“IN A STUDY OF WHAT TRIGGERED TGA, SEX WAS THE MOST COMMON PRECIPITANT.”
have a lot more to learn about the way memory works. “The growing evidence that emotional and psychological factors can play a role in triggering TGA demonstrates the intimate link between emotion and memory,” she says.
The biggest difference between TGA and a more common type of amnesia is its transient nature.
“The most common type of amnesia is anterograde amnesia which occurs after a traumatic brain injury or a stroke. Patients have difficulty learning new information,” Baird explains.
People experiencing anterograde amnesia have difficulty with day-today things and learning new things. “If you were to try and teach something to a person in the middle of a TGA episode, a list of words for example, they would struggle. But once the episode has resolved, they’ll have no problems with that. But a person with anterograde amnesia will have ongoing problems remembering new information.”
TGA first appears in medical literature in 1956, but there are still a lot of unanswered questions about the condition. Research into TGA has uncovered a number of triggers including strenuous physical activity, emotionally arousing or stressful events or a sudden change in body temperature (think diving into an ice-cold lake).
Baird, who has written extensively about sex and the brain in her 2019 book, Sex on the Brain: How Your Brain Controls Your Sex Life, also notes that sex is another common trigger.
“In a study that specifically explored what triggered Transient Global Amnesia, sex was the most common precipitant, reported in a third of the 21 cases,” she says. “Sex ticks two of the boxes of the known triggers for this type of amnesia: it can be both physically strenuous and emotionally arousing. Particularly if the sex is with someone who is not your usual partner.”
The trigger for Paul Rupil’s TGA episode isn’t totally clear but there are a number of possibilities. “We’d had some bad news from Natalie’s auntie who lost a property in Kangaroo Valley [in the summer bushfires], so that had shaken us all up a bit,” Paul recalls. So it could have been stress. Another factor could be the surgery that Paul had
While TGA is a temporary or ‘transient’ episode, neurological amnesia has a lasting impact.
In 2005, Lisa Cox, then 24, had a stroke, brought on by a Streptococcus-A infection. In the aftermath she needed multiple amputations and has been left with permanent disability and amnesia.
Fifteen years on, Lisa still has amnesia. “I don’t remember several months before and after the stroke. Even a trip to Europe, years before, is a fairly lost memory,” she tells MiNDFOOD.
Discovering that she had lost part of her memory was a difficult experience. “There were several times when my family would talk to me about ‘big events’ (like resigning from a job and starting another, travelling and relationships, buying a car) but I had no recollection.
“Other lost memories were more distressing.
“I forgot that certain people had passed away so had to relive that grief.”
While living with amnesia is frustrating at times, Lisa says it’s a blessing she can’t remember the early days of her recovery. “I’m grateful I still have memories from my childhood,” she adds.
Although big gaps in her memory remain, Lisa can still remember the German she learnt in school, phone numbers of friends from her teen years and the lyrics to certain ’90s songs. “Sometimes I have to laugh,” she says. had on his bicep. “I was taking anti-inflammatories and I’ve been advised to stop taking those.”
Dehydration could also have played a part. Paul has another theory – his TGA episode wasn’t caused by just one trigger, it was an accumulation effect. A ‘perfect storm’ scenario. “Maybe all the factors working together was the cause,” he says.
Paul is also someone who experiences migraines.
According to the Mayo Clinic, if you have migraines, your risk of TGA is significantly higher than that of someone who has never had migraines. In fact, one 2018 study, published in Neuropsychiatry journal, found that those with a diagnosis of migraine had six time greater odds of having TGA.
“Migraine is considered a vascular condition,” explains Baird. “The current theory about TGA is that it’s vascular; it’s related to blood flow. It seems to be the mechanism behind migraine and TGA.”
Paul and Natalie didn’t know about it at the time, but 12 months prior to Paul’s episode, his father, Lucio, 70, had also experienced TGA.
“When I rang Paul’s mum she knew all about TGA. She wasn’t concerned at all because she knew it was temporary. She knew he wasn’t in any danger,” Natalie tells MiNDFOOD.
There is not a great deal of research into TGA and genetics, and so it’s not known if genetics play a part. For Natalie, speaking to Paul’s mum was reassuring. “I thought, ‘Well [Paul’s parents] have been through this and they didn’t feel worried enough to tell us,’ so I started to relax a little bit,” she says.
During the episode Paul experienced confusion, but the amnesia itself protected him from the full story. He was confused, but didn’t remember enough from one moment to the next to fully comprehend what was happening to him.
Natalie, on the other hand, was very scared. Baird says this is typical in a TGA episode. “It’s very frightening, particularly for the people witnessing the episode,” she says.
But, while TGA is a difficult experience, Baird says that it’s nothing to be worried about. “It’s very rare, but when it does happen it lasts less than 24 hours. It’s considered a benign condition. The couple of patients that I’ve seen in my clinical practice do fine on formal memory tests – there are no lasting problems with memory.”
When his memories began to come back, Paul was discharged from hospital and allowed to go home. But although he’d been reassured that everything was okay, he felt wary.
“I was really guarded and cautious about doing things [like driving the car or going to the local shops]. It’s hard to know whether there was really any danger. It was just the uncertainty.
“The overriding feeling has been, ‘Wow, can that stuff really happen? Am I really okay? Am I really back to normal?” he says.
Six weeks on from the episode, Paul is well. His doctors tell him that he has made a complete recovery and that there will be no long-term complications. But Paul is still looking for answers.
He has all but six hours of his memory back (the nature of TGA means that his brain didn’t record anything that happened during the episode, so he’ll never remember his time in the hospital) and yet he remains unsettled by the experience.
“People have been shocked and intrigued when they find out about my [TGA] episode. No-one that I’ve told has ever heard of it before,” he says.
“People have been amazed that it’s possible to lose your memory, and then get it back again.” mindfood.com/training-boost-memory