Going to the dentist is an unpleasant experience for many, but for one man a routine visit turned into a medical mystery.
For the past 10 years, a 48-year-old British man known only as William has been waking up every day thinking that it is March 14th, 2005, he's living in Germany, and he has a dentist appointment to get to.
On that day, he underwent a standard root canal during a military deployment overseas. The last thing he remembers is receiving a local anaesthetic before the procedure, after which observers noted that he woke up in a mentally declined state.
Though he is able to recall events prior to that moment, he can only retain new memories for 90 minutes before they are forgotten.
This is an improvement, as he was only able to remember 10 minute periods shortly after the incident occurred.
Doctors still do not know why his brain continues to malfunction, as scans show no signs of damage. One of the theories that has gained traction involves faulty protein synthesis in his memory centre.
William's symptoms are similar to patients suffering from as anterograde amnesia. This is when damage to the bilateral hippocampal or diencephalon regions in the brain cause short spans of awareness and complete and rapid memory loss.