Inclusion Criteria:

• Male and female children, ages 3 to 8 years with a diagnosis of spastic cerebral palsy.
• No documented evidence of hypoxic-ischemic encephalopathy (HIE). Hypoxic-ischemic encephalopathy (HIE) is not one of the major causes of CP.
• Medically cleared to participate. Your child's primary care physician will be asked to medically clear your child before entering the study.
• Able to pass pretest screening exercise. Each child will undergo the following screening exercise to determine the likelihood of being able to participate in the study: In order to assess ability to tolerate the placement of the oxygen hood in the hyperbaric setting, a hyperbaric oxygen hood will be placed upon the shoulders, or body of your child (depending upon size of your child) and with encouragement and comforting by you and study nurse, the child will be asked to maintain the placement of the hood for 15 minutes. Each child will be asked to blow through a straw, blow the nose, drink through a straw, or to swallow on command.

Exclusion Criteria:

• Any previous HBO treatments.
• Thoracic surgery within 6 months of beginning the study.
• Unstable epilepsy as determined by a history of having had more than one major motor (generalized or partial tonic/clonic) seizure within the past six months. Having multiple motor seizures, requiring more than three anticonvulsant drugs for seizure control; or requiring changes in seizure medications more than once per month.
• Significant pulmonary dysfunction as determined by a history of chronic pulmonary disease, cystic fibrosis, interstitial lung disease, or chronic shortness of breath or cough. Uncontrolled asthma/reactive airway disease.
• Significant behavioral problems requiring medication.
• Any major congenital deformities of the brain or spinal cord.
• Active pneumothorax (collapsed lung).
• Recent cancer treatment with cisplatinum, bleomycin, or doxorubicin.
• Certain heart problems that cause the heart to pump poorly as determined by a history of congenital heart disease, cardiomyopathy, or symptoms of chest pain, dizziness, and shortness of breath.
• Optic neuritis.
• Diabetics requiring insulin therapy.
• Spherocytosis.
• Major GI reflux with frequent emesis.
• Botulinum toxin A (Botox) treatments within 6 months of entering study.
• Before entering the study, we will require that chronic medications be unchanged for the prior three months except for minor dosage adjustments.