Reporter: Liz Hayes
Producers: Phil Goyen
Imagine waking up one morning and you've forgotten everything about yourself.
You don't recognise your face, you don't know your family, you can't even remember your own name. Well that's what happened to Nicole Caird and Claire Robertson.
Every few minutes their minds wipe clean, stealing every scrap of memory, from the birth of their children to the reason they're sitting in front of a television camera.
And what is especially alarming is that the culprit is a virus that most of us have lurking in our bodies.
Read Liz Hayes' blog on this story and have your say
For more information on herpes encephalitis
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LIZ HAYES: For the Caird family of Brisbane this holiday last Christmas was the trip of a lifetime. 2.5 weeks in Europe skiing, sightseeing and partying. Do you remember the holiday, Nicole?
NICOLE CAIRD: No, do we?
BRAD CAIRD: Think back. Where did we go?
NICOLE CAIRD: Oh, I don't know.
BRAD CAIRD: Got nothing?
NICOLE CAIRD: No, where?
BRAD CAIRD: Europe.
NICOLE CAIRD: Really? Really?
LIZ HAYES: But it's a holiday Nicole Caird just can't remember, even when her husband Brad plays these home videos.
BRAD CAIRD: And you stopped and you were so excited.
NICOLE CAIRD: Is that me?
BRAD CAIRD: That is you, except for that bit there.
NICOLE CAIRD: When was this?
BRAD CAIRD: At Christmas time. That was Christmas Day, Boxing Day.
NICOLE CAIRD: Huh?
BRAD CAIRD: Boxing Day we did that. Boxing Day last year.
LIZ HAYES: Just over 12 months ago large chunks of Nicole's memory were wiped out after the very common cold sore herpes virus attacked her brain. Unlike Alzheimer's disease, though, Nicole's brain won't deteriorate, but right now even her new memories only last minutes. What is your sense of what's happened to you?
NICOLE CAIRD: Oh, good question. Um, not a lot really. Confusion is what I have. I don't know why and I just can't remember a damn thing.
LIZ HAYES: Are these your children?
NICOLE CAIRD: Ah, well, I think yes. They must be my friend's, my children and their friends.
LIZ HAYES: It's been 6.5 years since Claire Robertson's brain was also hit by the cold sore virus. It wiped her memory too and incredibly all memory of faces, including her own. All these people recognisable?
CLAIRE ROBERTSON: I think that's me. Is it?
LIZ HAYES: It is.
LIZ HAYES: Do you know who this is then?
CLAIRE ROBERTSON: Is that me as well?
LIZ HAYES: Yeah.
CLAIRE ROBERTSON: Gosh.
LIZ HAYES: Claire was just 43 when she lapsed into a coma after suffering what she describes as flu-like symptoms.
LIZ HAYES: You woke up to a new life?
CLAIRE ROBERTSON: Yes. To complete confusion. I didn't know where I was, who I was.
LIZ HAYES: You didn't recognise your family?
CLAIRE ROBERTSON: No.
LIZ HAYES: Your husband?
CLAIRE ROBERTSON: No
LIZ HAYES: Your children?
CLAIRE ROBERTSON: No.
LIZ HAYES: For most of us this is an experience of a lifetime, riding high over London in the city's iconic Eye. But to give you an idea of how dreadful this syndrome is - for most sufferers this would virtually be a waste of time. You see it takes about 30 minutes to complete the journey, so by the time it reaches the bottom, for most sufferers would not only would they have forgotten who they were with, many would have even forgotten taking the ride.
AVA EASTON: We say to people what's happened really is you've sustained an injury to the brain just in the way that you would in a car accident, except you didn't have the car accident.
LIZ HAYES: Ava Easton heads the UK's Encephalitis Society, the world's biggest support group for people like Claire and Nicole.
AVA EASTON: Encephalitis means inflammation of the brain, and in their cases the herpes simplex virus made a direct attack on their brain tissue. The difficulties they're experiencing now is as a result of the injury to the brain that was caused by the virus damaging the nerve cells in the brain.
LIZ HAYES: Claire is married with four children. Before her illness she worked as a nurse. Losing nearly all memory of her life has been devastating.
CLAIRE ROBERTSON: I was able to do and be a nurse and mum and friend and daughter, wife. I was happily doing all these things and the whole loss of that whole feeling of any sense of reality about myself has been awful.
LIZ HAYES: It's quite shocking really, it's like your previous life was erased.
CLAIRE ROBERTSON: I do feel I've been left out of my own life, no sense of belonging to it. It's something that's happened and I don't know about it.
LIZ HAYES: Now I wear a name tag that helps you identify me.
CLAIRE ROBERTSON: : Yes.
LIZ HAYES: For Ed, it's his necklace?
CLAIRE ROBERTSON: It is. yes. His little shark's tooth necklace that he wears all the time. Ed is Claire's husband of more than 20 years.
CLAIRE ROBERTSON: I know now that this is Ed. But if he's away a second later over the other side of the room and there's other people, I don't know who he is at all. But I can see the necklace and I know to be confident and certain that it's him.
LIZ HAYES: People might find that extraordinary, given that you know Claire's your wife and so the face is not the recognisable feature. ED: Just as well. It is extraordinary. It is extraordinary.
LIZ HAYES: How did you start again, because there is this shared history that's gone? ED: There wasn't a way of doing it. We just sort of carried on. There's definitely an element of having to rebuild a relationship with somebody because those things have changed, those shared memories have changed or disappeared. So yeah, you have to rebuild that and we still are.
LIZ HAYES: Friendships also have to be constantly rebuilt. For those, Claire relies on this book. Every friend is listed with a description of how she knows them, just in case they call or drop in. CARER: What are you going to cook for tea tonight, Nicole?
NICOLE CAIRD: I don't know.
LIZ HAYES: Nicole Caird is having to start again too with a carer from Open Minds reminding her how to complete daily chores. A task made all the harder when your memory is constantly being erased.
CARER: Where did we put them yesterday, do you remember?
NICOLE CAIRD: What, the skewers?
NICOLE CAIRD: No. Must be over there.
CARER: Oh goody, found them. Yay.
LIZ HAYES: Can you cook?
NICOLE CAIRD: To be honest, I don't think I've tried, I used to but I don't...
BRAD CAIRD: You have tried.
NICOLE CAIRD: Have I, have I? Can I?
LIZ HAYES: Nicole desperately relies upon Brad to fill in the blanks, a memory loss that includes many significant events.
LIZ HAYES: Do you remember getting married?
NICOLE CAIRD: I know that I am married but I can't create a visual, if that what you, yeah.
LIZ HAYES: Do you remember your children being born?
NICOLE CAIRD: I know that I've got children and I can picture them, but, again, I can't visualise the day of the event, if that makes sense.
LIZ HAYES: You don't remember giving birth?
NICOLE CAIRD: No, no.
LIZ HAYES: When you look at your mum, what do you feel?
JESSICA CAIRD: I guess, sadness, because she's not there anywhere. Like she looks the same but she's just not there inside.
LIZ HAYES: 14-year-old Jessica is struggling with losing the mother she knew. Do you feel like you've lost the connection with your mum?
JESSICA CAIRD: Yeah, because she doesn't really remember what the connection was or if we had one, but, yeah, it's definitely, it's there like very far in the distance but yeah, it's definitely lost.
LIZ HAYES: If there was one memory you'd like to have back, what would it be?
NICOLE CAIRD: That'd be the girls as babies.
LIZ HAYES: Those big events.
NICOLE CAIRD: And their first steps and, yeah, then as they're growing up. Their first day at school and first riding the bike, their first game of football. Just things like that.
LIZ HAYES: 40 minutes into our interview it was clear Nicole was also unsure why I was talking to her. Have you forgotten us?
NICOLE CAIRD: I've forgotten who you are but I know I've forgotten your names but I know you're from a known place, if that makes sense. Where are they from?
LIZ HAYES: 60 Minutes.
NICOLE CAIRD: Oh, 60 Minutes. Wow!
LIZ HAYES: I experienced the same moment in London. In the few minutes I'd stepped away from Claire Robertson and her friend, she too had forgotten me. You remember who I am, don't you?
CLAIRE ROBERTSON: No, sorry.
LIZ HAYES: But this time its very possible that when Claire gets home, she will remember. This small camera she wears around her neck is recording her every move.
CLAIRE ROBERTSON: There's memories in there.
LIZ HAYES: It's unlocking them.
CLAIRE ROBERTSON: Yes.
LIZ HAYES: That's it.
CLAIRE ROBERTSON: Yeah. Which is what this is so good at.
LIZ HAYES: The SenseCam, as its known, has recorded her day with us. It's technology researchers believe can trigger memories. Every 20 seconds it captures a picture, which Claire downloads at the end of the day. You can rewind the day?
CLAIRE ROBERTSON: Yes. Rewind the day.
LIZ HAYES: It's not going to be a cure is it, but it can really make a difference.
CLAIRE ROBERTSON: Yes. It has helped me hugely. I can now think through, visualise days and events that I've done, that I've seen over and over again on the SenseCam computer. The strong feeling is a sense of security. They're mine, the memories are my own. They belong to me and I've got them.
LIZ HAYES: And it's this scan of Claire's brain that makes researchers believe it works. This is Claire's brain when trying to remember things that haven't been recorded by the SenseCam. Compared to this, her brain literally lights up when remembering events she has seen on the SenseCam.
AVA EASTON: It's absolutely amazing, and it makes significant difference in people's lives. And over periods of time, that revisiting the images with the SenseCam actually to some degree enable them to relive those moments in a way that just writing notes, handwritten notes, doesn't allow you to do.
LIZ HAYES: It's the research Nicole and her family need to hear. They're still trying to pick up the pieces, left by an illness that seems very cruel indeed. What are your dreams, what are you hoping for?
NICOLE CAIRD: Just to be the person that I was.
LIZ HAYES: Do you think that can be?
NICOLE CAIRD: I hope so. But Nicole can take heart from people like Claire. Six years on, Claire has made real progress and there are now signs that not everything has been lost.
LIZ HAYES: Have you been able to reconnect with your family?
CLAIRE ROBERTSON: Yes.
LIZ HAYES: And your husband?
CLAIRE ROBERTSON: Yes, yes. I've had a sort of more real recent, occasional feelings of a real sense of belonging. It was only last week I think I remembered, now I've forgotten what it was, but remembered something that he used to, that made him happy. Now I remember the warmth the whole feeling of security, lovely feeling, that's me and Ed.