Myomancy ADHD, Dyslexia and Autism

The Different Types of Dyslexia

If you browse through the dyslexia web-sites and forums you will notice people referring to Visual Dyslexia, Auditory Dyslexia, Phonological Dyslexia and Orthographic Dyslexia but do these terms mean anything? Before we can answer that question, we must define what we mean by dyslexia and there are two schools of thought exist about this.

Many academics give dyslexia a literal meaning based on the etymology. ‘Dys’ meaning wrong or problematic (e.g. dysfunctional) and ‘lexia’, pertaining to words and letters. So literally in means a problem with words. So anyone who has a problem reading, for whatever reason, has dyslexia.

On the other side of the issue are parents of dyslexics and dyslexic adults. They use dyslexia to refer to a range of symptoms that includes problems with reading, writing and spelling plus other problems such as poor memory and a lack of physical coordination.

In these studies mentioned in this article the focus is on the academic / literal meaning of dyslexia being just a reading problem. This is because most studies only tested reading ability and did not do a broad sweep of the child’s abilities. It also worth noting that this article focuses on development dyslexia and not acquired dyslexia. Development dyslexia is ‘normal’ dyslexia, where the problem manifests itself through the entire life of the individual. Acquired dyslexia happens when the individual has had normal reading abilities but because of brain damage caused by accidents, stokes or disease they have lost their normal abilities.

The first attempt to sub-divide dyslexia in to different types was the idea of ‘surface’, ‘phonological’ and ‘double-deficit’ dyslexia by Marshall and Newcombe in 1973. The symptoms of Surface Dyslexia relate to making mistakes where the rules of English are not consistent. For example, pretty is read as if it rhymed with “jetty”, and bowl is read as if it rhymed with “howl”. Phonological Dyslexia represents a failure to grasp the phonic nature of English. Individuals with it have great problems reading new or nonsense words because they cannot grasp the link between the individual sounds or phonemes and letters on the page. Where an individual has both types of dyslexia, it is called Double-Deficit Dyslexia.

Since these different types of dyslexia were proposed there has been a lot of research and debate on them. Various questions about the original research and how it was done have been raised. Some studies have shown that Double-Deficit Dyslexia is the most common type and only having one type of dyslexia, surface or phonological, is rare. Other studies have suggest that Surface Dyslexia only represents a child who is simply behind in their reading and will catch up with sufficient teaching whereas Phonological Dyslexia represent a deep seated neurological problem.

Auditory Dyslexia and Visual Dyslexia are both fruits of the magnocellular theory of dyslexia. This theory proposes that dyslexics have neurological have a weakness in the magnocellular cells of their thalamas. This area of the brain is used for rapid processing of visual and auditory information. Numerous studies have shown that dyslexics do have weaknesses in their visual and auditory processing but not all children have them to the same degree. So a child with poor hearing skills but with average visual skills might be diagnosed with Auditory Dyslexia where as poor visual but average hearing will be diagnosed as Visual Dyslexia.

The final type of dyslexia is Orthographic Dyslexia. Orthography is the set of symbols or letters that make up a language. In English this is the 26 letters of the alphabet whilst in Japanese it covers thousands of different symbols. Orthographic Dyslexia therefore relates to problems identifying and manipulating letters in reading, writing and spelling. This subtype of dyslexia has not been researched much and whilst most people in the field recognise that dyslexics have an orthographic problem there is too little evidence to say whether it constitutes a sub-type of dyslexia.

The usefulness of splitting dyslexia in to different types is debatable. First there is no strict definition of what each type is. Different researchers and educationalists use the same phrases to describe subtly different sets of symptoms. Secondly does it matter whether a child has Auditory Dyslexia or Visual Dyslexia if they are treated in the same way? Nine times out of ten, schools will teach all dyslexic children to read the same way, using phonics or multi-sensory methods.

Previously on Myomancy: Reading, Phonetics and Dyslexia; Light & Sound Sensitivity Effects Readers; Dyslexia Not a Myth

Research: On the Bases of Two Subtypes of Developmental Dyslexia [ PDF ]; Varieties of developmental dyslexia ; Reliability of Phonological and Surface Subtypes in Developmental Dyslexia: A Review of Five Multiple Cases Studies; Theories of developmental dyslexia: insights from a multiple case study of dyslexic adults; To see but not to read;the magnocellular
theory of dyslexia [ PDF ]

Related posts:

  1. Dyslexia and Eye Tracking Problems
  2. Light & Sound Sensitivity Effects Readers
  3. Rhythm and Dyslexia
  4. Dyslexia Not a Myth
  5. Dyslexia and fMRI

Comments on: The Different Types of Dyslexia

  1. This website really helped me with my school research paper.

  2. My child has a reading disability. His visual reading does not connect immediately to his brain. He takes few seconds to recognise words & he takes time to write. Kindly advice

  3. I was diagnosed as a child as dyslexic. I don’t feel that I struggle with dyslexia except in my organizational skills and at times feeling overwhelmed with a task and not knowing where or how to begin. Is there a program that can help me with this?

  4. Dear Sirs;
    My wife is 54 years old and has never been diagnosed as dyslexic until we were married in 2006. I recognized the symptoms and went on line to find our that I was right. Her entire family has treated her with scorn all her life as did her late husband. She has auditory dyslexia. She hears things without understanding what has been said. She also is very disorganized. Her father says that she has been “stupid” all her life. This stigma has caused a lot of depression and anxiety as you can imagine. Do you have a resource that could help her?
    Jim Campbell

  5. The Site gave me information on the different types of dyslexia. I always wondered of my son having dyslexia, little did I realize that I too had the similar problems.

  6. How can I(43 year old female) get help for auditory dyslexia. I live in Jackson, MS.

  7. I have a friend that in an evaluation is thought to have surface dyslexia. He reads on grade level, has good decoding and good word attack skills. His spelling is grade level. His processing speed is low low average in symbol search and very low in coding), verbal comprehension is average and perceptual reasoning is very high. I am confused in that if his word attack skills and spelling are good wouldn’t that contradict surface dyslexia? He scored low on reading fluency which as I understood was a bunch of sentences he had to read and give quick responses. Couldn’t his low score on the reading fluency tests be caused by poor processing speed (i.e. he has trouble doing most things quickly because it takes him longer to process). And if so, would this be surface dysgraphia?

  8. I am 24 with a 6 year old son, i am dyslexic i try to act like it doesnt bother me however i am finding it hard. my reading and writing are ok but only when im alone, i have problems reading and writing when around anyone even my son everything become 2as hard.
    I also have a problem with my speach i seem to make up words. i dont say things properly. there are lots of other problems i have become awear of so i think i should ask for help as i dont want to risk slowing my sons learning. Please help

  9. Can you please give me any information of places/program that can help adults in jackson, ms with dyslexia (auditory dyslexia).

    Jennifer

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