Most of us have had an experience like this: we turn our heads to the side in bed and see a strange shape. It has a weird line to it, and it's an odd color, and it's suspended in a strange way. We're wary. We're confused. Whatever we're experiencing doesn't 'ring a bell,' for us. And then we turn our heads slightly, and recognition dawns. That thing we're seeing was the fringed scarf that we borrowed from someone last night for the walk home through the rain. It's in that weird position because we hung it between the desk and the doorknob to dry.
When we lie back down, most of us keep this sense of recognition. Now that we know what it is, we can see and understand the way the scarf moves in the draft from under the door. Now that we know what we're 'looking' for, we can see it clearly. We can recognize it the way we recognize everything else in our life. But people with a syndrome called agnosia don't have this continued recognition. The second the object goes away, it goes back to being alien.
Photo by Frogstar via Shuterstock
General Visual Agnosia
There are many different types of agnosia. All are caused by trauma, tumors, or strokes, and all represent small slice of personal blindness. Not an absolute blindness to the sight, but a blindness to the memory of the sight, an inability to see things you've seen many times before. A small hit, a small tumor, or a small stroke, and your brain can simply wipe out your ability to recognize anything.
This was the illness of the famous man who mistook his wife for a hat. General agnosics are able to see just fine, but the things they see are a jumble of shapes and colors. The man described seeing a deep red conglomeration of shapes, clustered around a center, with a narrow green line hanging beneath it. Some people reading this might recognize the red and green object as a rose. The man never did. When he got up to go, the man stood up and looked for his hat. His still-seated wife, with her even, round, roughly head-shaped coif, looked enough like his hat for him to grab at her head, trying to pick up his hat to put it on.
Not all visual agnosia is that all-encompasing. An injury can take out the ability to recognize anything, or it can slice away recognition in sections. Dorsal simultanagnosia, for example, can take away your ability to see more than one thing at the same time. Show a person a line drawing of three different objects superimposed, and they will seize on one and be unable to describe the rest. Color agnosics can't recognize that, for example, a green cow is an unusual hue. Topographical agnosia robs people of the ability to let their visual cues guide their direction. A topographical agnosic can tell you that the table is to the left, but can't get there. Category-specific agnosia patients can't distinguish one group of objects from another, even simple distinctions like living things from nonliving things. A table and a cat are equally likely to be alive to them. Any ability to coordinate between seeing the incoming photons and responding to them can be taken away.
The most famous of agnosias is prosopagnosia, or face-blindness. This is also the only type of agnosia that can be 'learned.' Everyone has a section of the brain, the fusiform gyrus, that deals with facial recognition. If that is damaged, recognition is gone. This section, however, needs input and practice at several key stages of development to be of any use. Babies born with cataracts, which often can't be removed until six to eight months in, are face blind. Children who have been blinded and don't get their sight back until adulthood are often face blind. It's thought that some children who are neglected, and unable to see a parent's face responding to their own, can become face blind.
Face blindness is often so subtle that Heather Sellers , who had such an intense case that she wrote a memoir about it entitled You Don't Look Like Anyone I Know, didn't realize she was face-blind until her thirties. Face blindness isn't, according to her book, the blankness that most people assume it is. Most of the time, when someone was in her boss's office, wearing her boss's clothes, talking like her boss and with her boss's physicality, she figured out it was her boss so quickly that she never noticed not recognizing the face. She saw faces, like anyone else, and if she occasionally forgot a face, or mistook one person for another, or walked by someone in the street without recognizing them, well, who didn't?
When she took her boyfriend to meet her mother, she managed to walk by her own mother in a grocery store on the way to the house. When her boyfriend recognized her mother from the grocery store once they got to the house, Sellers thought he was kidding, and then brushed the whole incident off. Later, when she took a face blindness test, which showed a picture of a face with the hair and the ears cropped out, she didn't recognize it as the tester sitting right in front of her. Face blind people sometimes recognize who they're talking to, and sometimes they don't, depending on if the person they're recognizing are in a familiar setting, have the same hair, and whether or not the crowd around them is big. Meet a face blind person for lunch in their office, and they'll recognize you. Ask them to meet in a crowd, and you might as well be asking them to pick out one fish from a whole school streaming past. Sellers stresses that the worst part of the condition isn't the small misunderstandings, although those can be disastrous, but the cumulative effect. One misunderstanding after another racks up until the person is in a constant state of wondering if they know this person, or the next person, or the next.
Topoagnosia and Astereognosia: Tactile Agnosia
There's an old joke that goes like this: A man comes into a doctor's office. He says, "Doctor, I think something is really wrong with me. When I touch my leg it hurts and when I touch my stomach it hurts and when I touch my head it hurts. No matter what I touch, it hurts!" The doctor looks at him, raises an eyebrow, and says, "Your hand is broken." Topognosis is the ability to tell which part of the body is being touched. Topoagnosics have no ability, without looking, to understand what part of their body is being touched at any particular time. A pain can come because their hand is on the stove, or because their shoes are too tight.
Astereognosia negates people's ability to recognize what they're touching. Although they may be able to describe the points of it - going back to a rose, they can recognize a long rigid stick with points on it leading to thin, soft sheets stacked on top of each other - but they can't understand what the object is unless they can see it. The feel of objects doesn't create a memory that can be accessed and compared to whatever they're touching. Every sensation is a new sensation, and a strange one.
And it's that eternal newness and strangeness that characterizes all agnosias. Whether it's figuring out that, to go to the door on the left you have to turn your feet in a certain way, despite having gone to that door on the left plenty of times, or if you need to figure out each day if that person waving to you on the street is your mother with a new haircut or a crazy person fixated on you. Agnosics can see, can hear, can know, can acknowledge, but they cannot fall back into the patterns that most of us can use to navigate our way through the world. Engaging freshly with the world every time you encounter it has an allure. You never look at a flower as 'just another rose,' if it's an object of mystery from the first glance until you finally figure it out, but the drawbacks are self-evident. There's little-to-no cross between the agnosic world and the so-called 'normal' world. Taking a look at the differences as described to us, though, lets us see exactly how much we rely on what we've seen before to understand what we're seeing now. We live our lives by establishing unconscious patterns - now we see what happens when those patterns are ripped away.
Top Image: Che
Hat Image: Jorge Royan
Face Image: G.dallorto