Those who see without looking: the curious phenomenon of hemineglect

A camera, when it is recording, captures images. But behind that camera there is always a production team that pays attention and gives importance to the information that has been captured. It elaborates the information, manipulates it, selects it, understands it. It processes it to then show the result of that processing to a public that will store that information, and use it later.

Our brain works the same. We capture stimuli, we constantly receive information from the outside through our eyes and, just like a production team would do, it is processed by our brain, and stored, to use it at other times of our day a day.

But what if the lens on that camera captured images for a while, but then at full speed? information that it has captured will not be paid attention to it and it will simply stay there, useless, useless? This is what happens to people who have an attention disorder called hemineglect or spatial neglect.

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What is hemineglect?

Hemineglect is a disorder that appears as a consequence of acquired brain damage (for example, a brain tumor, ischemia or hemorrhage) in the parietal lobe Rear right, mainly. Precisely because it is in the right hemisphere and because the pathways that go up to the brain are contralateral (they are cross each other, going from one side to the other), all that the left eye captures is what is not later process.

The key to this disorder is that the left part of what is in the attentional focus is not processed, no attention is paid to it.

People who suffer from this disorder experience some situations in their day to day, such as the following: they only make up the left side of the face (since the left right of the face that is reflected in the mirror is captured by the left eye), at mealtime they only eat the right side of the plate and everything should be placed on this side. When they try to read, they fragment sentences and words, so what they read doesn't make any sense and they have to make it up. They also have trouble writing, as they don't handle spaces well. In addition, this disorder also affects the extremities on the left side, since they cannot see them and forget to use them.

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How is it different from blindness?

The difference between blindness and hemineglect is that a blind person can learn to locate objects in a 360 degree space, with difficulties, of course, but achieving it. This is due, in part, to the fact that the person knows that there is "something" in that space and is aware that, although not see the objects that are there, in the end he manages to achieve a small normality in his life despite the limitations. On the other hand, for a person with hemineglect, her space only has 180 degrees, because the other 180 are not there for her. People with this disorder have anosognosia (lack of awareness of disease).

As a result of this, it can be thought that, on some occasions, the "implementation team" that we have in our brain than the lens that captures images, because in the future we may be able to change that lens for another if it is damaged. But... Could we one day be able to change a damaged cognitive function for another that is functional?

Currently there are various techniques to rehabilitate people who suffer from this pathology. The goal of such rehabilitation is not to cure hemineglect, as hemineglect is a chronic disorder. However, work is being done to teach people who suffer from the disorder to live with it and have a better quality of life. Some of the most effective techniques are the use of prisms, (placing these next to the right eye so the person could see what is to their left by looking the mirror) and cognitive re-education (teaching the patient that he must turn his head to the left enough to be able to perceive his entire visual field with the left eye). right).

Author: Maria Vega Sanz