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Treating Autism with Hyperbaric Oxygen Therapy

Rebecca Lee

October 5, 2009


What is hyperbaric oxygen therapy?


        In the last decade the use of hyperbaric oxygen therapy has become an increasingly popular alternative treatment for individuals with Autism. Hyperbaric oxygen therapy, HBOT, is a procedure in which a person breathes oxygen that is between 1.5 and 3.0 times normal atmospheric pressure while inside of a sealed chamber ( The body is able to absorb greater amounts of oxygen due to the fact that gases dissolve in liquids more readily with increased pressure, the phenomenon known as Henry’s Law of Physics ( Advertisements claim the pressure also allows the oxygenated blood to travel to parts of the body that are “difficult to reach” with greater ease. Hyperbaric therapy is a legitimate and effective treatment for burn victims and scuba divers suffering from “the bends.” However, because of the mixed results for Autism treatment, HBOT is ill-advised and not currently approved by the FDA or covered by insurance (

          Although testimonials of miraculous recoveries and improvement by leaps and bounds after a small number of treatments can easily be found on the web sites for clinics offering the treatment and companies trying to sell chambers for use at home, the fact remains that the procedure has flaws. HBOT sessions add up to a hefty bill very quickly, but seem reasonable compared to the prices of home units for approximately $15,000. Without coverage from insurance, a single session ranges from $100-150, with recommendations to return multiple times a week. The home chambers all over the web become appealing after a while with all of the promises made, but that does not guarantee the treatment will affect one child just like another. The vendors of hyperbaric chambers may be feeding off of the desperation of frustrated parents seeking a cure that has not been found for Autism with very high prices.


How does HBOT treat Autism?

        Autism Spectrum Disorders are developmental disabilities with varying degrees of impairment characterized by challenges in social, behavioral, and communication skills. The causes of ASDs are not completely understood but are currently believed to include both environmental and biological factors, including genetics Typical interventions include speech therapy and Applied Behavior Analysis for modifying existing behavior and teaching new skills. Parents of children with Autism are advised to be wary of alternative treatments and consult their child’s doctor before beginning an unconventional treatment such as HBOT.

Based on the somewhat controversial belief that ASDs are caused by oxygen deficiencies and inflammation in areas of the brain responsible for communication, advertisements for HBOT claim it is supposed to increase cerebral blood flow and excite inactive neurons ( Hyperbaric therapy is also said to reduce excess fluids and swelling in the brain which would benefit neurological functioning. HBOT forces the constriction of blood vessels and may have the ability to stimulate the temporal lobe, a major region of the brain affected by Autism. Improved activity in the temporal lobe in particular could help improve behavioral issues and reduce confusion.

Is it safe?

        Because HBOT is relatively new and inadequately studied for Autism at the present time, little is known about the costs or benefits for long-term health. Hyperbaric therapy is also new to children, who may react differently from adults. The studies conducted in the last four years have found that HBOT can trigger seizures and some patients experience claustrophobia while inside the sealed chamber ( Participants had to leave one study due to increased asthma symptoms and anxiety (Rossignol, 2009). More commonly, children receiving the procedure experience bruising of the eardrums and sinus pain. While none of the side effects discovered thus far have been terribly threatening, it is important to avoid treatments that have not been endorsed by the FDA because of possible adverse health effects. Recent evidence suggests the usefulness of HBOT and an approval by the FDA may soon follow, but it is currently considered risky to administer to your child.


What studies have been done?

          As of March 2009, only one randomized clinical trial has been conducted on HBOT for individuals with Autism. Dr. Rossignol is a leading authority on the procedure and has been involved in multiple uncontrolled studies as well as the only truly meaningful study, which may lead to the endorsement of the FDA in the near future. Dr. Daniel Rossignol works at the ICDRC in Florida in a facility claiming to integrate “traditional science and medicine with recently developed therapies” ( The website offers a clinic that will provide hope and answers for families affected by a developmental disorder, a very appealing message to families touched by Autism. Rossignol has two children of his own on the Spectrum, which would undeniably generate a tremendous motivation to find an effective and safe treatment.

        The first study conducted by Rossignol was based on the hypothesis that if oxygen can stimulate the areas of the brain that control sensory perception, social interaction, and impairments in communication, HBOT would reduce symptoms of Autism (Rossignol, 2006). The retrospective study of six individuals previously diagnosed with Autism treated each subject with 40 one hour sessions of HBOT at 1.3 ATA over a three month time span. The 2-7 year old subjects were allowed to continue all current therapies and to add new ones during the HBOT exposure. Parent rated pre-treatment and post-treatment evaluations were used to assess each subject using the ATEC, CARS, and SRS scales for symptoms such as verbal communication and sensory/cognitive awareness. The results showed a greater improvement in children under age 4 than older children, but the study had numerous flaws. First, there was no control group for adequate comparison with the treatment so the developmental changes, such as walking and talking, could have occurred naturally. Second, the study had a very small number of participants, which means the results are not easily generalized to other individuals on the Spectrum and the study had low external validity. Third, the assessment based on subjective observation by the parents is at risk for a belief bias in the effectiveness of the treatment when they desperately want to see improvement in their child. Finally, because the subjects were allowed to make other changes in their medication or behavioral intervention, it cannot be concluded that HBOT directly caused the results.

        The following year Rossignol and his colleagues completed another study, this time with more participants and two pressurized groups (Rossignol, 2007). The first group received 1.3 atm and the second group 1.5 atm.  Children with PDD and Asperger Syndrome were excluded from the study as well as children with a history of seizures. In order to truly determine the validity of HBOT, the 3-16 year old participants were not allowed to begin any new therapies or stop their current therapies. The treatment for administered 40 times per child for 45 minutes each session. The parents assessed the level of communication, interaction, social motivation, and social cognition of the subjects with the SRS, ATEC, and ABC-C scales. Following treatment, the children demonstrated decreased irritability and increased speech, motivation, and sensory/cognitive awareness. Although the study showed subjects decreasing in symptoms of Autism, the lack of a control group means that the improvement could be a consequence merely of increased pressure rather than oxygen stimulation of brain tissue. The parents could still be providing data that is biased because they were not blinded to the type of therapy their child was receiving. The 2007 Rossignol study left the door open for a double-blind, randomized study with greater validity.

        In March of 2009, that randomized, double-blind controlled trial was published and supplied the only substantial evidence for the successful hyperbaric treatment for Autism to date. Sixty-two children ages 2-7 were randomly assigned to the treatment or control group (Rossignol 2009). The treatment group received one hour of 1.3 atm per session while the control group was exposed to 1.1 atm to simulate pressure and gradually brought down to 1.03 atm to create the illusion of treatment. The study was double-blind to everyone except the hyperbaric technician, however, he or she did was not involved in analyzing any data. Participants were forbidden to begin new therapies or stop existing ones for the duration. Both parents and the treating physician rated the outcome with the ABC, ATEC, and CGI scales to minimize bias. While 20% of the children in the treatment group had a “no change” rating, 30% had a “very much improved” or “much improved” rating. Compared to the control group, children treated with HBOT demonstrated improved social interaction, eye contact, and receptive language. The results showed that children over age 5 exhibited greater progress than those 5 and under in irritability and social withdrawal. The difference in effectiveness on age is due to the fact that older children with autism usually have a greater deficiency of oxygen when compared to younger children. No significant difference was found between levels of Autism severity, making the treatment applicable to a wide range of individuals.

Is hyperbaric oxygen therapy right for my child?

        As the variability in the results of the randomized clinical trial demonstrates, HBOT could potentially help some children and have no effect on others. Like most other treatments for children with Autism, hyperbaric therapy may not be right for everyone. It certainly is not right for any child with a history of seizures, claustrophobia, or asthma. It would be wise to await the approval of the FDA before trying the new procedure, especially before the long-term effects are understood. However, if Rossignol’s (2009) results are applicable to individuals outside of the study, some children with Autism may achieve improvements in communication and social interaction symptoms.

















Autism Spectrum Disorders (ASDs). (2009). Retrieved September 26, 2009, from Center for Disease Control and Prevention Web site:


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Field, Brain. (2009). Mainstreaming hyperbaric oxygen therapy for autism. Retrieved September 26, 2009, from Web site:


ICDRC Board Members. Retrieved 4 October 2009. From IDCRC Web site:


Lite, Jordan. (2009). Can hyperbaric oxygen therapy help autistic kids? Retrieved September 26, 2009, from Scientific American Web site:


Rossignol, Daniel A. and Rossignol, Lanier W. (2006). Hyperbaric oxygen therapy may improve symptoms in autistic children. Medical Hypotheses, 67, 216-228.


Rossignol, Daniel A. et al. (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. doi: 10.1186/1471-2431-7-36


Rossignol, Daniel A. et al. (2009). Hyperbaric treatment for children with autism: a multicenter, randomized, double-blind, controlled trial. BMC Pediatrics, 9:21. doi: 10.1186/1471-2431-9-21




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