Patient E.P.

E.P. is an 85-year-old man, a retired laboratory technician. He is 1.80 meters tall, combs his gray hair impeccably, and his ears are very big. He is affable, friendly and gentle. Laughs a lot. At first glance, he looks like any jovial grandfather.

On any given morning, E.P. wakes up, eats breakfast and goes back to bed to listen to the radio. However, when he is back in bed, it is not always clear whether he just had breakfast or woke up. He frequently eats breakfast again and goes back to bed to listen to more radio shows. Some mornings, he takes the breakfast for a third time. He watches television, which can be very exciting from one moment to the next, although shows with a clear beginning, middle, and end may pose him a problem. He prefers History Channel, or any topic about World War II. He goes for walks around the neighborhood, usually several times before lunch, sometimes for up to three quarters of an hour. He sits in the garden. He reads the newspaper; it must be like getting out of a time machine. Bush who? Iraq what? Computers when? When finishing a header, E.P. has usually forgotten how it starts.

On a warm spring day, I met E.P. at his house, a light-filled bungalow in a San Diego suburb. I traveled by car with Larry Squire, a neurologist and memory researcher, and with Jen Frascino, a research coordinator in Squire's lab, who regularly visits E.P. to apply him knowledge tests. Although Frascino has been at E.P.'s about two hundred times, he always greets her as if she were a stranger.

Frascino sits across from E.P. at his dining room table and asks him a series of questions that test his common sense: what continent is Brazil on, the number of weeks in a year, at what temperature does water boil. She wants to prove what IQ tests have already confirmed: he's no fool. He patiently answers all the questions, all correctly, I imagine that with the same feeling of bewilderment that I would have if a perfect stranger came to my house, sat down at my table and, very seriously, questioned me about the boiling temperature of water.

"What should you do if you find a sealed envelope on the street, with an addressee and a stamp?" Frascino asks.

"Well, one puts it in the mailbox. What else?" He laughs and looks at me knowingly, as if to say "do these people think I'm an idiot?" However, he feels that the situation calls for courtesy and he looks back at Frascino to add:

"But that's a really interesting question. Very interesting." He has no idea that he has heard it many times before.

E.P. has a metallic medic alert bracelet on his left wrist. Although its function is obvious, I ask anyway. He turns his wrist and, very calmly, reads:

"Hmm. It says memory loss."

E.P. doesn't even remember that he has a memory problem. That is something he rediscovers every moment, and since he forgets that he always forgets, every lost idea seems like a random mistake, a nuisance, and nothing more.

15 years ago, the herpes simplex virus invaded E.P's brain. The infection produced extensive lesions in his brain: by the time the virus decreased, two chunks of brain mass had disappeared from his temporal lobes, each the size of a walnut. With them, almost all the memory of E.P. left.

The virus attacked with unusual precision. The medial temporal lobes, one on each side of the brain, include a curved structure called the hippocampus and a number of adjacent regions that together convert perceptions into long-term memories. Memories are not stored in the hippocampus, but rather reside in the neocortex; but the hippocampal area is the part of the brain that causes them to be retained. E.P.'s hippocampus was destroyed, and without it, E.P. is like a video camera whose head doesn't work. It sees, but does not record.

E.P. suffers from two types of amnesia: anterograde, which prevents him from forming new memories, and retrograde, which prevents him from recalling previous memories (at least not since 1960). His childhood, his service in the merchant navy, World War II, all of that is very vivid. But as far as he knows, gas costs 30 cents a gallon and man never made it to the Moon.

For E.P., space only exists to the extent that he can see it. His social universe only encompasses the people in the room. He lives under a narrow spotlight surrounded by darkness.

Without memories, E.P. has been totally out of time. He has no stream of consciousness, just droplets that immediately evaporate. If they took away his wristwatch or, more cruelly, changed the time, he would be completely lost. Trapped in the limbo of an eternal present, between a past he can't remember and a future he can't contemplate, he leads a sedentary life, free from worries.

"He is happy all the time. Very happy. I guess it's because there's no stress in his life." says his daughter, Carol, who lives near her father.

"How old are you now?" Squire asks.

"Let's see, 59 or 60. You got me. My memory isn't that perfect. It's pretty good, but sometimes people ask me questions that I just don't get. I'm sure it happens to you sometimes."

"Of course" says Squire, kindly, although E.P. has erred by a quarter of a century.

Although there is no consensus regarding the number of existing memory systems, memories are usually divided into two types: declarative and non-declarative. Declarative memories are things we know we remember, like the color of the car or what happened yesterday afternoon. E.P. has lost the ability to form new declarative memories. Nondeclarative memories are things we know without consciously thinking about them, such as riding a bicycle. These unconscious memories do not depend on the hippocampus for their consolidation and storage: they take place in completely different areas of the brain. As patients like E.P., Henry Molaisson, or Phineas Gage have surprisingly shown, you can suffer damage to one region of the brain and the rest will continue to function well.

I want to see how E.P.'s non-declarative memory works, so I ask him if he is interested in me joining him on one of his neighborhood walks. "Not really," he replies. I wait and ask him a couple of minutes later. This time he agrees. We walk out the front door as the afternoon sun is in full swing and turn right. I ask E.P. why we don't better turn left.

"I would prefer not to go that way. This is the path I follow. I don't know why," he says.

If I asked him to map the route he takes at least three times a day, he would be unable to do it. He doesn't even know his own address. However, after so many years of doing the same walk, the journey has been burned into his subconscious. His wife, Beverly, now lets him go out on his own, though one wrong turn and he would be completely lost.

Sometimes, he returns from his walks with multiple objects that he has picked up along the way: a pile of round stones, a puppy, someone's wallet. He can never explain how they came into his possession.

"Our neighbors love him because he approaches them and starts chatting with them", Beverly tells. Although he thinks he is meeting them for the first time, he has learned by habit that these are people he should feel comfortable with, and he interprets these unconscious feelings of comfort as a good reason to stop and say hello.

We cross the street and I find myself alone with E.P. for the first time. He doesn't know who I am or what I'm doing with him, although he seems to sense that I'm there for a good reason. He is trapped in the ultimate existential nightmare, blind to the reality in which he lives. I have the urge to help him escape, at least for a second. I want to take his arm and shake him. I want to tell him: "You have a rare and debilitating memory disorder. You have been missing the last 50 years." In less than a minute, he'll forget this conversation ever took place. I imagine the sheer horror he would feel, the momentary clarity, the gaping void that would open before him, then close just as quickly. And then the passing of a car or the song of a bird would immediately return him to his bubble where everything that surrounds him is alien to him.

We turn and walk back down the street whose name he has forgotten, past waving neighbors he doesn't recognize, heading for a home he doesn't know. In front of the house there is a car parked, it has tinted windows. We turn to look at our reflection. I ask E.P. what he sees.

"An old man" he answers. That's all. ▯