Transient Global Amnesia: Not as Scary as it Sounds

When my friend Marielle* returned from a whirlwind trip to New York City, her stories about the fabulous Broadway shows she had seen with her daughter paled beside the personal drama that capped her visit: a mysterious bout of transient global amnesia (TGA).

Because it sounds so much like transient ischemic attack, more popularly known as a TIA or mini-stroke, transient global amnesia is a scary sounding diagnosis that may cause some people to think they are in declining health or have a serious medical problem. But this temporary loss of recent and current memory in which one's brain becomes like Teflon and memories just don't stick is usually an anomaly that does not reflect a more serious health problem.

Transient global amnesia occurs when blood flow is interrupted to the brain's short-term memory region, the hippocampus. In a CNN website article, Harvard Medical School Professor of Neurology, Dr. Louis Caplan, compares the hippocampus to a tape recorder. "The hippocampus is responsible for initially recording the information so you can play it back," he said. "So if it's not working, you won't get the information."

Although she is in her 60s, my friend Marielle is still as trim and fit as many women in their 30s; she posed as a svelte Miss February for her service club's fund-raising calendar (tastefully dressed, of course), takes brisk daily walks and eats mainly free-range meats and organic fruits and vegetables, much of which she grows herself. Marielle was devastated to be blind-sided with sudden memory loss thousands of miles from home and diagnosed with such a serious sounding ailment as transient global amnesia. Maybe she wasn't as healthy as she thought she was?

It turns out that even very healthy people like Marielle can be stricken with transient global amnesia, and chances are good it will be a one-time occurrence. Even better, a single episode of transient global amnesia does not mean one is more likely to have a stroke in the future or experience other neurological problems, according to the Mayo Clinic website.

What was so perplexing and frightening for Marielle's 32-year-old daughter, with whom Marielle was walking through Central Park at the time her transient global amnesia occurred, was that her usually lucid and articulate mother had no idea where she was nor how she had gotten there. She knew her name was Marielle and that Cynthia was her daughter. Being the ace gardener she was, she could even identify many of trees and flowers in her path, and she could name members of her family and even the city where she was born.

Because it was so unlike the usually observant Marielle to be so confused about her present circumstances, Cynthia wisely hailed a taxi and took her mother to the nearest hospital, where Marielle underwent several diagnostic tests, including an EEG and MRI. Within hours her memory started to return. Marielle could still recall a doctor coming into her room five minutes after he'd left and could even describe what he looked like, the first recent memory that had stuck since the start of her transient global amnesia episode in Central Park. Like a magical paint with water picture book for children, new memories gradually started to fill up Marielle's "page," although she could remember nothing about that morning's walk in Central Park, her trip to the hospital or the diagnostic tests she had undergone - nor have those memories ever returned.

When Marielle shared her strange tale with me recently, she asked if I had ever heard of transient global amnesia since she knew I was up on many health topics. I had to admit that transient global amnesia was a new term for me, and because Marielle seemed anxious about her future - What if she'd been by herself? Could it happen again? Was this the beginning of a downhill slide into dementia? - I decided to do some research about this curious medical phenomenon.

As Marielle has since learned from her doctors, once other neurological causes such as epilepsy are ruled out, there is little cause for concern after a fluke episode of transient global amnesia. Marielle will undergo some further testing to rule out more serious problems, but with her enviable fitness profile, chances are she will receive a clean bill of health.

No one knows exactly what caused Marielle's transient global amnesia. According to an article about transient global amnesia on the Mayo Clinic website, common triggers are "sudden immersion in cold or hot water; strenuous physical activity; sexual intercourse; medical procedures, such as angiography or endoscopy; and acute emotional distress, as might be provoked by bad news, conflict or overwork."

Some health researchers have also suggested a link between transient global amnesia and migraines and, perhaps, even a link between transient global amnesia and the use of statin drugs to lower cholesterol. Marielle took no prescription medications and was not a migraine sufferer.

The most likely cause of Marielle's transient global amnesia was either strenuous physical activity from all the running around she and Cynthia had done -- cramming in as much art, theater and people watching as they could in the short space of a week -- or it could have been sparked by the emotional distress of being in a strange place, even one as enchanting as Manhattan.

It is unlikely that most people will ever experience transient global amnesia or know someone who does. According to WebMDs eMedicine website, the incidence of transient global amnesia is only 5.2 cases per 100,000 population per year in the United States. Odds are bit higher for those older than 50, the most common age group to experience transient global amnesia, about 23.5 cases per 100,000 population per year.

The Mayo Clinic website warns that people who have experienced an episode of transient global amnesia often worry about a recurrence, as unlikely as that possibility may be. "A symptom as dramatic as memory loss often heralds a serious underlying disease," the prestigious medical website explains. "Transient global amnesia is an exception, but it can be hard to let go of the fear that you have a tumor or had a stroke."

Most likely, as time goes by, Marielle's experience with transient global amnesia will become just another funny story that gets embellished over time as most stories do. Even with some fanciful "facts" mixed in, sharing the story with others could prove helpful to others who may find themselves in the presence of a friend or loved one who experiences similar disorientation and memory loss. While such serious symptoms still merit immediate medical attention, they will hopefully find comfort in knowing it may just be transient global amnesia, a scary sounding health condition that, in most cases, is temporary and will never recur.

*Author's Note: The names of the people in this story were changed to protect their medical and personal privacy.

Sources:
friend's experience
http://www.cnn.com/2009/HEALTH/11/04/transient.global.amnesia/index.html
http://emedicine.medscape.com/article/1160964-overview
http://www.mayoclinic.com/health/transient-global-amnesia/DS01022