A father-of-two has been left with a 10-minute memory after suffering a cardiac arrest - where the heart stops pumping blood around the body - more than 12 years ago.
At the time, John Mills was 47 years old.
He collapsed and his brain became staved of oxygen. Now he can only remember things for 10 minutes before they are forgotten completely.
He told ITN: “Everything seems perfectly normal, obviously it isn’t.”
John’s wife, Jackie, explained: “People who have been without oxygen for half an hour, a lot of them are dead. Some of them are absolutely fine.
“And there’s a sliding scale in between of various degrees of brain damage.”
John sits somewhere in the latter camp.
Rebecca Pierce from Headway Cardiff said for people with brain injuries, not having those memories from your past can rob you off your sense of identity.
She explained: “People who have problems remembering what’s happened to them before they’ve had their brain injury or have problems forming new memories, they’re kind of robbed of that constant, personal photo album and recollection that we have.
“It can rob them of their sense of identity and their history and also their sense of a future.”
Jackie explained that, with John, even the simplest of tasks can prove difficult.
“When he had a bath, I went in and washed his hair, put the shampoo down on the side of the bath and said, ‘right I’m just in the bedroom, just give us a shout’,” she said.
“Five minutes later I wandered in and there he was washing his hair and I said, ‘oh I’ve already done that my love, hang on let me just put the shampoo on the side and rinse it off, you carry on now’.
“I went in the bedroom, then five minutes later he was washing his hair again.”
She added that they have had to learn strategies to cope with John’s severe lack of memory and said they aren’t like a couple anymore.
She said: “It’s more like looking after a two-year-old.”