Unforgettable patients

This past month, I saw two cases of transient global amnesia. It's a remarkable malady -- the patient is unable to lay down new memories for a brief period. Old memories are untouched, personality is unchanged, and there are usually no other associated symptoms. After a few hours, they get better. Most face no futher complications, and in most cases no satisfying etiology is uncovered.

Since we saw both cases within a few days, and since my neurology attending has only seen five or six in her career, I found it reasonable to assume we were at the beginning of an epidemic. I imagined some virus would soon render us all amnestic for a day, but then we'd spontaneously get better, and no one would be the wiser.

My first patient was an athletic 68 year old woman who had already recovered by the time I saw her. The medical team was just looking for an explanation for her reported confusion the day prior. She remembered waking up, fixing up a bagel and coffee, and nothing else for about ten hours. What's amazing is she had plans to meet friends for brunch, and followed through on those plans. She got in her car, drove half an hour (following printed directions) to a place she'd never been, and joined her friends for a meal. One of the friends remarked that she was acting odd, confusedly repeating remarks and questions. But apparently she was not so odd that they stopped eating, or cancelled a leisurely bike ride across the countryside. It was only at the end of the day's activities that someone was concerned enough to take her to the hospital. But after a few hours in the ER, her ability to lay down new memories returned. She felt fine, except for the disappointment of "missing" the brunch and bike ride.

My other patient was a similarly active 70 year old woman. Her amnesia was in progress, and it was terrifying. Her working memory was no longer than ten or fifteen seconds -- you could literally ask the same question, over and over, with her showing no hint of recognition that she kept supplying the same answer.

Her family was a wreck. The husband was stricken with guilt that he took his wife gardening in the hot sun, figuring she'd had some kind of heat stroke. The daughter was afraid she'd lost her closest confidante forever. It was a tremendous relief to them when I said, with some confidence, "This is something we've seen before -- I expect she'll get better in a matter of hours."

What's amazing about these cases is how well the patients can function with little or no short term memory. My first patient was able to follow pre-printed directions to a new place, and when there, managed to "go with the flow" well enough to avoid causing too much concern. My second patient was notable in that she was surrounded by family, all day, yet no one was really sure when her symptoms started. Her husband sheepishly admitted that he might never have learned anything was wrong -- it was only with the daughter's complex, detail-oriented conversation that the patient's deficit became apparent.

After these cases, I dug up some TGA research, and consulted Adam Sandler's romatic comedy 50 First Dates. The closest my patients come to anything in the movie is "10-second Tom" -- but he was provocative about his impairment, whereas my patients were docile and agreeable. Nor were they confabulatory like this patient with viral encephalitis, whose short term memory lasted several minutes.

In cases like this, personality and outlook are not affected. But maybe that's obvious -- if nothing registers, there's nothing to get angry or sad about, and people are free to be themselves.

One wonders if the incidence of transient global amnesia is much higher -- but the nature of the disease, and subsequent lack of initiative, prevents solitary people from noticing or doing anything about it. Then, the patients get better -- and wonder where the day went.

Cross-posted to LingualNerve.com