Defects in specific writing difficulty
The exact nature of the writing difficulty varies from child to child. The commonest problems are motor planning difficulties and visual perception deficit.
Motor planning difficulties
In this problem the child can produce any of the actions involved in forming a letter in isolation, but the part of the brain responsible for ensuring that these actions are carried out in an uninterrupted sequence does not work properly. This is a well-recognized problem, known as dyspraxia; it is also seen in adults who have sustained damage to certain parts of the brain. It may be associated with generalized clumsiness and with speech problems (verbal dyspraxia).
Visual perception deficit
Whereas motor planning difficulties affect the way that letters are produced, visual perception deficit affects the way in which they are perceived. Children with this deficit have an impairment in the way in that they perceive the shape and configuration of letters. This is not due to a disorder of the eyes, but to a problem with the way the brain interprets the messages transmitted from the eyes.
Such children will be shown to have difficulties on tests of visual perception. They often go about making letters in an extremely complicated and uncomfortable way. They may superimpose letters, write them the wrong way round, or leave large gaps between letters.