Clearing the Air: CFI White Paper and Media Release on Hyperbaric Oxygen Treatment for Autism
June 08, 2010
Hyperbaric Oxygen Treatment for Autism - Clearing the Air
CFI White Paper:
Autism Spectrum Disorders (ASD) are a form of developmental disability in children that, to date, are not very well understood. They are characterized by difficulties in sociality and communication as well as a restriction of interests, which may also be accompanied by stereotypical and repetitive behaviours. Recently there has been an increased use of hyperbaric oxygen therapy (HBOT) for the treatment of ASD, with some studies suggestive that it may have beneficial effects based on a number of behavioural parameters (1,2).
These earlier experiments may have been overly optimistic. It has been theorized that HBOT is useful in the treatment of autism by increasing the intake of oxygen which would reduce inflammation and increase oxygen concentration in the brain. However, at this time it is not generally agreed that inflammation or lack of oxygen is a cause of, or even associated with autism. It is also a costly treatment garnering from $100-200 a session with a minimum recommendation of 40 sessions. These treatments are currently not covered by health care providers and must be borne by parents or primary caregivers.
A hyperbaric chamber is a pressurized chamber with an enriched oxygen atmosphere. It has been found to be useful when treating the "bends" which can result when a diver surfaces too quickly causing gas bubbles to form in the bloodstream and may also be useful in the treatment of wounds. There are two types of pressurized chambers: “hard” in which the oxygen content is 100% and “soft” where the oxygen content is elevated to various levels below 100% (3). Normal atmospheric oxygen content is 21%.
Due to the lack of medical evidence for the cause of ASD, let alone the treatment of the symptoms, a number of "alternative" treatments are in use by parents who are desperate to help their children. These include: acupuncture, holistic approach to neurodevelopment and learning efficiency (HANDLE), homeopathy, music therapy, service dogs, neurofeedback and swimming therapy (3). HBOT has been studied in rat models where it was found to help reduce brain damage in neonates that had previously been exposed to low levels of oxygen (4) and also in a reduction in damage to the blood brain barrier after blood flow was restricted (5). However, until recently there have been few studies on what, if any, effects HBOT has in the treatment of ASD.
Prior to 2009 no clinical trials had been conducted and studies suffered from small sample size, lack of proper controls and a lack of statistical significance between treatment groups (1,6). The efficacy of HBOT was largely confined to speculative statements such as: “It is conceivable that the cerebral hypoperfusion (decreased blood flow) found in autistic children may be triggered by neuroinflammation and therefore may be reversible with anti-inflammatory modalities" (6), and "It is speculated that treatment with hyperbaric oxygen may also help reduce oxidative stress in autistic children" (6). However, in 2009 (2) and 2010 (7) two new double blind (where neither the subjects nor experimenters know which is the treatment group) placebo-controlled studies with conflicting conclusions have been published and bear further examination.
A 2009 study by Rossignol et al. (2) found support for the use of HBOT. However, while the experimental design and execution were rigorous for a randomized, double-blind trial, the study suffers from a major statistical flaw which brings its conclusions into question. In this paper there was a treatment group that received HBOT and another group that did not, and both the subjects and experimenters were blind to what treatment groups were assigned to. The researchers measured a baseline level of ASD based on three indices [one of which has been discredited (7)] and then measured the degree of improvement within the two groups. There were no comparisons between the placebo and treatment groups, which is essential to determine if there was any benefit for treatment with HBOT As a result, no firm conclusions about the usefulness of HBOT in the treatment of ASD can be made based on the results of this study.
The 2010 study by Granpeesheh et al. (7) is highly critical of the 2009 study by Rossignol et al. (2), and rightly so given the creative statistical analysis employed by Rossignol et al. 2009. One of the major problems with Rossignol et al. 2009 is that the number of times you make comparisons between the treatment (HBOT) and placebo group, the more likely you are to claim you have a significant result when you shouldn't have. In other words the Rossignol paper has a high probability of accepting a false result. In the Granpeesheh et al. 2010 study the responses based on a number of behavioral measures demonstrated that the placebo group actually did better than the treatment (HBOT) group . To their credit Granpeesheh et al. 2010 also did a more rigorous analysis over time and found no difference between the two groups, a procedure and analysis that Rossignol et al. 2009 ignored and as such weakened their study. Granpeesheh et al. 2010 also found that in weekly behavioral measures both the placebo and treatment groups improved with time, and that there was no difference between the two. In summary Granpeesheh et al. 2010 conclude: "This study found HBOT to have no significant beneficial effect on ASD symptoms. The experimental design of the current study is of a higher rigor than those employed in previous studies which have suggested that HBOT is effective" (7).
In conclusion, while the causes, treatment and cure of ASD are unknown at this time, it is critical to have scientific, clinical, properly administered double blind trials to assess new or alternative therapies. It is becoming apparent that there may be a strong genetic component to ASD, and the majority of the recent research papers have focused on this (8). However, at the present time the scientific evidence suggests that there are no significant benefits to ASD children who are treated with HBOT. We must use the tools of analysis that science gives us to determine how best to help those children who suffer from ASD. Finally, at this time it is disingenuous to promote the use of HBOT to parents who are seeking to help their children and will do so at any cost. It is difficult for parents or primary caregivers not to seek out whatever treatment they believe would help their children, regardless of cost, but unfortunately their money appears to be ill spent, and it is better to use current established therapies such as applied behavior analysis (ABA) for ASD.
(1) Rossignol, D.A., Rossignol, L.W., James, S.J., Melnyk, S. and Mumper, E. 2007. The effects of hyperbaric oxygen therapy on oxidative stress, inflammation, and symptoms in children with autism: an open-label pilot study. BMC Pediatrics 7 :36.
(2) Rossignol, D.A. Rossignol, L.W. Smith, S., Schneider, C., Logerquist, S., Usman, A., Neubrander, J., Madren, E.M., Hintz, G., Grushkin, B. and Mumper, E.A. 2009. Hyperbaric treatment for children with autism: a multicenter, randomized, double-blind, controlled trial. BMC Pediatrics 9 :21.
(3) http://www.autismcanada.org/hyperbaric.htm
(4) Calvert, J.W., Yin, W., Patel, M., Badr, A., Mychaskiw, G., Parent, A.D., Zhang, J.H. 2002. Hyperbaric oxygenation prevented brain injury induced by hypoxia–ischemia in a neonatal rat model. Brain Research 151 :1-6.
(5) Veltkamp, R., Siebing, D.A. Sun, L., Heiland, S., Bieber, K., Marti, H.H., Nagel, S., Schwab, S. and Schwaninger,M. 2005. Hyperbaric Oxygen Reduces Blood-Brain Barrier Damage and Edema After Transient Focal Cerebral Ischemia. Stroke 36 :1679-1683
(6) Rossignol, D.A. and Rossignol, L.W. 2006. Hyperbaric oxygen therapy may improve symptoms in autistic children. Medical Hypotheses 67 :216-228.
(7) Granpeesheh, D., Tarbox, J., Dixon, D.R., Wilke, A.E., Allen M.S., Bradstreet J.J. Randomized trial of hyperbaric oxygen therapy for children with autism. 2010. Research in Autism Spectrum Disorders 4 :268–275.
(8) Matson, J.L. and Smith, K.R.M. 2009. Trends and topics in autism spectrum disorders research. Research in Autism Spectrum Disorders 3 :252-257.