 This study aims to evaluate the efficacy of 4 weeks of daily light exposure in reducing Post-Traumatic Brain Injury TBI Fatigue immediately post-treatment and at a one-month follow up. The investigators hypothesize that individuals receiving 4 weeks of bright white light treatment will report significant reductions in fatigue compared to individuals receiving dim red light treatment for the same duration of time, and that these treatment effects will be maintained one month after treatment completion. 