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LEICESTER, UK: In March 2005, a 38-year-old British soldier stationed in Germany lost his ability to form new memories after undergoing a regular root canal treatment. To this day, he is unable to remember anything for longer than 90 minutes, although his brain is completely intact and he suffered no trauma that could have caused the amnesia, according to his doctors.
“I remember getting into the chair and the dentist inserting the local anaesthetic,” the man, who wishes to remain anonymous, told the BBC. Since that moment, he remembers nothing. Every morning, he wakes up thinking that he is still a soldier stationed in Germany in 2005, waiting to visit the dentist for root canal surgery.
The German dentist only realised after the treatment, which was without complications, that something was wrong with the patient. He was pale, disoriented and struggled to stand up. As his condition did not improve, he was brought to hospital where he stayed for several days. In the beginning, he was not able to remember anything for longer than a few minutes.
The doctors’ first suspicion was that a bad reaction to the anaesthetic had caused a brain haemorrhage. However, they could not find any evidence of injury. Finally, the patient and his family returned to England, where Dr Gerald Burgess, a clinical psychologist from Leicester, took over the case.
According to Burgess, a form of anterograde amnesia would have been the most obvious explanation for the man’s condition. In this case, the hippocampi, the brain regions responsible for the consolidation of information from short-term memory to long-term memory, are damaged so that memories can no longer be formed and stored correctly. Yet, the man’s brain scans showed no abnormalities. Thus, another possible explanation would have been a psychogenic illness. Burgess conducted detailed psychiatric assessments in order to determine whether the man had suffered any trauma. However, Burgess found that his patient was emotionally healthy and his wife confirmed that there had not been any traumatic events in the man’s life prior to his dentist visit in 2005.
Burgess continues to research his patient’s rare case of amnesia, currently suspecting that the brain’s synapses might play an important role. Each time a memory is formed and transferred to long-term memory, the synapses are rebuilt, which involves the production of new proteins. This protein synthesis might be blocked in the case of Burgess’ patient, keeping him from generating any new long-term memories. In order to further research his hypothesis, Burgess is examining five similar cases of mysterious memory loss without brain damage from the medical literature. These cases might provide an answer to why the root canal treatment appears to have triggered the man’s memory loss. All of the cases are in some way related to a period of psychological stress during a medical emergency. “It could be a genetic predisposition that needs a catalyst event to start the process,” Burgess told the BBC.
“One of our reasons for writing up this individual’s case was that we had never seen anything like this before in our assessment clinics, and we do not know what to make of it, but felt an honest reporting of the facts as we assessed them was warranted, that perhaps there will be other cases, or people who know more than we do about what might have caused the patient’s amnesia,” Burgess stated.
The case report by Burgess, titled “Profound anterograde amnesia following routine anesthetic and dental procedure: A new classification of amnesia characterized by intermediate-to-late-stage consolidation failure?”, was published online in the Neurocase journal on 15 May.
