Dyslexia is a term which is associated with slow reading in people who are of at least average intelligence. In a broad sense, the term dyslexia means that a person's reading ability is significantly below average. For most people with dyslexia, this would mean very slow reading. For others, it might mean that their reading comprehension is poor. However, the person might be intelligent in other ways. For example, a person with dyslexia might be very astute in learning things through other means, such as listening to lectures, learning through audio tapes or hands-on instruction, or by having conversations with others. However, reading is often very slow for the person with dyslexia, and sometimes it is very painful for those with severe cases.
Dyslexia presents in multiple forms, affecting a variety of aspects of the reading process. As a result, each individual's dyslexia is not precisely the same as another's. For example, an area which is often difficult for the person with dyslexia is reading out loud. This person has trouble connecting the visual form of the word to the sound of the word. This kind of mental processing is called phonological processing. It means there is a problem relating the visual symbol of the word (what you see on the page) to the sound of the word (what you speak and hear). When such a person is asked to read out loud, he (or she) might stumble over the words, might not remember anything of what they just read out loud, and everything might be much worse when they are in front of the class. For the majority of those with dyslexia, the underlying cognitive problem is that of phonological processing; however, it is not the only cause.
There may be other processing problems for the person who has dyslexia besides the principle one noted above, phonological processing. Some people may have a problem in remembering the sound/symbol relationship of the word patterns they see in reading, or they might have a problem with speeded visual processing while their phonological processing is just fine. Others may have a problem putting things in the right order, which is a sequencing problem. One person could have a number of processing problems, and different people may have different combinations of problems—some worse than others.
Dyslexia testing is the best way to determine what is specifically causing a person's learning or reading problems. Once a person's individual diagnosis is determined, appropriate measures can be taken to improve that person's learning habits and reading ability. Effective methods for teaching reading and overcoming academic problems are well-documented and are available at The Brain Clinic.