Traumatic Brain Injury & Post-Concussion Syndrome

After a mild traumatic brain injury (concussion), a minority of patients develop persistent post-concussion syndrome — headache, slowed thinking, memory and attention problems and mood changes that can last for years. HBOT in this chronic phase is one of the most contested questions in hyperbaric medicine, and the trials point in different directions.

In favour: a randomised crossover trial in 56 adults 1–5 years after mild TBI (40 sessions of 60 minutes, 100% oxygen at 1.5 ATA) reported significant improvements in cognitive function and quality of life after HBOT but not during a no-treatment control period, with SPECT showing increased brain activity (Boussi-Gross 2013); and a sham-controlled, double-blind trial in 25 children aged 8–15 with persistent post-concussion syndrome (60 sessions of 60 minutes at 1.5 ATA, against a sham at near-surface pressure) reported improvements in cognitive and behavioural function, symptoms and quality of life, with MRI microstructural changes, although recruitment stopped before the planned sample size was reached (Hadanny 2022).

Against: a randomised, double-blind, sham-controlled trial in 60 active-duty marines with post-concussion symptoms persisting 3–36 months (40 sessions of 60 minutes) found no immediate benefit of oxygen exposures equivalent to 1.5 or 2.0 ATA over a sham gas mixture equivalent to breathing surface air, and concluded that the results do not support HBOT for cognitive, balance or fine-motor deficits (Walker 2014).

Interpretation hinges on the control arms. One review argues that pressurised-air controls (21% oxygen above 1.0 ATA, typically 1.2–1.3 ATA) are themselves therapeutically active, so trials using them are better read as dose comparisons, and grades the evidence as B-level (Figueroa & Wright 2016); a critical appraisal counters that no mechanism has been shown for such low-pressure exposures and that an apparent effect in both arms more likely reflects a participation effect (Bennett 2018).

Both positive trials come from a single Israeli research group (Assaf Harofeh, now Shamir Medical Center), and several authors of the 2022 trial declare commercial competing interests. The protocols studied — not a clinical recommendation — comprised 40–60 daily sessions of 60 minutes, 100% oxygen at 1.5 ATA, five days a week. HBOT for TBI and post-concussion syndrome remains investigational and is not FDA-approved.