Two 20-seat hyperbaric chambers at the Sagol Center were used in the study (Credit: Sagol Center for Hyperbaric Medicine and Research, Israel)

Two 20-seat hyperbaric chambers at the Sagol Center were used in the study (Credit: Sagol Center for Hyperbaric Medicine and Research, Israel)

Hyperbaric oxygen therapy (HBO) is a recognized treatment for deep-sea divers experiencing decompression sickness (The Bends); for carbon monoxide poisoning; and for some soft-tissue wounds. The technique involves breathing oxygen via a mask in a pressurised single- or multi-person hyperbaric chamber. In the UK today, many MS national therapy centres have hyperbaric chambers because of the anecdotal evidence that HBO can help the symptoms of MS. These centres often welcome patients with other diseases too, and many people with ME have taken up this opportunity to try HBO at very reasonable cost.

But does HBO really help reduce the symptoms of ME/CFS? In 2006, Action for ME’s Interaction magazine published an overview of members’ experiences of various ‘oxygen therapies’, including HBO. Some found HBO helpful for alleviating certain symptoms, such as brain fog or concentration, but others reported no lasting improvement. As regards scientific research, there have been only two smallish experimental studies on ME/CFS patients; one reported unspectacular, mostly non-significant results when HBO was given daily for one week (Van hoof 2003), while the other (an uncontrolled trial) reported that HBO given daily for three weeks decreased symptom severity and increased quality of life (Akarsu 2013) . So, there is as yet no convincing evidence (anecdotal or experimental) that HBO can benefit most people with ME/CFS.

The results of a new scientific report from Israel come as quite a surprise, therefore. They present evidence that HBO can have a dramatic benefit in fibromyalgia – a condition which also affects many ME/CFS patients, given that the two illnesses share many symptoms and overlap diagnostically. The researchers at the Sagol Center for Hyperbaric Medicine and Research at the Assaf Harofeh Medical Center were studying people with post-traumatic brain injury when they decided to explore the use of HBO in fibromyalgia patients, whose principal complaint is chronic widespread pain. In their study, 48 female fibromyalgia patients, who had been ill for 6.5 years on average, received HBO; half of the group had a “control’ period of no treatment followed later by HBO, while the other half were given HBO immediately at the start of the trial. In total, each woman had 40 sessions of HBO over 8 weeks (90 minutes per session at 100% oxygen at 2 atmospheres).

Overall, HBO led to significant reduction in the number of fibromyalgia ‘tender points’, and in the tenderness of these points. There were also improvements in physical functioning and quality of life. But the most intriguing finding came from SPECT imaging of the brain, which indicated that HBO ‘rectified’ the functioning of certain brain areas believed to be abnormal in fibromyalgia. Activity in the posterior brain region (which is responsible for pain processing, and may be hyperactive in fibromyalgia) was reduced by HBO. By contrast, activity in the frontal areas of the brain (which are responsible for inhibiting pain and may be hypo-active in fibromyalgia) was increased by HBO. Also, there was intriguing evidence that the ‘normalisation’ of brain activity in these areas coincided with improvements in symptoms.

Quite why HBO should ‘rectify’ abnormal brain activity in pain-related areas is unclear, but the authors speculate that raising oxygen concentrations to very high levels may alter brain metabolism and improve the functioning of the glial cells which support and protect central and peripheral nerve cells. It may be that, as lead author Dr Shai Efrati says, “brain repair, including even neuronal regeneration, is possible even for chronic, long-lasting pain syndromes”. It would be fascinating indeed to see these results reproduced and confirmed by others.

Of course, not everyone finds the idea or experience of HBO pleasant. In this study, for example, 7 patients refused to enter the hyperbaric chamber and had to be excluded from the investigation, and a further 4 patients decided to drop out during treatment due to dizziness, claustrophobia and inability to adjust to the hyperbaric conditions. Again, though HBO is usually well-tolerated by patients, the MS Society warns on its website that mild visual side-effects sometimes occur and, on very rare occasions, people have also experienced severe adverse affects such as pressure injury to the ear, collapsed lungs and seizures. So, it is wise for patients to err on the safe side, and speak to their GPs before undergoing a course of HBO.

Sources
Hyperbaric oxygen therapy can diminish fibromyalgia syndrome – prospective clinical trial. Efrati S, et al. PLoS One, 2015 May 26; 10(5): e0127012. Read more (full text).
Press release: Hyperbaric hope for fibromyalgia sufferers. Rice University, Houston, Texas. June 2015. Read more.

Picture credit
Two 20-seat hyperbaric chambers at the Sagol Center were used in the study (Credit: Sagol Center for Hyperbaric Medicine and Research, Israel)