National Centre for Learning Disabilities
Thanks to Larry B. Silver, here is an outline of terms and concepts in perspective.
Information arrives at the brain as impulses, transmitted along neurons, primarily from our eyes – called visual input – and from our ears – called auditory input. This input process takes place in the brain. This central input process of seeing, or hearing, or perceiving one’s environment is referred to as “perception.”
Visual Perception Disabilities:
Children may have difficulty in organising the position and shape of what he or she sees. Input may be perceived with letters reversed or rotated – an e may look like a 9; and E might look like a W or a 3, or an M. This confusion of input shows up almost immediately when the child begins to read, write or to copy letters or designs.
Judging distance is another visual perceptual task which can go awry. A child may misjudge depth, bump into thinks, fall off chairs or knock their food and drink.
Auditory Perceptual Disabilities:
Children who have difficulty distinguishing subtle differences in sounds will misunderstand what someone is saying and respond incorrectly. Words that sound alike are often confused – blue and blew or ball and bell.
Some children have difficulty with auditory figure-ground and cannot process sound input as fast as expected. It is called “auditory lag.”
Once the information coming into the brain is registered, it has to be understood. It is all about inferring meaning from the context in which a word is used, both a general meaning and a specific meaning. For example, the dog and your dog have very different meanings. The ability to draw general applications from specific words to attach subtle shading to basic meanings of words is referred to as “abstract thinking.”
Once information is recorded in the brain and laced in the right sequence, one must be able to infer meaning. Most learning disabled children have only minor difficulties in this area. Abstraction – the ability to derive the correct general meaning from a particular word or symbol – is a very basic intellectual task.
Short-term memory is the process by which you hold on to information as long as you are concentrating on it. Long-term memory refers to the process by which you can store information that you have repeated often enough. If your child has a memory disability, it is most likely a short-term one. A short-term memory disability can occur with information learned through what one sees – visual short-term memory disability – or with information learned through what one hears – auditory short-term memory disability. Often the two are combined.
Information comes out of the brain either by the means of works – language output – or through muscle activity, such as writing, drawing – motor output. A child or adolescent may have a language disability or motor disability.
Two forms of language are used in communication, spontaneous language and demand language. Spontaneous language is used in situations where you initiate whatever is said. This situation contains the luxury of choosing the subject and taking the time to organise your thoughts.
Children with specific language disability usually have no difficulty with spontaneous language. They do, however, often have issues with demand language. A young child may initiate all kinds of conversation, but when they are put into a situation that demands a response, the child may seem confused.
If a child has difficulty using large muscle groups, this is called a gross motor disability. Difficulty in performing tasks that require many muscles to work together in an integrated way is a fine motor disability,
The most common form of fine motor disability shows up when the child begins to write. The problem lies in an inability to get the many muscles in the dominant hand to work together as a team. Children and adolescents with this “written language” disability have slow and poor handwriting. A typical expression of this problem is, “My hand doesn’t work as fast as my head is thinking.”
When a child has a visual perceptual problem, the brain, which has incorrectly recorded or processed information, will probably misinform the muscles during activities that require eye-hand coordination. This is referred to as a visual motor disability.