Those who see without looking: the curious phenomenon of heminegligence

A camera, during recording, captures images. But behind this camera, there is always a production team that pays attention and values ​​the information captured. It processes information, manipulates it, selects it, understands it. The process will then show the result of this processing to an audience who will store this information and use it later.

Our brains work the same way. We pick up stimuli, we are constantly receiving information from the outside through our eyes, and just like a production team would, it is processed by our brains and stored for use at other times in our daily lives.

But what if the lens of this camera captured images for a while, but all the information captured did not pay attention to it and just stayed here, useless, useless? This is what happens to people with an attention disorder called heminegligence. or spatial neglect.

    What is heminegligence?

    Heminegligence is a disorder that appears as a result of acquired brain damage (For example, brain tumor, ischemia, or hemorrhage) in the right posterior parietal lobe, mainly. Precisely to being in the right hemisphere and since the pathways that go up to the brain are contralateral (they cross, going from side to side), whatever attracts the left eye is what then does not. is not processed.

    The key to this disorder is that the left side of what is in attentional focus is not being processed, He does not pay attention.

    People suffering from this disorder experience certain situations in their daily life such as the following: only the left side of the face is made up (since the right side of the face reflected in the mirror is captured by the left eye). lunch time, they eat only the right side of the plate and everything to put on that side. When they try to read, they fragment sentences and words, so what they read has no meaning and must make it up. They also have a hard time writing because they don’t handle spaces well. Moreover, this disorder also affects the extremities on the left side as they cannot see them and forget to use them.

      How is this different from blindness?

      The difference between blindness and heminegligence is that blind person can learn to place objects in 360 degree space, With difficulty, of course, but with success. This is due, in part, to the fact that the person knows that there is “something” in this space and is aware that even if he does not see the objects in it, he finally manages to reach a small normality in his life despite the limitations. On the other hand, for a person with heminegligence, his space is only 180 degrees, because the other 180 for him are not there. People with this disorder suffer from anosognosia (lack of awareness of the disease).

      Suddenly, we can think that sometimes this “production equipment” that we have in our brain is more important than the objective which captures the images, because in the future we may be able to change this objective for another one. it is damaged. But … Can we ever change a damaged cognitive function for another functional one?

      There are currently several techniques to rehabilitate people suffering from this condition. The goal of this rehabilitation is not to cure heminegligence, because it is a chronic disorder. However, work is underway to teach people with the disease to live together and have a better quality of life. Some of the most effective techniques are the use of prisms (placing them to the side of the right eye so that the person can see what is to their left when looking in the mirror) and cognitive rehabilitation (learn from patient to turn his head to the left enough to be able to perceive his entire visual field with his right eye).

      Author: Maria Vega Sanz

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