HBOT for Persistent Symptoms After Brain Injury: What Does the 2025 Research Tell Us?
For people who continue to experience symptoms months or even years after a brain injury, recovery can sometimes feel like it has stalled.
Headaches, dizziness, fatigue, poor sleep, difficulty concentrating, memory problems, anxiety, tinnitus, and other neurological or emotional symptoms can persist long after the original injury.
The 2025 study
The study, led by Lindell K. Weaver and colleagues, was a double blind, randomised, sham-controlled clinical trial.
The researchers recruited adults who had experienced a brain injury at least 6 months, and up to 10 years, previously. The injuries included traumatic brain injury (TBI), carbon monoxide poisoning and hypoxic brain injury. People post-stroke were specifically excluded from this study.
Participants needed to have at least three persistent symptoms associated with their brain injury. These included symptoms such as:
Headaches
Dizziness or balance problems
Fatigue and sleep difficulties
Problems with memory or problem-solving
Anxiety or depression
Post-traumatic stress symptoms
Irritability
Tinnitus
Importantly, these weren't people recovering from a recent injury. They were people living with persistent symptoms long after their original brain injury.
40 sessions of HBOT
The participants were randomly assigned to receive either 40 HBOT sessions or 40 sham chamber sessions. The HBOT group treatment dose consisted of 1.5 ata, 100% oxygen for 60 mins per session. The sham group received room air, 1.1 ata for 60 mins per session.
The sessions were delivered over approximately 12 weeks.
The primary outcome was measured using the Neurobehavioural Symptom Inventory (NSI), a questionnaire designed to assess the severity of symptoms commonly experienced after brain injury.
There was then longer-term follow-up, including the opportunity for participants to receive another 40 HBOT sessions.
What did they find?
This is where the study becomes particularly interesting.
After 40 sessions, the HBOT group demonstrated a significantly greater reduction in overall neurobehavioural symptoms than the sham group.
The average improvements in NSI score was:
10.6 points in the HBOT group vs 3.6 points in the sham group.
The HBOT group also demonstrated improvements across all three NSI domains: cognitive, affective and somatic symptoms.
Specific improvements were also seen in areas including olfaction, anxiety, sleep difficulties and vestibular complaints.
What about longer treatment?
One of the most interesting aspects of this study was its longer-term design.
Three months after the initial 40-session series, participants were offered another 40 sessions of HBOT.
Among the original HBOT group, the researchers observed additional improvements in NSI scores following the second series, with outcomes assessed at 12 months.
The authors therefore concluded that 80 HBOT sessions may be superior to 40 sessions for long-term brain injury outcomes.
Why might HBOT help?
Brain injury is complex.
The original injury may occur at one point in time, but changes involving blood flow, oxygen availability, inflammation, cellular metabolism and tissue function can persist.
HBOT increases the amount of oxygen available to tissues by combining increased pressure with increased oxygen. This creates a substantially greater oxygen gradient and can increase oxygen delivery beyond what can be achieved by breathing oxygen at normal atmospheric pressure.
The theory behind HBOT for persistent brain injury is therefore not simply 'more oxygen is better', rather, the interest lies in how pressure and increased levels of oxygen influence the biological environment in which injured or dysfunctional tissue is trying to recover.
Research into HBOT and brain injury has investigated potential effects involving tissue oxygenation, vascular function, inflammation, cellular metabolism and neuroplasticity.
Why this study matters
This 2025 study is valuable because it used a randomised, double-blind, sham-controlled design and followed participants over a longer period.
It also looked at people with persistent symptoms occurring months to years after their brain injury, rather than focussing only on the acute phase of injury.
Perhaps one of the most interesting messages from this research is that the brain may retain capacity for improvement long after the initial injury. Recovery isn't confined to the days or weeks immediately following an injury. Creating the right physiological environment to support the body's ongoing repair and adaptation processes allows an injury cycle to transform into a healing cycle. The conversation around HBOT and brain injury is moving beyond anecdotal reports and into increasingly rigorous clinical research.
The science is evolving, as is the mountain of anecdotal evidence. This is why we keep learning.
- Samantha Winters
