Improvement of memory impairments in poststroke patients by hyperbaric oxygen therapy.

Objective: Several recent studies have shown that hyperbaric oxygen (HBO₂) therapy carry cognitive and motor therapeutic effects for patients with acquired brain injuries. The goal of this study was to address the specific effects of HBO₂ on memory impairments after stroke at late chronic stages.

Method: A retrospective analysis was conducted on data of 91 stroke patients 18 years or older (mean age ∼60 years) who had either ischemic or hemorrhagic stroke 3-180 months before HBO₂ therapy (M = 30-35 months). The HBO₂ protocol included 40 to 60 daily sessions, 5 days per week, 90 min each, 100% oxygen at 2ATA, and memory tests were administered before and after HBO₂ therapy using NeuroTrax's computerized testing battery. Assessments were based on verbal or nonverbal, immediate or delayed memory measures. The cognitive tests were compared with changes in the brain metabolic state measured by single-photon emission computed tomography.

Results: Results revealed statistically significant improvements (p < .0005, effect sizes medium to large) in all memory measures after HBO₂ treatments. The clinical improvements were well correlated with improvement in brain metabolism, mainly in temporal areas.

Conclusions: Although further research is needed, the results illustrate the potential of HBO₂ for improving memory impairments in poststroke patients, even years after the acute event.