Case report of self-initiated HBOT in a 62-year-old man with a clinical diagnosis of probable Alzheimer’s disease. He had over 400 HBOT sessions [2–3 times weekly, with a duration of 30–50 min, in a multi-place hyperbaric chamber at 2 atmospheres absolute (ATA)] over 7 years and use of donepezil (10 mg daily) for the last 3 years when formally diagnosed by the National Health Service (NHS) Memory Service. The patient’s longitudinal neurocognitive and neuroradiological evidence over 7 years of follow-up remained stable (with no major cognitive decline and no behavioral changes)