the VA Boston Healthcare System.