HYPERBARIC OXYGEN THERAPY
(Cerebral Palsy)

Page 9 of 10

Hyperbaric oxygenation requires the use of greater than normal atmospheric pressure to deliver a high dosage of oxygen. This form of therapy, which corrects lack of oxygen not just in the blood but in the tissues, is developing rapidly around the World. To understand why more oxygen may help some people with cerebral palsy it is necessary to explain the background to the condition. There are some obvious questions to be answered:

When does the damage occur?

Ultrasonic scanning of the brain has shown that the events which cause the development of cerebral palsy almost certainly occur at the time of birth, (1) although it may be many months before spasticity develops. The areas affected are in the middle of the hemispheres of the brain and one side or both sides may involved. These critical areas, called the internal capsules, are where the fibers from the controlling nerve cells in the gray matter of the cortex of the brain pass down on their way to the spinal cord. In the spinal cord they interconnect with the nerve cells whose fibers finally activate the muscles of the legs and arms. Although anatomists have called these areas the internal "capsules," they are not encapsulated at all; the boundaries are formed by other zones of the brain.

Unfortunately, the internal capsules have a poor blood supply, which is shown by the frequent occurrence of damage to these areas shown by Magnetic Resonance Imaging (MRI) in younger patients with multiple sclerosis and in strokes in the elderly. When an event causes lack of oxygen the blood vessels leak, the tissues become swollen and there may even be leakage of blood. The increased water content, termed oedema, interferes with the transport of oxygen. These changes apply to any tissue, but a sufficient quantity of oxygen is vital both to the function and, in people, development of the brain.

When the controlling nerve cells in the brain are disconnected from the spinal cord, the signals to the arms and legs cannot pass and the ability to move is lost. Eventually, because the nerve cells in the spinal cord are separated from the control of the brain, they send an excess of signals to the muscles, causing the uncontrolled contractions known as spasticity. The areas carrying the controlling nerve fibers to the legs are the closest to the ventricles of the brain where the blood supply is poorest (3) so the legs are the most commonly affected. The condition is called diplegia, to indicate that the problem is in the brain to distinguish it from paraplegia where the problem is in the spinal cord.

Can spasticity delayed?

This is a crucial question that is, at present, not adequately explained. People who develop spasticity often appear to develop normally for several months and then lose function gradually. Because in many people there is voluntary movement for a time after birth the connections must be intact. Why then are they lost allowing spasticity to develop? The answer almost certainly is due to the failure of the coverings of the nerve fibers, known as myelin sheaths, to develop and the evidence has come from MRI. Myelin sheaths envelop the nerve fibers like a Swiss roll in order to increase the speed with which impulses can be transmitted. Myelination normally begins about a month before birth and progresses to completion by the age of two. If there is tissue swelling in the mid-brain the delicate cells that form myelin die and the nerve fibers are left exposed and slowly deteriorate with the development of spasticity.

What may be possible?

Loss of function in the brain can be either due to tissue swelling, which is reversible, or tissue destruction, which is not. The recoverable areas can now be identified by a technique called SPECT imaging. The initials stand for Single Photon Emission Computed Tomography. It can demonstrate blood flow which is linked to metabolism of the brain which is, of course, directly related to oxygen availability. By giving oxygen at the high dosages possible under Hyperbaric conditions areas which are not "dead but sleeping" can be identified. This phenomenon has been discussed for many years in stroke patients and authorities have even stated that the critical parameter is not blood flow it is oxygen delivery. (4) Under normal circumstances blood flow and oxygen delivery are inextricably coupled, but the use of Hyperbaric conditions can change this situation. Tissue oedema and swelling may persist in for example, joints, for many years and SPECT imaging has now revealed that this is true in the brain. Suggesting that more oxygen that is additional oxygen supplied under hyperbaric conditions may be of value generates further questions:

What does Hyperbaric mean?

It means a pressure greater than normal sea-level atmospheric pressure. Atmospheric pressure at sea level varies with the weather and on a high-pressure day more oxygen is available to the body. Aches and pains may be worse on a low-pressure day because of the reduction of oxygen pressure. A Hyperbaric chamber allows much more oxygen to be dissolved in the blood. An indication of the power of this technique is that at twice atmospheric pressure breathing pure oxygen that the work of the heart is reduced by 20% (5) So much can be dissolved in the plasma that life is possible for a short time without blood’ The research behind the development of Hyperbaric oxygen therapy has been done by doctors involved in aviation, space exploration and diving. The information is not yet taught in our Medical Schools despite thousands of published articles.

How can cerebral palsy people be helped?

Clearly the appropriate time to use of oxygen is at the start of a disease process, not after a delay of months or years. Nevertheless, a course of oxygen therapy sessions at increased pressure has been shown to resolve tissue swelling after the lapse of years. It works by constricting blood vessels and interrupting the vicious cycle where oxygen lack leads to tissue swelling, which then leads to further oxygen deficiency.

Although formal studies have yet to be undertaken in people with cerebral palsy there is every reason to believe that exactly the same effect that is seen in stroke patients can occur. Also in people the brain is still developing and therefore the prospects for improvement are very much greater. Recovery of brain damage in people as a result of cardiac surgery has been documented using X-ray scanning. 

Will oxygen therapy cure cerebral palsy? 

Hyperbaric oxygen therapy is not a miracle cure for people with cerebral palsy; it is simply a way of ensuring the most complete recovery possible. It should be used with exercise programs, because lack of use in muscles and joint leads to changes that can only be reversed by exercise.

A great deal of the medical research in the UK is funded by the drug industry and the costs involved are enormous. As the use of oxygen cannot be patented, there is no way that the cost of trials can be recouped and no finance is available for the promotion of the therapy. Because of the great advances made in the use of drugs a climate has been created in which doctors are conditioned to expect a drug-based solution to every disease. Oxygen has been available in Medicine for over a hundred years so it is difficult to accept that it is not being used properly, but over 500 chambers are now operating in the USA and Japan, 1500 in Russia and a similar number in China. As is so often the case much of the original research was undertaken and published in the UK. In many diseases the cost of investigations is often a great deal more than the cost of providing hyperbaric oxygen therapy. MRI and SPECT imaging may allow the benefit to be demonstrated, but they are not in any way therapeutic. There is no better assessor of a person suffering from cerebral palsy than a parent or care person involved in the day-to-day hands on care.

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