On March 14, 2005 "William O" received an anesthetic for root canal surgery. The next morning when William woke up, he thought it was still March 14 and that he had a dentist appointment. He's had the same impression for the last 3800+ days.
William's doctor, Gerald Burgess from the University of Leicester says:
"He wakes up believing he should still be in the military, stationed abroad.
"Every day he thinks it is the day of the dental appointment.
"Each morning he is prompted by his wife to check his computer, on which the family has listed, and keep updated, key facts he should be aware of.
"Some events that have occurred since the onset of his condition in March 2005 continue to elicit genuine surprise or astonishment."
William is now 38, and he can hold onto new memories for only 90 minutes before losing them. Doctors don't know why William is this way, but one idea is the "cause of amnesia in William could be a breakdown of protein synthesis in the brain."