The purpose of this study is to examine whether 40 hyperbaric oxygen sessions has effect on
long-term symptoms after brain injury. This study will enroll 90 individuals with persistent
problems 6 months to 10 years after a brain injury. These individuals will be randomized to
receive either oxygen or air in a pressurized hyperbaric chamber. Participants will receive
40 daily hyperbaric chamber sessions.

Participants will have a series of tests and questionnaires before they begin their chamber
sessions, after they complete 40 sessions, and 6 months after they joined the study. These
tests include computer-based and pencil-and-paper questionnaires and thinking tests, brain
imaging, a neurological examination, and an eye exam. Participants will also be asked to
provide blood for future research.

After the 6-month tests are complete, all participants will receive 40 hyperbaric oxygen
sessions, then undergo the same tests at 9 months and 12 months.