February 22, 2013

Stroke Recovery Years Later

Many brain cells that have been damaged by stroke are not dead. Hyperbaric treatment helps them regenerate even years later.

An Israeli study shows that high-pressure oxygen treatments can help stroke victims recover lost abilities months or even years after their strokes. In the study, patients showed significant improvement up to three years post-stroke.

Every patient who received the treatment showed progress in both neurological function and quality of life.

These cells are still capable of regeneration, but that requires much more energy than they have been getting. The extra oxygen from the hyperbaric treatments provides that energy and makes regeneration possible.

Blood can carry up to ten times more oxygen throughout the body if the oxygen is administered at higher-than-normal air pressure. Such pressurized oxygen deliveries are called hyperbaric oxygen treatments (HBOT) and have been used to help scuba divers recover from the the rapid depressurization problems known as "the bends."

According to the researchers, after a stroke there are many brain cells that have been damaged, but are not dead. Even though they have survived, the stroke-damaged brain cells are stunned, unable to the fire the electrical signals that they should be sending. These cells are still capable of regeneration, but that requires much more energy than they have been getting. The extra oxygen from the hyperbaric treatments provides the energy that makes regeneration possible.

The 59 patients in the study showed differing degrees of recovery. Some regained lost language ability and were able to walk, climb stairs, bathe and dress on their own, after needing help to perform all these activities previously. Others made more modest gains, but all did make gains.

The researchers sought stroke patients whose condition was no longer improving. Half were given 40 HBOT treatments over two months, 90 minutes a treatment, five times a week. For each session, patients were placed in a sealed chamber where they inhaled 100% oxygen at two atmospheres pressure. The other half were left untreated for two months and then received two months of oxygen treatments as per the other group.

Because patients can tell when they're breathing air under increased pressure, it was not possible to run a typical blinded controlled study. And because higher pressure will cause additional oxygen to dissolve in the blood even when breathing normal air, the only way for the researchers to run such a control would have been to place these patients in a chamber with lower than normal oxygen content, which was deemed unethical.

Instead, what the researchers used as a control was a comparison of the improvement in the control group from two months of oxygen treatments to two months of no treatment at all.

Both brain scans and the patients' own assessments showed significant improvement after receiving the oxygen treatments and no improvement during the two untreated months. The researchers think oxygen therapy may also be able to help people with other neurological conditions, such as Alzheimer's disease. They are also currently studying its effects on traumatic brain injury.

The study was published in PLoS ONE and is freely available.

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