New evidence explores HBOT as an adjunct to post-stroke rehabilitation

Stroke can have lasting consequences that extend well beyond the initial event.  For many survivors, the challenges continue long after hospital discharge, affecting memory, attention, concentration, movement, independence and overall quality of life.

A major area of ongoing research is how to support the brain's recovery following stroke.

A systematic review and meta-analysis published in Frontiers in Neurology on 13 October 2026 has added to this discussion, examining whether hyperbaric oxygen therapy (HBOT), when used alongside conventional treatment can improve cognitive function, neurological outcomes and everyday functioning in people experiencing post-stroke cognitive impairment.

What did the research investigate?

The research team, led by Hu and colleagues, analysed 35 randomised controlled trials involving 3,036 participants with post-stroke cognitive impairment.

The researchers compared conventional treatment with conventional treatment supplemented by HBOT.  Depending on the individual study, conventional care including medication, physiotherapy, cognitive training and other interventions.

The review evaluated several established clinical measures:

• Montreal Cognitive Assessment (MoCA):  Assesses cognitive abilities including memory, attention, language and executive functioning.

• Mini-Mental State Examination (MMSE):  Evaluates general cognitive function.

• National Institutes of Health Stroke Scale (NIHSS):  Measures the severity of neurological impairement.

• Modified Barthel Index (MBI) and Barthel Index (BI):  Assess independence in everyday activities such as dressing, bathing, and mobility.

Rather than examining a single trial, the researchers combined results from multiple studies to estimate the overall effect of adding HBOT to conventional care.

What did the 2026 meta-analysis find?

The results showed statistically significant improvements across all five outcome measures in the groups receiving adjunctive HBOT.

Cognitive function improved.  The primary outcome was the Montreal Cognitive Assessment (MoCA).  Participants receiving HBOT alongside conventional treatment had scores that were, on average, 2.90 points higher than those receiving conventional treatment alone.

The researchers also found an average improvement of 2.68 points on the MMSE.

These findings show a benefit for cognitive performance following stroke.  Depending on the individual, this is relevant to difficulties with attention, memory, processing information and executive function.

Neurological impairment showed improvement.  The researchers also examined the NIHSS, a clinical scale used to assess neurological deficits.

The pooled analysis found an average reduction of 2.61 points in the HBOT groups compared with controls.  Lower NIHSS scores indicate less severe neurological impairment.

Improvement in everyday independence.  Recovery is not measured by cognitive testing alone.   The ability to perform everyday tasks and regain independence is equally important to many stroke survivors.

The analysis found improvements in both measures of daily functioning.  Modified Barthel Index increased by an average of 6.64 points.  Barthel Index increased by an average of 8.77 points.

These findings show HBOT has a role alongside rehabilitation aimed at improving functional independence.

Why might oxygen matter in neurological recovery?

The brain has a high metabolic demand and relies on a continuous supply of oxygen to support cellular energy production.  Following an ischaemic strike, a reduction or interruption in blood flow deprives affected tissue of oxygen and nutrients.  The resulting injury can initiate a complex cascade involving inflammation, oxidative stress, mitochondrial dysfunction, and damage to neural cells.

Recovery is influenced by many factors, including the extent and location of the original injury, the restoration of blood flow, the brain's capacity for adaptation and the rehabilitation provided.

HBOT involves breathing oxygen at a pressure greater than normal atmospheric pressure.  This increases the amount of oxygen dissolved directly into the blood plasma, in addition to the oxygen carried by haemoglobin.

The increased oxygen partial pressure creates a stronger driving force for oxygen diffusion from the blood into surrounding tissues.  This is particularly relevant to understanding the physiological rationale for HBOT, although the effect in any individual brain region depends on factors including blood flow, tissue condition and the treatment protocol.

Researchers are investigating several potential mechanisms through which HBOT might influence neurological recovery:

Oxygen availability and cellular metabolism

Increased oxygen availability supports aerobic energy production in viable tissue.  Neurons require substantial energy to maintain electrical signalling, cellular repair and normal function.

Inflammatory signalling and oxidative stress

HBOT can influence cellular signalling pathways associated with inflammation and oxidative stress.  These effects are complex and depend on the oxygen dose, pressure, treatment frequency and the condition of the tissue.

Mitochondrial function

Mitochondria are responsible for much of the cell's energy production.  HBOT has been found to influence mitochondrial function and cellular resilience in injured neurological tissue.

Neuroplasticity and vascular adaptation

Neuroplasticity refers to the brain's ability to reorganise connections and function.  Research is showing positive results associated with neural repair and vascular adaptation.

What about treatment pressure and frequency?

The trials in the review used different HBOT protocols.  Reported pressures ranged from 1.8 ATA to 2.2 ATA (atmospheres absolute), with many studies using 2.0 ATA.  Treatment durations and number of sessions also varied.

The researchers did not identify statistically significant differences in cognitive outcomes according to treatment pressure or the number of sessions in their meta-regression analyses.

At Hyperbaric Health NZ, we believe that understanding the limitations and taking an individualised approach are essential when discussing hyperbaric oxygen therapy and neurological health.

- Samantha Winters