Following multiple randomized and randomized controlled studies, the review found HBOT at 1.5 ATA oxygen to provide improvements in symptoms and cognition for patients with mild traumatic brain injury. These improvements — ranging from solely symptomatic to both cognitive and symptomatic — are significant enough to satisfy recommendations set in place for HBOT treatments by the Center for Evidence-Based Medicine and American Society of Plastic Surgeons. The systematic review concludes that HBOT meets the highest level of scientific evidence and merits a Grade A Practice Recommendation, that HBOT should be delivered to patients with persistent postconcussion syndrome unless a “clear and compelling rationale for an alternative approach is present.”