Visual Processing Disorder

A visual processing, or perceptual, disorder refers to a hindered ability to make sense of information taken in through the eyes. This is different from problems involving sight or sharpness of vision. Difficulties with visual processing affect how visual information is interpreted, or processed by the brain.Common areas of difficulty and some educational implications: Spatial relation

This refers to the position of objects in space. It also refers to the ability to accurately perceive objects in space with reference to other objects.

Reading and math are two subjects where accurate perception and understanding of spatial relationships are very important. Both of these subjects rely heavily on the use of symbols (letters, numbers, punctuation, math signs). Examples of how difficulty may interfere with learning are in being able to perceive words and numbers as separate units, directionality problems in reading and math, confusion of similarly shaped letters, such as b/d/p/q. The importance of being able to perceive objects in relation to other objects is often seen in math problems. To be successful, the person must be able to associate that certain digits go together to make a single number (ie, 14), that others are single digit numbers, that the operational signs (+,,x,=) are distinct from the numbers, but demonstrate a relationship between them. The only cues to such math problems are the spacing and order between the symbols. These activities presuppose an ability and understanding of spatial relationships.Visual discrimination

This is the ability to differentiate objects based on their individual characteristics. Visual discrimination is vital in the recognition of common objects and symbols. Attributes which children use to identify different objects include: color, form, shape, pattern, size, and position. Visual discrimination also refers to the ability to recognize an object as distinct from its surrounding environment.

In terms of reading and mathematics, visual discrimination difficulties can interfere with the ability to accurately identify symbols, gain information from pictures, charts, or graphs, or be able to use visually presented material in a productive way. One example is being able to distinguish between an /nl and an Imp, where the only distinguishing feature is the number of humps in the letter. The ability to recognize distinct shapes from their background, such as objects in a picture, or letters on a chalkboard, is largely a function of visual discrimination.Visual closure

Visual closure is often considered to be a function of visual discrimination. This is the ability to identify or recognize a symbol or object when the entire object is not visible.

Difficulties in visual closure can be seen in such school activities as when the young child is asked to identify, or complete a drawing of, a human face. This difficulty can be so extreme that even a single missing facial feature (a nose, eye, mouth) could render the face unrecognizable by the child.Object recognition (Visual Agnosia)

Many children are unable to visually recognize objects which are familiar to them, or even objects which they can recognize through their other senses, such as touch or smell. One school of thought about this difficulty is that it is based upon an inability to integrate or synthesize visual stimuli into a recognizable whole. Another school of thought attributes this difficulty to a visual memory problem, whereby the person can not retrieve the mental representation of the object being viewed or make the connection between the mental representation and the object itself.

Educationally, this can interfere with the child's ability to consistently recognize letters, numbers, symbols, words, or pictures. This can obviously frustrate the learning process as what is learned on one day may not be there, or not be available to the child, the next. In cases of partial agnosia, what is learned on day one, "forgotten" on day two, may be remembered Whole/part relationships

Some children have a difficulty perceiving or integrating the relationship between an object or symbol in its entirety and the component parts which make it up. Some children may only perceive the pieces, while others are only able to see the whole. The common analogy is not being able to see the forest for the trees and conversely, being able to recognize a forest but not the individual trees which make it up.

In school, children are required to continuously transition from the whole to the parts and back again. A "whole perceiver", for example, might be very adept at recognizing complicated words, but would have difficulty naming the letters within it. On the other hand, "part perceivers" might be able to name the letters, or some of the letters within a word, but have great difficulty integrating them to make up a whole, intact word. In creating artwork or looking at pictures, the "part perceivers" often pay great attention to details, but lack the ability to see the relationship between the details. "Whole perceivers", on the other hand, might only be able to describe a piece of artwork in very general terms, or lack the ability to assimilate the pieces to make any sense of it at all. As with all abilities and disabilities, there is a wide range in the functioning of different children.