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A visual processing disorder refers to difficulties processing motion, space, pattern, light or form. Although a visual processing disorder can be caused by damage or abnormal development in the eye or optic nerve, it is often the result of damage or abnormal development in the visual networks in the brain.

Visual Processing of Spatial Relations

The ability to perceive the location of objects in relationship to other objects is a critical skill in reading, math, and handwriting, where a child must be able to determine the correct placement of lines and angles or curves within a shape as well as the distance between shapes. Individuals who have difficulty with this type of visual processing seem unusually clumsy or accident prone, often have difficulty reading or may read slowly, and can have poor handwriting (dysgraphia).

Visual Discrimination

Visual discrimination allows us to tell the difference between similar objects and recognize objects and symbols when only part of it is seen. Individuals who have visual discrimination disorders often mix up letters or numbers and have difficulty reading or scanning pictures for information.

Visual Perception

Different networks in the brain are used to recognize letters, numbers, symbols, words, faces, locations, buildings or pictures. Abnormal development or damage to one of these areas can disrupt the ability to process one or more specific types of visual forms.

In cases of prosopagnosia, for example, (Dr. MacAlpine has this particular form of visual procssing disorder), the individual cannot recognize familiar people and may fail to recognize themselves in a picture or mirror. In cases of geographic agnosia, which often appears together with prosopagnosia, the individual has difficulty recognizing places and buildings.

Individuals with apperceptive agnosia have great difficulty forming visual memories of objects and are unable to match, copy or draw objects from memory. In associative agnosia, which often appears together with apperceptive agnosia, individuals have difficulty recognizing or desribing the use or purpose of objects. Simultagnosia refers to an inability to see the whole as a sum of parts; although individuals with this problem can see parts of a visual scene, they can't process the whole scene simultaneously. In partial visual agnosia (visual access problems), what is learned on day one, "forgotten" on day two, may be remembered again later. Simultagnosia is sometimes referred to as a visual integration disorder.

Visual Pursuit and Tracking

The ability to track moving objects while seated or standing, and the ability to keep the world stable when the head or eyes are moving or scanning the environment is an ocular-vestibular disorder. Individuals who have visual pursuit disorders have difficulty watching moving objects (e.g. on videos or computer programs), difficulty copying from the board, difficulty reading, and can be clumsy or have difficulty moving through space.

Alice in Wonderland Syndrome

Alice in Wonderland Syndrome is a visual processing disorder in which the individual experiences distortions in time and space so that objects appear smaller, as if down a tunnel, or time appears to stand still. This disorder is typically the result of a viral infection or migraine headaches that affect the visual pathways in the brain.  While it is disturbing to experience, the symptoms resolve on their own within a short period of time, although here may be several episodes over a series of weeks.   For more information see: Perez Mendez, C., Martin Mardomingo M, Otero Martinez B., Lagunilla Herrero L., Fernandez Zurita C. "Alice in Wonderland syndrome due to Epstein-Barr virus infection]"[Article in Spanish],An Esp Pediatr. 2001 Jun;54(6):601-2.

DIAGNOSTIC TESTING

Intervention methods are determined based on the results of individual testing and can include:

• perceptual exercises to improve figure/ground and visual attention

• learning compensatory strategies for recognizing faces, objects, or places

• visual scanning exercises and games

• progressively complex spatial games and activities

• learning how to identify objects from partial information

• visual pursuit exercises

• visual attention training

• bilateral hand-eye coordination games and exercises

COST $140 per hour

Home exercises are provided and are an important part of the rehabilitation process. Visual processing disorders, like other processing disorders, take a great deal of time and effort to improve. Patients and parents/caregivers must be willing to do the home activities and be willing come to therapy for several years if they expect to obtain positive results.