 A double blind randomized trial of light-emitting diode LED therapy for patients suffering from mild traumatic brain injury mTBI. Patients seen in the Sports Concussion Clinic with cognitive symptoms lasting for greater than 4 weeks will be randomized to either placebo therapy controls or treatment with LED therapy cases. Both cases and controls would complete post-concussion symptom scales Delis-Kaplan Executive Function System D-KEFS, and ImPACT studies on entry into the study and at weeks 3 and 6, or earlier if their symptoms resolve before the end of the 6 week period. 