Psychologists have encountered a strange case - someone who can remember in exquisite detail almost everything that happened to her. Dubbed "AJ", the patient first called for help a few years ago: "since I was eleven I have had this unbelievable ability to recall my past," she wrote. She's now 36.

This is no gift, but more of a curse, as she describes the burden all these unsolicited memories - "non-stop, uncontrollable and totally exhausting". Neuroscientist James McGaugh of the University of California called this case of memory dominating one's life "hyperthymestic syndrome", from the Greek, meaning excessive remembering.

McGaugh and his colleagues conducted several tests to determine how well she can really remember things. On one meeting for example they have asked her, without prior warning, to remember the dates of the previous 24 Easters. She managed to remember them, as well as all that she did in each day, and she only got one date wrong, being two days off. The scientists poped the same quiz two years later: she said the exact same things, except that this time she got all the dates correctly.

"She sort of has a vacuum cleaner sucking up all of the personal experiences and storing them away so that they're available", said McGaugh.

They have also conducted various formal standard tests such as an autobiographical memory test, an IQ test and autism tests. She scored perfect on the autobiographical test, average on the IQ test and showed some signs of autism. There are already known some cases of autistic individuals whose obsessive-compulsive disorder is directed toward their own person and who are capable of recall abilities similar to AJ's.

However, AJ's condition doesn't seem to be that of a typical autistic. For one thing, no autistic has ever searched for help. Moreover, unlike autistics, AJ doesn't seem to remember things using mnemonic strategies. She explained her ability by saying "I just know it".

Other scientists are still skeptical that AJ is really that different from a standard autistic. For example, cognitive neuropsychologist Stephen Christman of the University of Toledo in Ohio has said that AJ's condition might be simply the result of an obsessive focusing over her memories for hours every day, over and over again.

In order to shed more light on the matter researchers plan to use brain scans to see whether her brain really functions in some unusual way.