What is a learning disability?
When the central nervous system, the brain and spinal cord which control bodily functions such as sight, speech, and movement does not work perfectly, the child may have difficulty performing certain tasks. This may first become apparent when the child does not reach the normal developmental milestones at the appropriate age. She may have been slow in learning to hold her head up, or in talking or walking. Or she may not show any symptoms until later when she is unable to do the things other children her age find possible, although you should always keep in mind the fact that children develop at different rates. (See Chapter 5 for a guide to normal development.)
Possibly because of their relatively immature neurological development, far more boys than girls are affected. Minimal brain dysfunction (M.B.D.) is the term most often used to describe childen who have problems in processing information, even though they have at least average or above average intelligence. Learning disabilities associated with minimal brain dysfunction may affect only certain skills, or could be more generalised with an all-over lag in performance. Behavioural problems, particularly hyperactivity, are common; while emotional adjustment, although initially normal, often deteriorates due to frustration and loss of self-esteem.
The term, minimal brain dysfunction is misleading, because the brain itself does not show anatomical differences. It is thought that the problem lies in how information is processed. Slow maturation of the nervous system and defective filtering of information are considered part of the problem, making these children easily distracted because of their inability to screen out any irrelevant messages the brain receives.