This Phase II, double-blind, sham-controlled trial evaluated hyperbaric oxygen therapy (HBO₂) in 71 U.S. military personnel with persistent symptoms following mild traumatic brain injury (mTBI). Participants received 40 sessions of either HBO₂ (1.5 ATA, >99% oxygen) or sham treatment (1.2 ATA, room air) over 12 weeks. At 13 weeks, the
