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Some different reasons for dyslexia

To explain the different  "symptoms" shown by those with dyslexia, researchers have identified different "types," "subtypes," or "sub-components" and their combinations.


The three below show that a phonological explanation alone is not enough, and a more comprehensive approach is necessary to address dyslexia.

Phonological/Dysphonetic/Auditory Dyslexia 

This shows up as being difficult to "sound out" or match sound to letters—decode. Those with poor phonological awareness are best helped by explicit, systematic instruction in phonics, the current main approach in schools.

However, before matching sounds to letters, the individual must recognise that words are made up of small sound units (phonemic awareness), which can be broken down, manipulated and blended, and this needs good memory and auditory processing.

When this doesn't happen it seems that the different parts of the brain needed for good reading are not regulated or synchronised.
Why good auditory processing is necessary for good reading

Rapid Naming Deficit - Dyseidetic/Visual/Dyslexia.

People with this subtype struggle to recognize common words by sight, or they may learn regular words by sight quickly enough but not manage non-regular words.


They need many, many  more repetitions before they can recognize a word instantly without needing to sound it out.

This may be because the brain

  • finds it hard to remember what the word looks like especially words that don’t sound the way they’re spelled. They have difficulty knowing where to put hyphens, capital letters and other punctuation.

  • doesn’t receive the full picture of what the eyes are seeing (poor visual processing) so they may have difficulties learning to form letters or remembering the correct letter sequences so affecting spelling

They may not ever succeed without special support.


See below how good/fast readers integrate more parts of the brain, including the visual cortex. Underactivation of the visual cortex, shows inefficient connections - unsynchronised brain function in Dyslexia

Differences in brain activity with dyslexia

See below how brain overactivation causes inefficient connections, un-synchronised brain function in visual stress

Amen CLinic Scans Differences in brain activity with visual stress

Irlen Syndrome associated with Visual Dyslexia

Amen Clinic Scans

Why good visual processing is necessary for good reading

Double Deficit

You or your child may be struggling with both phonological concerns and rapid naming. You may have learned to decode but still have trouble reading at speed, affecting your comprehension.ffets comprehension. They are the ones who may not easily achieve success.

You will find it harder to improve unless both sets of underlying difficulties are dealt with.

Here's an old but still relevant summary...though some points of view have softened a little...

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