Posts Tagged ‘cortical blindness’

The Effects of Brain Damage

July 21, 2019

This post is based on a book by Stefan Van Der Stigchel titled “How Attention Works: Finding Your Way in a World Full of Distraction.” Visual neglect is a condition in which patients experience problems moving attention to the left or the right side of the visual world. Neglect usually results from damage to the right hemisphere of the brain. The attention regions in that part of the brain are responsible for moving attention to the left visual field. This condition has different levels of severity, and patients with the most severe form are completely unaware of what goes on in the neglected half of their world. When someone with this condition eats they eat only the food on the right-hand side of the plate. When they finish eating they believe that they have eaten everything because they have no access to the information on the other side of the plate. Only when his plate is turned around does the other half of his meal appear in the “intact” part of his visa world and does he realize that he hasn’’t finished his food after all. Neglect patients are actually able to move their attention, but only after receiving clear instructions and only for a short period of time.

Dr. Van Der Stigchel writes, “Around 25% of all patients with brain damage suffer from some form of neglect. Fortunately, it is usually a short-term problem. This is because there are all kinds of processes in the brain that are disrupted in the acute phase, but that are eventually able to return to normal. After a stroke, for example, excess blood has to be drained off from the brain. When that is done, many brain brain functions return to normal and the problem of neglect just vanishes. Even within only a few days of suffering brain damage, a patient may show no more signs of neglect. However, for some patients neglect remains a chronic condition, meaning that the problems they have with moving their attention are permanent.”

Cortical blindness is different from visual neglect and much more serious. Unlike neglect, cortical blindness is not an attentional deficit. There is no visual information in the blind field to which patients can move their attention. People suffering from cortical blindness cannot see any colors, shapes, or other visual building blocks in the affected field.