Hyperbaric Oxygen Treatment Improves Cerebral Blood Flow in a Small Clinical Trial
In the study noted here, researchers provide evidence for a few months of hyperbaric oxygen treatment to increase blood flow to the brain, perhaps in large part by spurring greater growth of small blood vessels in brain tissue. In older patients this produced improvements in measures of cognitive function. There is a good deal of evidence in the literature to suggests that changes in blood flow to the brain cause altered cognitive function. Consider that exercise improves memory function, for example, both immediately following exercise, and then over the long term. Further, it is the case that capillary networks decline in density throughout the body with age, and this is thought to contribute to degenerative aging by lowering the flow of blood to energy-hungry tissues such as the brain and muscles.
Besides common pathological declines such as in Alzheimer's disease and mild cognitive impairments, normal cognitive aging is part of the normal aging process. Processing speed, conceptual reasoning, memory, and problem-solving activities are the main domains which decline gradually over time. Cerebrovascular dysfunction is an additional distinctive feature of aging that includes endothelial-dependent vasodilatation and regional decreases in cerebral blood flow (CBF). Although not associated with a specific pathology, reduced regional CBF is associated with impaired cognitive functions.
Hyperbaric oxygen therapy (HBOT) utilizes 100% oxygen in an environmental pressure higher than one absolute atmospheres (ATA) to enhance the amount of oxygen dissolved in body's tissues. Repeated intermittent hyperoxic exposures has been shown to induce physiological effects which normally occur during hypoxia in a hyperoxic environment, including stem cells proliferation and generation of new blood vessels (angiogenesis). Angiogenesis is induced mainly in brain regions signaling ischemia or metabolic dysfunction. In turn, neovascularization can enhance cerebral blood flow and consequently improve the metabolic activity.
A randomized controlled clinical trial randomized 63 healthy adults (older than 64) either to HBOT or control arms for three months. Primary endpoint included the general cognitive function measured post intervention/control. Cerebral blood flow (CBF) was evaluated by perfusion magnetic resonance imaging. There was a significant group-by-time interaction in global cognitive function post-HBOT compared to control. The most striking improvements were in attention and information processing speed. Analysis showed significant cerebral blood flow increases in the HBOT group compared to the control group.