The 1993 movie Groundhog Day is a comedy classic in which a beleaguered Bill Murray is forced to relive the same day again and again with increasingly hilarious results, and now an ex-army man from Britain is experiencing something very similar: he wakes up every morning believing it's 14 March 2005, and he has a trip to the dentist scheduled for later that day.
The man - who hasn't been identified for reasons of family privacy - is the subject of a new case study by academics at the University of Leicester. There are no medical breakthroughs to report here, but clinical psychologist Gerald Burgess says he wanted to put the incredible situation on record in the hope of finding more comparable cases across the world.
"We had never seen anything like this before in our assessment clinics, and we do not know what to make of it," says Burgess. "Our experience was that none of our colleagues in neurology, psychiatry, and clinical neuropsychology could explain this case, or had seen anything like it themselves before."
The unfortunate 38-year-old man began experiencing acute memory loss after receiving local anaesthetic and root-canal treatment at his dentist. For the last 10 years he has been unable to keep memories for longer than 90 minutes, and he wakes up every morning believing he's back in Germany in mid-March, with a dentist appointment coming up later that day.
What's been baffling psychologists is that there's no sign of damage in the man's brain and no obvious signs that the dental treatment caused the issue. His personality and long-term memory have not been affected, but he can't create new memories, and now lives his life with the help of prompts on a smartphone and reminders from friends and family.
The type of brain injury scientists would expect to see with this kind of memory loss - damage to the hippocampal and diencephalon structures that act as a 'printing press' for new memories - just isn't there. Ultimately, the man's condition may change the way we think about problems with memory and brain function, if researchers can work out exactly what is going wrong.
One theory is that something is happening to the memories right before they're written to the hippocampus for long-term storage - something's wiping them out deep in the neural synapses that are supposed to consolidate themselves to store memories. Burgess says there's a lot more work to do to back up the theory, and he's encouraging other researchers to get in touch with him about similar cases.
As for the man living with the condition in the UK, the one memory he has been able to form in the last decade relates to the death of his father, and that opens up another interesting tangent for researchers regarding the link between emotion and memory. For the rest of us, the next time you wake up dreading a dental appointment, just be grateful you don't have the same feeling every single day.