Inclusion Criteria:  medically free by their doctor. being able to tolerate a hyperbaric oxygen hood. being able to blow through a straw, or swallow on command. having spasticity ranging from 1 to 1+ on the Modified Ashworth Scale level I or II on the Gross Motor Function Classification System (GMFCS). being capable of understanding and following instructions  Exclusion Criteria:  Previous HBO treatments. botulinum toxin A treatments. thoracic surgery within 6 months. major changes to spasticity medications within 3 months. unstable epilepsy. pulmonary dysfunction. cardiovascular disease