American Academy of Cerebral Palsy and Developmental Medicine
United Cerebral Palsy Research and Educational Foundation
United Cerebral Palsy Associations
Status Report on Unsubstantiated Interventions
"Present Status of Hyperbaric Oxygen Therapy for the Treatment of Cerebral Palsy"

Forward Cerebral palsy and other neurodevelopmental disorders are characterized by the presence of functional impairments and disabilities that can interfere with activities of daily living. Conventional therapies and interventions often do improve functional status but may not provide the degree of functional improvement and independence that persons with a disability or their parents or caregivers desire. As a result, a number of unsubstantiated approaches to improve to improve function have been proposed in the past and new but unsubstantiated approaches are regularly being offered. Some are based upon new applications of methods used for other purposes; others are a founded on ideas and practices that are at variance with currently accepted concepts of human biology and clinical care. There is often an initial burst of enthusiasm about results by those participating in unconventional interventions; however, the enthusiasm generally disappears as the results are found to be less than expected, only transitory, or not beneficial enough to justify the additional investment in time or funds.

Unsubstantiated interventions are rarely supported by research studies that meet accepted standards. The reports are often anecdotal; that is, the observation of participants about their own or someone else's experience. On occasion, a report of an organized series of experience is available ( a "case series"). However, none of these reports provides the type of evidence required to make an accurate judgement about the intervention's safety, its adequacy or its relative benefit. Also, there is generally no organized body of reliable evidence to demonstrate when thee intervention fails to work. Failure is rarely reported in anecdotal reports of unsubstantiated treatments. Asa important as anecdotal reports can be to draw attention to an unsubstantiated intervention, only carefully designed clinical trails can provide the evidence necessary to properly assess its role and the appropriateness of its incorporation a part of "mainstream" treatment.

Unsubstantiated approaches that propose to diminish disability and improve function, but which have not been evaluated in carefully designed clinical trials are regularly being offered to the public. In order to be of assistance, we offer these comments on hyperbaric oxygenation in the treatment of cerebral palsy so that the public can come to decisions based on what is known and not known at this time.

HYPERBARIC OXYGEN FOR CEREBRAL PALSY: A STATUS REPORT
Hyperbaria is the term used to describe a procedure in which a person is placed in an enclosed chamber in which the atmospheric pressure of air is gradually increased, maintained, then gradually decreased. It is used for the treatment of decompression illness ("the bends"), a condition brought on by too rapid decompression when coming to the surface rapidly after a deep dive or when people working under increased atmospheric pressure return to normal atmospheric pressure too rapidly (e.g. escaping from undersea vessels; building tunnels under rivers).


Hyperbaric oxygenation is the term used to describe a procedure in which an increased amount of oxygen is added to the air breathed under hyperbaric conditions, sometimes 100% oxygen. Under increased pressure, oxygen is made more available to red blood cells (the usual transporters of oxygen in the blood); in addition, oxygen is also dissolved in the fluid (plasma) of the blood. Thus, additional oxygen becomes available to the body's tissues as the oxygen-enriched blood circulates.

Hyperbaric oxygenation is medically accepted for use in a number of conditions including the treatment of carbon monoxide poisoning, gangrene, skin ulceration and sometimes to support the growth of skin grafts used in the treatment of burns. It is not a harmless procedure in that too much oxygen can be very harmful to tissues and can cause important blood vessels in the brain and heart to constrict; also oxygen under pressure may cause a pneumothorax (collapsed lung). The delivery of hyperbaric oxygen must be done by experts under very carefully controlled conditions.

During the past few years, a few clinicians have explored the use of hyperbaric oxygenation in a variety of conditions such as stroke, head injury, spinal cord injury, and multiple sclerosis. At this time, the published scientific literature does not support the use of this technique in any of these conditions. A major problem has been the lack of well designed clinical trails utilizing a scientifically acceptable protocol to evaluate the usefulness of the procedure for the conditions. Reports of success are anecdotal and are very difficult to evaluate for reliability or validity. On the other hand, neither has it been demonstrated that the procedure fails to work.

Thus, there is no acceptable evidence available at this time to support either conclusion: it works; it doesn't work. This is also true at this time in regard to the use of hyperbaric oxygenation in the treatment of developmental brain damage such as cerebral palsy or in the treatment of the impairments (e.g. spasticity) or disabilities (e.g. decreased mobility) associated with it. There is no scientifically acceptable evidence available at this time that demonstrates its clinical usefulness; neither is there any scientifically acceptable evidence available at this time demonstrating its lack of usefulness. Individual stories ("anecdotes") tell very little; they are interesting, provocative, but not scientifically informative.

Comment: There is no biological basis for assuming that increased oxygen availability will have any effect on established lesions due to a developmental brain disorder in the brain of a person with disabilities.

However, it is believed by some of the proponents of hyperbaric oxygenation that there are areas adjacent to the brain lesion which they consider to be non-functional but alive; they also believe these areas can be made functional by hyperbaric oxygenation and this will result in improved performance. It is also believed by some proponents that unaffected or undamaged areas of the brain will be stimulated by increased oxygen availability and will take over the function of damaged areas of the brain. These are hypotheses that need to be tested. As of now, they are based on conjecture and on inferences drawn from poorly designed or unrelated studies.

The clinical usefulness of hyperbaric oxygen therapy in the treatment of the disabilities associated with cerebral palsy is presently based only on individual anecdotes. Its usefulness has not been put to the test using research methods essential for its evaluation. A few clinical case series have been reported; a few pilot studies utilizing organized protocols of evaluation are said to have been done, but the methodologies and their results have not been published in the published in the peer reviewed scientific literature.

Although not yet demonstrated, it is conceivable that hyperbaric oxygenation may be of help to selected persons with certain kinds of disabilities. If it is helpful, it is not known whether beneficial effects are short-lived or permanent. It is also conceivable that any positive results at best are marginal and/or temporary. Finally, it is equally conceivable that hyperbaric oxygenation has no beneficial effects.

We urge clinicians who support the use of hyperbaric oxygenation in the treatment of disabilities associated with cerebral palsy to develop and launch well designed clinical trails to evaluate its usefulness and to publish their results so the medical community can review them and the public can be informed. The initiative for these studies is theirs; the responsibility is theirs to demonstrate that they believe is true.

For the time being, we urge persons interested in the use of hyperbaric oxygenation in cerebral palsy to be cautious about the interpretation of anecdotes about its usefulness and we encourage families to seek advice from a number of professionals and families who have had their children participate. Also, we urge families t make certain that the physicians providing the therapy are expert in BOTH hyperbaric medicine and in developmental brain injury.

United Cerebral Palsy Research and Education Foundation, October 1999