I am one of 100 people in the world with a condition that allows me to remember the day I was born

Two women have revealed what it’s like to live in an incredible state that allows them to remember what it was like to be babies.

Emily Nash, 18, of Ottawa, Canada, is the youngest known person with a condition that gives her an incredible, photographic memory.

Her brain is “organized like a calendar,” as she puts it, and has the ability to replay, rewind, and fast-forward any significant experience or event.

She claims she vividly remembers learning to walk and her parents chasing her around the house like her.

Becky Sharrock, 34, Australia’s only known case of HSAM, says she remembers the day she was born and the “intense curiosity” she felt as a newborn.

High-grade autobiographical memory, or HSAM, affects only about 100 people in the world.

The condition was only discovered in 2000 and is still poorly understood.

For most people, the brain stores only 50 percent of new information within an hour of learning it, and is constantly clearing storage to make more room for new memories.

One theory is that in people with HSAM, their the brain may not be able to determine and filter out which information is unimportant, which means they remember almost everything, whether it’s noteworthy or not.

Ms Nash told 60 Minutes Australia: “My brain is almost organized like a calendar. Each date specifically resembles a movie where I can replay, rewind, fast forward. And the more I go into a particular day, the more vivid and the more details I can get out of that day.”

“It’s almost like reliving it, like I was there seconds ago,” she added.

The condition applies not only to experiences, but also to facts. Ms Nash’s parents, Julie and Jason, nicknamed their daughter Wikipedia because of the vast amount of knowledge she remembers.

The family had no idea why she remembered things so well and assumed she was just blessed with an ‘excellent memory’, her mother said.

Mrs. Nash’s first memory is being fed by her mother in a high chair as a baby. She claims to remember learning to walk.

“I remember my parents started chasing me around the house because I was so excited to learn to walk and it turned into running.

“I think I even learned those two things on the same day,” she recalled.

It wasn’t until she was formally tested at age 17 by Dr. Carmen Westerberg, a professor of psychology on Texas State Universitythat they realized the full extent of her abilities.

Her mother Julie said the family was now focusing on making happy memories because Mrs Nash would remember everything.

“From the moment I found out, I had to change my parenting perspective, it will be a lasting memory,” her mother said. “So we sweat the small stuff a little less.

Ms Nash said being able to remember every promise her parents and friends made can be hard on relationships, but she has learned to forgive them and tries not to hold grudges.

Ms Nash has volunteered for science and scientists are studying her brain to hopefully find a cure for debilitating memory loss conditions such as dementia and Alzheimer’s.

They will try to understand exactly what is going on in Mrs. Nash’s brain, so they might be able to find out what goes wrong in the brains of people with Alzheimer’s disease.

“Knowing that I am able to help with my memory is a very rewarding experience,” Ms Nash said.

She is partly motivated by seeing two of her grandparents suffer from dementia.

She is heading to university later this year to study science and memory herself.

The sleep studies she’s already participated in suggest that it’s not a case of Ms. Nash taking in or learning more information than anyone else, but just not forgetting it.

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“While she’s sleeping, her brain stores it more efficiently than other people,” said Dr. Westerberg, who worked on the studies.

“Why is still a big mystery,” she added.

Like Ms Nash, Ms Sharrock said she “pretty much remembers every second of every day”.

“At least I remember about 95 percent of the time.

When she was younger, she said she was ‘so smart it would have embarrassed me as a child’.

Ms. Sharrock even claims to remember the exact day she was born.

“I have one memory that I believe I was born with. I found myself just wrapped in a blanket and then had my ankle cut with a tag.

“Obviously you can’t prove it 100 percent to the skeptics,” she said.

“I had a strong curiosity. As a child, I didn’t know the word curiosity, but I wanted to know everything about everything. I was probably about 5,000 percent more curious than I am now.’

Mrs. Sharrock also has autism, which adds to the sense of chaos that comes with being able to remember everything.

“I get a lot of distractions from random flashbacks that come into my mind, they just come involuntarily,” she said.

There are days she would like to forget, she said.

“I have moments of self-pity where I just wonder why I have to have this state of memory, why I just can’t forget certain things. It’s a curse to have.’

Research has shown that compared to normal people, people with the condition have disrupted connectivity between the hippocampus – a part of the brain that plays a key role in learning and memory – and several networks used in saliency detection – which decide what information is important – while participants were in a resting state.

This means people with HSAM they may not be able to determine which information does not need to be retained, meaning they remember almost everything.

Some researchers believe that HSAM may be a special form of OCD because there are similarities between their brain structure and that of OCD patients.

Both have an enlarged caudate – which is involved in processes such as procedural learning.

There is a link between autobiographical memory and autism because the sensory experience of some individuals with autism helps to embed events deeply in their memory.

Some people with autism also have a memory that is photographic or almost photographic.