Oxidative stress might be simply understood as damage to body cells due to oxidation, a process whereby elements react with oxygen. Burning and rusting are common, everyday examples of what might happen when reaction with oxygen takes place. Of course, body cells do not burn or turn rusty. But they do get damaged by reaction with oxygen and these damaged cells are called “free radicals”. In adults, cell damage is associated with premature aging and with degenerative diseases like hardening of the arteries and cancer.
In children, researchers have commonly observed that children with autism have much higher levels of oxidative stress compared with others. This is one reason why anti-oxidant supplements, such as vitamins A, C and E, are beneficial for children with autism, since such supplements limit the extent of oxygen damage. Given the possibility of oxygen damage, it might seem strange that children with autism are increasingly being recommended hyperbaric oxygen therapy (HBOT).
This process introduces more oxygen into the blood, and hence into the brain, by placing the person in a high pressure chamber enriched with oxygen. Wouldn’t this lead to greater oxidative stress? Wouldn’t it worsen the condition of a child with autism? Experience with HBOT treatment suggests that it does not happen. And the latest scientific evidence confirms this. It further shows that HBOT reduces inflammation — another condition commonly observed in children with autism. And, parents reported that the children’s behavior improved.
Research Studies
The effects of hyperbaric oxygen therapy on oxidative stress, inflammation, and symptoms in children with autism:
an open-label pilot study
Daniel A Rossignol, Lanier W Rossignol, S Jill James, Stepan Melnyk, and Elizabeth Mumper
BMC Pediatrics 2007; 7: 36.
Published online 2007 November 16.
doi: 10.1186/1471-2431-7-36.
Background: Recently, hyperbaric oxygen therapy (HBOT) has increased in popularity as a treatment for autism. Numerous studies document oxidative stress and inflammation in individuals with autism; both of these conditions have demonstrated improvement with HBOT, along with enhancement of neurological function and cognitive performance. In this study, children with autism were treated with HBOT at atmospheric pressures and oxygen concentrations in current use for this condition. Changes in markers of oxidative stress and inflammation were measured. The children were evaluated to determine clinical effects and safety.
Methods: Eighteen children with autism, ages 3–16 years, underwent 40 hyperbaric sessions of 45 minutes duration each at either 1.5 atmospheres (atm) and 100 percent oxygen, or at 1.3 atm and 24 percent oxygen. Measurements of C-reactive protein (CRP) and markers of oxidative stress, including plasma oxidized glutathione (GSSG), were assessed by fasting blood draws collected before and after the 40 treatments. Changes in clinical symptoms, as rated by parents, were also assessed. The children were closely monitored for potential adverse effects.
Results: At the endpoint of 40 hyperbaric sessions, neither group demonstrated statistically significant changes in mean plasma GSSG levels, indicating intracellular oxidative stress appears unaffected by either regimen. A trend towards improvement in mean CRP was present in both groups; the largest improvements were observed in children with initially higher elevations in CRP. When all 18 children were pooled, a significant improvement in CRP was found (p = 0.021). Pre- and post-parental observations indicated statistically significant improvements in both groups, including motivation, speech, and cognitive awareness (p < 0.05). No major adverse events were observed.
Conclusion: In this prospective pilot study of children with autism, HBOT at a maximum pressure of 1.5 atm with up to 100 percent oxygen was safe and well tolerated. HBOT did not appreciably worsen oxidative stress and significantly decreased inflammation as measured by CRP levels. Parental observations support anecdotal accounts of improvement in several domains of autism. However, since this was an open-label study, definitive statements regarding the efficacy of HBOT for the treatment of individuals with autism must await results from double-blind, controlled trials.
Lay Summary: The researchers found that HBOT treatment does not worsen oxidative stress. It also reduces inflammation and improves the behavior of autistic children, although the researchers feel that more research is needed to confirm this.
Comments by John Yeo
HBOT is relatively new in the treatment of children with autism, having grown in popularity only in recent years. However, it has long been acknowledged to be beneficial in the treatment of cerebral palsy or brain damage. And as autism might also be considered a form of brain damage, there are good reasons to believe that HBOT can be helpful. Experiences with HBOT treatment — including my personal experiences with my autistic teenage daughter as well as with many autistic children at the Autism Recovery Centre — have largely been positive.
As the effects of HBOT treatment are not yet fully understood, there are naturally some concerns as well as criticisms. However, as HBOT grows in popularity as one of many treatments in the biomedical approach to autism, more research will be done, leading to better understanding.
