What is transient global amnesia

By Keith Howitt,
updated on Nov 12, 2020

What is transient global amnesia

In the midst of the Covid-19 pandemic, and while dealing with a family crisis, Keith’s brain decided to take a short break. When it switched itself back on, he needed to find out what had happened…

I seem to wake with a start. But I’m sure I haven’t been asleep, so I’m confused and scared.

It’s sunny outside, the clock says it’s the middle of the afternoon, and I’m sitting at the kitchen table. And I have absolutely no idea how I got here. Then everything goes blank.

Gradually, like a new scene opening in a movie, my wife and two step-daughters appear around me. I can’t work out what we’re doing. But then the screen fades out again.

The next scene begins, full of action. In the kitchen there are now two men dressed in green uniforms, wearing face masks. They are asking me questions and are attaching electrodes to my chest.

Slowly, things start to make a little sense again. I recognise my family. I remember the dog is called Lilly. I’m asked to write my name on a piece of paper, and I can.

The paramedics say they are taking me to hospital. Because of the pandemic, no one from the family can travel with me so they follow in the car.

In the ambulance, I’m asked lots of questions, and I can answer most of them. Oddly, I feel physically OK.

There remains just one major problem – the missing time, possibly just 15 or 20 minutes, where I have no idea what happened, and no recollection of what I did.

At the hospital everyone is, as expected, amazingly kind and professional. A stream of nurses carry out tests, and a young A&E doctor gives me a thorough once-over.

Keith smiling

Keith: ‘It was possibly the weirdest thing I have ever experienced’

Finally, after three hours, the doctor tells me they can find nothing wrong. All my test results are fine. My episode is put down to something called transient global amnesia (TGA) and I am free to leave.

I’ve been keeping my family in the loop via text, and now it’s confirmed: I haven’t had a stroke, I haven’t got a brain tumour, all my vital signs are good. We go home.

But what on earth is TGA? And why have I, a journalist for more than 40 years, never even heard of it?

What is TGA?

Transient Global Amnesia is where, for a short period of time, you cannot form new memories (called anterograde amnesia) and have difficulty recalling recent memories (retrograde amnesia), but you appear otherwise mentally alert and lucid.

Transient means ‘passing’, and an episode of TGA rarely lasts more than few hours. My own event, as far as we can tell, lasted no more than 15–20 minutes.

I spoke to neuroscientist and author Dr Dean Burnett, who explained: “The formation of our memories is an on-going production line, and it’s a very demanding, and delicate system. We are not supposed to ever stop making memories.”

During an episode of TGA, sufferers will often ask the same questions repeatedly as they are unable to retain new information. I apparently kept asking for the day and date.

Who is likely to have TGA?

The condition usually occurs in people between the ages of 50 and 70 – I’m 64. It occurs in about five people per 100,000. The paramedics who came for me had seen a similar case recently.

We humans are capable of recognising a danger that isn’t directly in front of us, and that is essentially what causes stress

What causes TGA?

More than 50 years after its initial description, TGA remains one of the most enigmatic syndromes in clinical neurology. Quite simply, no one knows what causes it.

Theories include some form of epileptic event (I have no history); a problem with blood circulation to, from, or around the brain (a brain scan showed nothing untoward); mild head trauma (nope); or some kind of migraine-like phenomenon (never had a migraine in my life).

About a third of TGA attacks are associated with some form of trigger event, including sudden temperature changes, sex, vigorous exercise, and emotionally traumatic or stressful events.

Dr Burnett said: “Everything we do feeds into our brains, so that is why it’s so difficult to identify what causes TGA. There seems to be no reason for it, and it is, by its very nature, a difficult thing to study because it is so fleeting. By the time it is diagnosed it is usually over.”

At A&E, they believed stress could have precipitated my event, as we were dealing with an emotionally draining family crisis. Perhaps my overloaded brain needed a timeout?

“Stress has many knock-on physical and chemical effects on us,” Dr Burnett explained. “In animals, the fight-or-flight response means that if they see a predator, they run or are eaten. But we humans are capable of recognising a danger that isn’t directly in front of us, and that is essentially what causes stress.”

Dr Burnett said he would not be surprised if there was a spike in TGA – along with many other mental health issues – in the coming months, sparked by the pandemic pressure and anxiety. Indeed, a teaching hospital in Germany reported 16 TGA cases in the first four months of lockdown, compared to a previous annual average of 9.7 cases.

What next?

The good news is that TGA rarely has any after-effects. It’s possible to have further episodes, but it is considered unusual to have more than two. Because the cause is unknown, and it’s unlikely to recur, there’s not much you can do to help yourself, either.

“It is very disturbing, and can be terrifying, but thankfully it is temporary,” said Dr Burnett.

All I can say is that my TGA incident was possibly the weirdest thing I have ever experienced. The year 2020, eh? It would probably be best to forget it all, anyway.

Dr Dean Burnett is author of ‘The Idiot Brain’, ‘The Happy Brain’, and for teens ‘Why Your Parents Are Driving You Up the Wall and What to Do About It’. Find out more at deanburnett.com

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