"I think the biggest drain would be a financial drain," said Dr. Paul Offit, chief of the section on infectious disease at the Children's Hospital of Philadelphia and author of "Autism's False Prophets," a book that chronicles some of the dangerous treatments parents of autistic children have tried.
Offit noted that parents of autistic children have been known to take out second mortgages in order to buy hyperbaric chambers, so the therapy, which remains unproved, presents a risk to a family's financial health.
"One should make certain that you get it right," he said.
Dr. L. Eugene Arnold, interim director of the Nisonger Center for developmental disabilities at Ohio State University, echoed those sentiments.
He said that because of the "expense and difficulty of 40 treatments in a hyperbaric chamber [it will] require more evidence before it could be recommended as a standard treatment."
Recent news accounts have placed the cost of hyperbaric treatment at $100 to $900 per treatment at a center. Children in the recent study received 40 treatments.
While he remains skeptical, Offit said the treatment does merit further research.
"It would be of value for the study to be repeated by an academic group that doesn't have a financial desire to see it work," he said. "I think it's good, certainly, that there was an attempt to do this study in a prospective, placebo-controlled way."
Offit also said, however, that some changes would need to be made in a future study, as certain factors may have biased the results of this one. The main problem he cited was observer bias; since parents were sometimes present in the hyperbaric chamber with their children, they were likely aware of whether or not their children received increased pressure, and this may have affected their impression of their child's progress.
"I just think it was a lost opportunity," said Offit. "I don't think it really matters who funds the study. What matters is the strength of the data."
Another problem some doctors had with the study was the theory behind why, exactly, treatment in a bariatric chamber might help. Since the cause of autism remains unknown, there are doubts whether any one specific therapy could help.
Researchers speculate in the paper that the oxygen flow to the brain is reduced in autistic children, a condition known as cerebral hypoperfusion, and the hyperbaric chamber is able to reverse that.
"This is purely speculative and not really supported by the references they cite. The authors appear to be 'stretching' the contents of the references beyond the original intent," Wiznitzer said.
Offit added that he, too, is skeptical of that idea because autism has been shown to affect specific areas of the brain, but if cerebral hypoperfusion was the problem it should be affecting the entire brain rather than specific regions.
Ultimately, more study will be needed to make any recommendations on hyperbaric therapy for autism. In the meantime, any parents seeking to try it may not have to worry about its effect on their child's health but will need to worry about their finances.
"This treatment has no apparent negative effects except for the cost [of out-of-pocket payments]," said Wiznitzer. "I tell parents that use of complementary and alternative treatments can be explored as long as there is no significant risk of injury, it does not interfere with other interventions, it is affordable and it has a defined endpoint."