Rossignol suggests that HBOT compensates for decreased blood flow by increasing oxygen content of plasma and body tissues. HBOT has potent anti-inflammatory effects and reduces oxidative stress. HBOT mobilizes stem cells from human bone marrow, which may aid symptoms in autistic children. Rossignol also provided trial studies with both high and low pressure HBOT and showed promising result and no adverse effects noted. Reference: Rossignol D. Hyperbaric oxygen therapy may improve symptoms in autistic children, Medical Hypotheses 2006, 67:216-228. Rossignol et al. The effects of hyperbaric oxygen therapy on oxidative stress, inflammation, and symptoms in children with autism: an open-label pilot study, BMC Pediatrics 2007, 7:3.

Hard chamber:
· Pros: high pressure and is good for some difficult cases that require high pressure and high oxygen level
· Cons: high risk, high cost and hard to find
Soft chamber:
· Pros: low risk, low cost and is good for most conditions
· Cons: lower pressure and less oxygen concentration

Comparing to other therapies, side effect of HBOT is minimal. The most common complaint is the ear and sinus problems caused by pressure changes, similar to when you travel with airplane. This problem is temporary and resolves when HBOT is completed. To prevent the ear problem, the patients can be taught autoinflationary techniques before the therapy to promote adequate clearing of the ears during treatment. Some patients experience temporary changes in eyesight. These are minor and occur only in those individuals who have large numbers of treatment. Vision usually returns to normal within weeks following the end of treatment. Other side effects such as claustrophobia and oxygen toxicity (when 100% oxygen is used with hood/mask) are rare. With low pressure HBOT, patients usually do not breathe in 100% oxygen with mask, the oxygen related side effect can be easily prevented.