- Hyperbaric oxygen therapy (HBOT) improved cognitive function in patients treated for sudden hearing loss and chronic wounds, according to a new Polish study.
- Researchers tested 53 patients before and after HBOT using standardized cognitive assessments.
- Both patient groups showed cognitive decline at baseline compared to healthy norms.
- After HBOT, significant improvements appeared in memory, attention, and processing speed for most patients.
- Older age and greater baseline cognitive impairment predicted smaller improvements after treatment.
A study published in Scientific Reports in January 2026 found that hyperbaric oxygen therapy improved cognitive function in patients receiving treatment for idiopathic sudden hearing loss and chronic hard-to-heal wounds.
Researchers at Nicolaus Copernicus University in Poland evaluated 53 patients aged 26 to 83. The cohort included 23 women and 30 men. Twenty-three patients received HBOT for idiopathic sudden sensorineural hearing loss. The remaining 30 patients received HBOT for chronic wounds that had resisted standard treatment.
The research team, led by Monika Betyna-Białek, Kinga Grobelska, and Alina Borkowska, assessed cognitive function before and after HBOT using five standardized neuropsychological tests: the Mini Mental State Examination (MMSE), Verbal Fluency Test, Trail Making Test, Rey Auditory Verbal Learning Test (RAVLT), and Color Word Interference Stroop test. These assessments measure memory, attention, processing speed, verbal ability, and executive function.
Baseline Findings
Both patient groups showed cognitive decline at baseline. Patients with chronic wounds performed worse on most cognitive tests compared to patients with hearing loss before treatment began.
This finding aligns with existing research on the cognitive effects of chronic illness. A 2020 study in Current Neurology and Neuroscience Reports found that diabetes is associated with memory impairment, and many patients with chronic wounds have underlying metabolic conditions.
Results After Treatment
After completing HBOT, both groups showed significant improvement in most cognitive parameters.
Patients with hearing loss improved on verbal fluency, memory recall, attention, and processing speed. Patients with chronic wounds showed similar gains.
(Ed. note: The convergence of results across two different patient populations strengthens the case that HBOT itself drives cognitive improvement, rather than disease-specific factors.)
The researchers found no significant difference between the two groups on seven verbal test parameters after treatment. This suggests HBOT may have a normalizing effect on verbal cognitive function regardless of the underlying condition being treated.
Some test parameters did not change significantly. In the hearing loss group, first-trial learning and word recall after distraction on the RAVLT showed no significant improvement, nor did phonological verbal fluency. In the chronic wound group, word recall after distraction also remained unchanged.
Age and Baseline Function Matter
Before HBOT, older age correlated with worse cognitive performance in both groups. This relationship persisted after treatment for chronic wound patients on the Trail Making Test, which measures processing speed and mental flexibility.
The hearing loss group showed no significant age-related correlations after treatment. The researchers suggest this may indicate HBOT partially compensates for age-related cognitive decline in some patient populations.
Patients with worse baseline MMSE scores showed less improvement overall. The MMSE is a screening tool for general cognitive impairment. Lower scores indicate more severe decline.
How HBOT May Affect the Brain
The study authors cite several potential mechanisms for HBOT’s cognitive effects. Hyperbaric oxygen therapy delivers 100% oxygen at increased atmospheric pressure, which raises oxygen levels in blood and tissues.
According to a 2021 review in Biomolecules, HBOT may improve brain metabolism, promote synaptic plasticity, stimulate neurogenesis, and reduce inflammation. These effects could explain improvements in memory and attention.
A 2022 systematic review in Neuropsychological Review by Marcinkowska and colleagues examined HBOT’s impact on cognitive function across multiple studies. The authors found evidence supporting cognitive benefits in various neurological conditions, though they noted the need for more randomized controlled trials.
Research on HBOT for post-stroke patients has shown similar results. A 2020 study in Restorative Neurology and Neuroscience found that HBOT improved neurocognitive function in stroke patients, with benefits appearing even years after the initial stroke.
Study Limitations
The study did not include a control group receiving sham treatment, which limits the ability to rule out placebo effects. The sample size of 53 patients is relatively small. The researchers used non-parametric statistical tests appropriate for the sample size.
The manuscript published in Scientific Reports is an early access version. The authors note it will undergo further editing before final publication.
Clinical Implications
The findings add to growing evidence that HBOT may benefit cognitive function beyond its primary therapeutic applications. Patients receiving HBOT for conditions like chronic wounds or sudden hearing loss may experience secondary cognitive improvements.
Clinicians treating older patients or those with baseline cognitive impairment should be aware that these patients may see smaller cognitive gains from HBOT. However, the treatment still produced measurable improvements in most cognitive domains across both patient groups.
The study was conducted at a Polish university hospital. The researchers reported no competing interests.
References
- Betyna-Białek M, Grobelska K, Borkowska A. The impact of hyperbaric therapy on cognitive functions in patients treated for idiopathic sudden hearing loss or hard-to-heal chronic wounds. Sci Rep. 2026. https://www.nature.com/srep
- Gotfried I, Schottlender N, Ashery U. Hyperbaric oxygen treatment-from mechanisms to cognitive improvement. Biomolecules. 2021;11(10):1520. https://doi.org/10.3390/biom11101520
- Marcinkowska AB, Mankowska ND, Kot J, Winklewski PJ. Impact of hyperbaric oxygen therapy on cognitive functions: a systematic review. Neuropsychol Rev. 2022;32(1):99-126. https://doi.org/10.1007/s11065-021-09500-9
- Hadanny A, et al. Hyperbaric oxygen therapy improves neurocognitive functions of post-stroke patients – a retrospective analysis. Restor Neurol Neurosci. 2020;38(1):93-107. https://doi.org/10.3233/RNN-190959
- Arvanitakis Z, Tatavarthy M, Bennett DA. The relation of diabetes to memory function. Curr Neurol Neurosci Rep. 2020;20(12):64. https://doi.org/10.1007/s11910-020-01085-9
