Terry Prone has described how she lost the memory of a complete day of her life.
The chairman of the Communications Clinic had a busy day last Tuesday - including giving a four-hour training course and speaking to Newstalk's own Pat Kenny live on-air with a Budget 2022 preview.
However, she now has no memory of those events taking place, although she has been able to piece together what happened that day with the help of those around her.
Doctors have since put the incident down to a sudden and temporary episode of memory loss known as transient global amnesia.
Almost a week on from that lost day, Terry spoke to Pat about what happened.
She recalled: “I’m never going to get back that day. I know what happened that day - but that’s because other people have told me.
“I know I went to work very early… I know that I was starting a quite complicated course with six people… I know I set them up with an exercise, and then went down to my own office to go on the landline for you to talk to me at exactly 9:20am. I know all that… but I have no recollection of it.
“I went back to the training room and did four hours of training. The head of training in our place - Lorcan Nyhan - was sitting in, and he said I did a perfectly ordinary and creditable course."
The first hint that something was wrong happened when the course finished up.
Terry was sitting in the training room when training coordinator Ellen came into the room. Ellen started tidying up, but then Terry asked why there were empty cups of coffee lying around the room.
She said: “Ellen thought that was kind of strange, because I had just run the course. She answered me… and 30 seconds later I asked her the same question again.
“When I asked a third time, she answered me, left the room and went up and got Lorcan. When Lorcan arrived, I started the same thing: different questions, but repetitive, repetitive, repetitive.
“They decided to send me to a hospital in an ambulance - which I think requires fair courage, to send your chairman to hospital.”
Hospital visit
Terry was taken to St James's Hospital, and it was clear she couldn't remember things around 30 seconds after they happened.
Over the course of the afternoon and evening, her memory started improving - to 10 minutes, then longer again.
Meanwhile, doctors started doing tests - initially believing the most likely cause was viral encephalitis - and Terry was admitted to the ward while they worked to get to the bottom of what happened.
The day after the memory loss episode involved lots of scans and tests, with both the infectious diseases and neurological teams on hand.
Terry said it was quite "unnerving" doing some of the tests, as she wanted to prove she was OK.
There was a major "sense of relief" when she returned a good result from some of the more intensive neurological tests.
However, it still wasn't clear what had happened, so an epilepsy expert was brought in to see if maybe a seizure had caused the memory loss.
Terry said the expert called Ellen to hear her account of what had happened that day.
She recalled: “He was asking very precise questions about what she had observed.
"When he handed me back the phone, he said ‘well that blows my thesis - you didn’t have a seizure’".
Transient global amnesia
Ultimately, the conclusion was that Terry had had an episode of transient global amnesia rather than an infection or seizure.
As described by the Mayo Clinic, transient global amnesia is a "sudden, temporary episode of memory loss that can't be attributed to a more common neurological condition".
Terry explained: "It’s one of these things that’s as random as being hit by a meteorite.
“The only two associated factors seem to be number one that you’re over 50, and that number that it has some link - not necessarily causative - with migraine.
"Since I had a car crash around 30 years ago, I’ve had this odd thing where I get a migraine aura - meaning a visual distortion. You can’t work or read or anything when you have it.
"The best thing of all is that transient global amnesia doesn’t come back... it seems to be for the most part a once-off visitor.”
Terry says she made it through the whole episode without being particularly agitated or alarmed about what was happening - although noted she had "no clue while it was happening".
She said she would be "really frightened" if it happens again - but said she's reassured by the medical evidence that it's a condition that "rarely comes back for another visit".
