Routine Dentist Visit Leaves Man With 90-Minute Memory,Baffles Doctors

Doctors are searching for answers in an effort to help a 48-year-old man who was left a routinedental visit with a memory span of 90 minutes, turning him into a real-life version of the amnesiaccharacter in the groundbreaking 2000 movie "Memento."

The patient, identified only as a member of the U.K. military at the time, wakes up every daythinking it's the day of the dental appointment, researchers said, noting that thehttp://kuzmetsovob.livejournal.com/2555.html patient was stationed in Berlin when he went to thedentist for a routine root canal in March 2005.

After the procedure, the patient was pale and faint with "slow speech" and appearing "vacant,"according to the case study published in the journal Neurocase. While being treated at a hospital,medical staff found he could only remember 10 minutes at a time, researchers said, noting he nowcan remember up to 90 minutes at a time.

"I remember getting into the chair and the dentist inserting the local anesthetic," the patient toldBBC News of what he remembered about the experience.

During the procedure, the patient, then 38, was given routine anesthesia, but clinical psychologistDr. Gerald Burgess, who now treats the man, doesn't think the cause of his memory loss is only theresult of that common procedure.

"I think we learned so much, assessing and working with the patient," Burgess told researchers forthe case study. "One thing is that we should perhaps not be so stuck in thinking that profoundamnesia only occurs in the context of visible damage to the brain's ... structures."

'We had never seen anything like it before.'

There's a chance that a neuro-chemical or neuro-electrical event occurred, Burgess said, and that itmay have permanently impacted how memories are stored and formed. Burgess is now asking theglobal medical community for help in identifying similar cases in the hopes of finding out why thishappened to the patient.

"We had never seen anything like this before in our assessment clinics, and we do not know what tomake of it," Burgess said. "We had never seen anything like it before."

Dr. Eugene Wesley Ely, of the Vanderbilt ICU Delirium and Cognitive Impairment Study Group, haslooked at how potent sedation can impair long-term memory function even years after sedationoccurred.

"Those memory problems can mimic a dementia like illness that might [appear] like Alzheimer's orTraumatic Brian Injury Disease," Ely, who was not involved with the patient's care, told ABC News.However, he said that a simple root canal leading to long-term memory problems is an "outlier."

'Every day he thinks it is the day of the dental appointment.'

Dr. Jacopo Annese, director of the nonprofit Brain Observatory, has studied the brain of anotherfamous amnesic, Henry Molaison, who could retain almost no new information after epilepsysurgery. Annese told ABC News he was surprised that there was no visible structural damage.

"It's fascinating, but it's a mystery and it's very humbling because when something like this happensyou realize we don't yet have technology to inquire directly into human brain," Annese said.

The U.K. patient's brain scans, including MRI and CT scans, appeared normal, according to the casestudy. While the patient's short-term memory has been severely impaired, he has been able tolargely adapt to his condition according to Burgess. The patient, along with his family, moved backto his family home in the U.K., which he remembered from his childhood. He uses GPS to get aroundthe neighborhood, though he is always surprised his family is not the same age they were the day ofthe dental appointment, researchers said.

"He wakes up believing that he should still be in the military, stationed abroad," the researchers saidthe in study. "Every day he thinks it is the day of the dental appointment."

To stay updated, he keeps a meticulously updated electronic journal and his wife tells him everymorning to look at a computer with important events from the last decade.

In the movie "Memento," the lead character, played by Guy Pearce, loses his memory every time hegoes to sleep and must reconstruct his life using things such as tattoos on his own body.

According to the case study, the patient can grasp that he has lost his memory after it is explained tohim.

"He may say, 'I know I have a memory problem,' or 'I think it is March 2005, but it is not,'" the studyauthors said.