What Researchers Did
Researchers followed up with military personnel who had taken part in two earlier US trials of hyperbaric oxygen (HBO₂) for ongoing symptoms after concussion, using a survey to check how they were doing months later.
What They Found
This was an observational follow-up survey of former HBO₂ trial participants, and only 40 of 132 eligible people (30%) completed it, about 39 months after their original trial. At follow-up, participants across both studies still reported symptoms of post-concussive syndrome, PTSD, anxiety, and reduced quality of life. In the DARPA/VCU study group, total post-concussive symptom scores worsened in the 1.5 ATA HBO₂ group (average change +7.4 points) while they improved in the sham group (-8.0 points) and the 2.0 ATA HBO₂ group (-3.3 points), though individual changes ranged widely from -23 to +28 points. In the HOPPS study group, scores worsened in all three groups: local care (+10.5), sham (+7.9), and 1.5 ATA HBO₂ (+1.0). The researchers state that symptoms did not appear to improve over time based on their descriptive analysis.
Canadian Relevance
No direct Canadian connection identified.
Study Limitations
Only 30% of the original 132 participants completed the follow-up survey, and the authors state that this low participation rate and potential response bias limited their ability to perform statistical testing or draw conclusions from the results.