“During an episode of transient global amnesia, your recall of recent events simply vanishes, so you can’t remember where you are or how you got there. In addition, you may not remember anything about what’s presently happening. Consequently, you may keep repeating the same questions because you don’t remember the answers you’ve just been given. You may also draw a blank when asked to remember things that happened a day, a month or even a year ago. You do remember who you are, and recognize the people you know well.
“Transient global amnesia is seemingly harmless and unlikely to happen again. Episodes are short-lived, and afterward, your memory is fine.”
Phyllis Miller was standing in her kitchen, staring at a half-empty glass of water, wondering what she was doing.
The last thing she remembered was leaving the Sports Barn downtown and driving past the University of Tennessee at Chattanooga campus. She had absolutely no recollection of what had happened between then and standing in her kitchen.
"I had left the Sports Barn early that morning after a vigorous workout and not drinking any water," says Miller, 68, an obstetrician/gynecologist and former president of the Chattanooga-Hamilton County Medical Society. "When I got home to get ready to go into the office, I realized something was wrong. I could not recall recent events."
The incident was about three years ago and, despite being a physician, she had no clue about what was going on. She feared she had suffered a stroke. She was wrong.
Turns out Miller had transient global amnesia, a sudden, temporary episode of memory loss that can't be attributed to a more common neurological condition such as epilepsy or stroke. And it's rare. About five out of 100,000 will experience it.
"The symptoms of transient global amnesia usually last for two to eight hours but, in general, resolve within 24 hours," says Dr. Tareck Kadrie, a Chattanooga neurologist. "There may be very subtle effects on memory that can persist for more than 24 hours, but I might begin to question the diagnosis if there are noticeable significant deficits lasting more than 24 hours."
Yet in the vast majority of cases it does not recur, he says. "There are variable estimates of recurrence rate, but it is generally thought to be less than 20 present over a lifetime."
"I was aware of transient global amnesia but hadn't thought much about it," Miller says. "Since then, I have run into several people who have had it — a couple of them being fellow physicians."
While rare, it happens enough that most neurologists will come in contact with it at some point in their practice, Kadrie says.
"This is something we commonly see in neurology," he says. "We do recommend seeking immediate medical attention. The most immediate condition to exclude is stroke."
At the hospital, doctors may order CT, MRI and other brain scans, take EEGs and EKGs, do bloodwork and perform neurological tests.
"Typically, as the syndrome resolves, the amnesia improves, but the patient is often left with a distinct lapse of recollection for a portion of events during the attack," Kadrie says.
He doesn't know of any connection between transient global amnesia and Alzheimer's or any other cognitive disorders. "One is not at higher risk of developing a memory disorder later in life," he says.
Transient global amnesia was first officially diagnosed in 1956 and is characterized by the inability to form new memories over the course of a few hours and also the loss of recent memories. Sometimes these memories come back; sometimes they don't. Except for the loss of memories, TGA usually has no lasting effects on memory or brain function, doctors say.
It usually affects people between 40 and 80 and happens equally in men and women. It can be traced back to problems with blood supply in the brain such as atherosclerosis or aneurysms, as well as through migraine and epilepsy, Kadrie says.
"If these disorders are present, then episodes may be more likely to recur," he says.
According to the National Institutes of Health, amnesia attacks also can traced back to what is medically known as a Valsalva maneuver, the most common of which is pinching the nose and trying to blow air through it; sleep apnea is also another type of Valsalva maneuver. But the amnesia can also occur after such physical activity as swimming, immersion in cold water, intercourse, coughing and heavy lifting.
Early on the morning of her attack, Miller felt like she might be getting a cold, so she put a tablet of cold medicine in a glass of water and planned to drink it when she got back from working out. However, when she got home, she had no recollection of why the glass of water was sitting on the counter.
"I knew something was wrong and called my daughter," she says. "She took me to the emergency room. I thought it might be a stroke, but realized I had no other symptoms.
"I was not particularly scared, but it was sobering thinking something very serious could be going on," she says. "I had a quick discussion with my daughter in between tests to be sure she knew where important papers were."
Miller says that, by the time she got to the emergency room, her symptoms had subsided. Still, she has no recollection of what happened during those missing hours.
"The acute episode (of transient global amnesia) is followed by a period of repetitive questioning, chattiness, etc., which is where I was by the time I got to emergency room, which was rather embarrassing in retrospect," she says.
The diagnosis can be tricky, Miller says, noting that her original diagnosis was a migraine. But even if you think — or someone else thinks — that a person may be experiencing transient global amnesia, a trip to the emergency room is in order just to rule out stroke or other possibilities, Miller says.
"If it is transient global amnesia, no treatment is necessary, " she says.
Contact Karen Nazor Hill at khill@timesfree press.com or 423-757-6396.