Inclusion Criteria1. Age between 19 and 85.
2. Able to speak English and give informed consent or have a substitute decision maker and able to assent.
3. One or more ischemic stroke(s) involving the cerebral cortex or cerebellum within the last 6 to 36 months
4. Able to sit in the chamber with the assistance of a waist and chest strap for 120 minutes.
Exclusion Criteria1. Contraindication to HBOT (Appendix C) including:
1. Untreated collapsed lung (pneumothorax)
2. Have taken the chemotherapy drug Doxorubicin within 72 hours
3. Have taken the chemotherapy drug Bleomycin within 4 months
4. Bowel obstruction
5. Heart pacemaker of unknown make and model
7. Cigarette Smoking
8. Chronic Obstructive Pulmonary Disease (COPD)
2. Participation in other stroke related studies.
3. Previous history stroke > 36 months prior to study baseline