Kids with autism may benefit from a series of treatments in a pressurized chamber with boosted oxygen levels.

The results of small trial indicate that hyperbaric oxygen therapy, as it's called, improves language ability, social interaction, and other functions in such children.

The trial involved 62 children, from 2 to 7 years of age, diagnosed with autistic disorder. Dr. Daniel A. Rossignol, from the International Child Development Resource Center in Melbourne, Florida, and colleagues, randomly assigned the children to 40 one-hour sessions of hyperbaric therapy or sham treatment.

The hyperbaric group was treated with 24 percent oxygen at a pressure of 1.3 atmospheres while the comparison group received a normal level of oxygen (21 percent) in a slightly pressured room (1.03 atmospheres). To be safe, the active treatment was actually a relatively low level of hyperbaric therapy; treatment for carbon monoxide poisoning, for instances, is usually given at 2 atmospheres with 100 percent oxygen.

The team found that, compared with the sham treatment, hyperbaric therapy significantly improved the kids' overall functioning, grasp of language, social interaction, and eye contact.

Moreover, 80 percent of hyperbaric-treated patients were rated as improved compared with 38 percent of controls, according to the report in the online journal BMC Pediatrics.

On a behavior checklist, the hyperbaric treatment group had significant improvements in irritability, hyperactivity, repetitive behaviors, and speech, while the control group did not.

Further analysis of the results showed that children who were at least 5 years old and those with lower initial autism severity derived the greatest benefits from hyperbaric treatment.

No treatment complications were noted with hyperbaric therapy, which was well tolerated.

"Given the positive findings of this study, and the shortage of proven treatments for individuals with autism, parents who pursue hyperbaric treatment for their child with autism can be assured that it is a safe treatment modality at the pressure used in this study, and that it may improve certain autistic behaviors," Rossignol's team concludes.