March 14, 2005, was a day like any other for William, a 38-year-old member of the British Armed Forces stationed in Germany. He got up, went to the gym, played volleyball, and answered emails from his office. By 2:40pm, he was sitting in a dentist’s chair for a root canal. And that’s essentially where he’s been ever since—at least in his mind, reports the BBC. Diagnosed with anterograde amnesia—a condition that keeps him from forming new memories and learning procedural skills—the father of two can’t remember anything for longer than 90 minutes and begins every day believing it's March 14, 2005. Now when he wakes, he reads a detailed note on his phone, titled "First thing—read this," and attempts to grasp all that has happened over the last decade. Unlike patients who've suffered similar fates after surgery, William's brain is undamaged. "We do not know what to make of it," a researcher tells Medical Daily.
Doctors don’t think his case is linked to psychological stress either. Though the Gulf War vet had just lost his grandfather, he had no history of mental illness. Plus, psychogenic memory loss usually keeps patients from recollecting painful memories, not from creating new ones. In William's case, "it's as if the memories are being written in sand. Every hour and a half the tide comes up and washes them away," reports the Washington Post. The best explanation has to do with the consolidation of memories, the process of shipping events to long-term storage. It requires restructuring synapses, and the change takes about 90 minutes. Doctors say this might explain five other cases of anterograde amnesia found in patients who had a medical emergency. They may even carry a genetic predisposition. But why did a root canal perhaps trigger it? "That's the million-pound question," says a researcher, "and I don’t have an answer." (Read about another medical mystery involving one family' four kids.)