Historical Perspective |
Before the National Institutes of Health began their research in the 1980's, the only definition of dyslexia was an exclusionary one. If a child's difficulty with reading could not be explained by low intelligence, poor eye sight, poor hearing, inadequate educational opportunities, or any other problem, then the child must be dyslexic.
That definition was not satisfactory to parents, teachers, or researchers. So here are three different definitions in use today.
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Simple Definition |
Dyslexia is an inherited condition that makes it extremely difficult to read, write, and spell in your native language—despite at least average intelligence.
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Revised definition from the International Dyslexia Association |
Dyslexia is a neurologically-based, often familial, disorder which interferes with the acquisition and processing of language. Varying in degrees of severity, it is manifested by difficulties in receptive and expressive language, including phonological processing, in reading, writing, spelling, handwriting, and sometimes in arithmetic.
Dyslexia is not the result of lack of motivation, sensory impairment, inadequate instructional or environmental opportunities, or other limiting conditions, but may occur together with these conditions.
Although dyslexia is lifelong, individuals with dyslexia frequently respond successfully to timely and appropriate intervention.
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Research definition used by the National Institutes of Health |
Dyslexia is a specific learning disability that is neurological in origin.
It is characterized by difficulties with accurate and/or fluent word recognition, and by poor spelling and decoding abilities.
These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction.
Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge.
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Learning Disability |
Learning Disability is not a specific term; it is a category containing many specific disabilities, all of which cause learning to be difficult. The following definition of "learning disability" is used for legislative, financial, and educational purposes only. It is NOT a definition of dyslexia, which is one specific learning disability.
The term 'learning disability' means a disorder in one or more of the basic processes involved in understanding spoken or written language. It may show up as a problem in listening, thinking, speaking, reading, writing, or spelling or in a person's ability to do math, despite at least average intelligence.
The term does not include children who have learning problems which are primarily the result of visual, hearing, or physical handicaps, or mental retardation, or emotional disturbance, or of environmental, cultural, or economic disadvantage.
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Cause of Dyslexia |
Dyslexia is an inherited condition. Researchers have determined that a gene on the short arm of chromosome #6 is responsible for dyslexia. That gene is dominant, making dyslexia highly heritable. It definitely runs in families.
Dyslexia results from a neurological difference; that is, a brain difference. People with dyslexia have a larger right-hemisphere in their brains than those of normal readers. That may be one reason people with dyslexia often have significant strengths in areas controlled by the right-side of the brain, such as artistic, athletic, and mechanical gifts; 3-D visualization ability; musical talent; creative problem solving skills; and intuitive people skills.
In addition to unique brain architecture, people with dyslexia have unusual "wiring". Neurons are found in unusual places in the brain, and are not as neatly ordered as in non-dyslexic brains.
In addition to unique brain architecture and unusual wiring, f/MRI studies have shown that people with dyslexia do not use the same part of their brain when reading as other people. Regular readers consistently use the same part of their brain when they read. People with dyslexia do not use that part of their brain, and there appears to be no consistent part used among dyslexic readers.
It is therefore assumed that people with dyslexia are not using the most efficient part of their brain when they read. A different part of their brain has taken over that function.
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Phonemic Awareness |
Quotes from prominent NIH researchers:
"The lack of phonemic awareness is the most powerful determinant of the likelihood of failure to learn to read."
"Phonemic awareness is more highly related to learning to read . . . than tests of general intelligence, reading readiness, and listening comprehension."
"Phonemic awareness is the most important core and causal factor separating normal and disabled readers."
NIH research has repeatedly demonstrated that lack of phonemic awareness is the root cause of reading failure. Phonemes are the smallest unit of SPOKEN language, not written language.
Children who lack phonemic awareness are unable to distinguish or manipulate SOUNDS within SPOKEN words or syllables. They would be unable to do the following tasks:
- Phoneme Segmentation: what sounds do you hear in the word hot? What's the last sound in the word map?
- Phoneme Deletion: what word would be left if the /k/ sound were taken away from cat?
- Phoneme Matching: do pen and pipe start with the same sound?
- Phoneme Counting: how many sounds do you hear in the word cake?
- Phoneme Substitution: what word would you have if you changed the /h/ in hot to /p/?
- Blending: what word would you have if you put these sounds together? /s/ /a/ /t/
- Rhyming: tell me as many words as you can that rhyme with the word eat.
If a child lacks phonemic awareness, they will have difficulty learning the relationship between letters and the sounds they represent in words, as well as applying those letter/sound correspondences to help them "sound out" unknown words.
So children who perform poorly on phonemic awareness tasks via oral language in kindergarten are very likely to experience difficulties acquiring the early word reading skills that provide the foundation for growth of reading ability throughout elementary school.
Phonemic awareness skills can and must be directly and explicitly taught to children who lack this awareness.
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Phonological Processing and Phonics |
Phonemic awareness must exist or be explicitly and directly taught BEFORE phonics instruction begins. Otherwise, the phonics instruction will not make sense to the dyslexic child.
Phonological processing refers to understanding of sounds used in our language, ranging from big chunks of sound (words), to smaller chunks (syllables) and eventually to phonemic awareness (every sound within a syllable). Both phonemic awareness and phonological processing are auditory processing skills. Therefore, they can (and should) be taught before letters are introduced.
The goal of teaching phonics is to link the individual sounds to letters, and to make that process fluent and automatic, for both reading and spelling. In other words, phonics teaches students symbol-to-sound and sound-to-symbol.
But for phonics to work, a student must first have solid phonological processing and phonemic awareness. |
There are four main challenges for a dyslexic child:
1. Spelling
2. Sentence punctuation
3. Handwriting
4. Sequencing ideas
1. Spelling
Visual memory weaknesses present particular challenges. This weakness prevents a child or teenager from having a strong memory of what many common words look like. You can compare this to your own visual memory of what the Statue of Liberty looks like - you probably have a clear picture in your mind.
Dyslexic children can learn to work out the spellings of words that follow a logical pattern of letter sounds (like 'c-a-t' and 's-i-n-g'). The best help for a dyslexic child is to use phonics-based teaching of spelling . However, the spellings of words with little relation to their sounds - like 'said' and 'ought' - are particularly difficult to remember. They do not sound like the letter-sounds from which they are spelt.
In some languages, like Italian, the spellings can be worked out from their letter-sounds. So, a sentence like:
La mia madre desidera andare all'isola.
(My mother wants to go to the island)
is not too hard to spell once you know the rules. However, to spell the English word 'mother' from its letter-sounds is not easy: you would think that the beginning of moth|er was a flying insect! The word 'island' looks like 'is' 'land' and the letter sounds do not create the word 'island'.
Other words like 'where', 'here', 'are', 'there', etc. are equally impossible to spell from the sounds of their letters. (These illogical spellings came about because of the complex history of the English language, which has been built up from other languages over the centuries.)
One group of spellings causes particular difficulties for dyslexic writers:
any ('eny')
many ('meny')
does ('dus')
said ('sed')
they ('thay')
because ('becos')
island ('iland')
eyes('ies')
friend ('frend')
enough ('enuff')
These tricky words can be learned as a 'mnemonic' by dyslexic children. 'Because', for example, can be remembered from the first letters of the 'silly' sentence: 'Big Elephants Can Add Up Sums Easily'. The word 'any' can be remembered by using the 'silly sentence 'Ants Never Yawn'. A useful book which provides mnemonics for these words is 'Mnemonics' from Tregear Books.
Dyslexic children and teenagers can be helped if teachers write the spellings of words which most children will use on the board while discussing the topic with them. For example, if the children were to write about 'My trip', the teacher could put such words on the board as:
decided
miles
camping
mountain
lake
mosquito
campfire
etc.
Telling dyslexic children to check spellings in a dictionary is not helpful. To find a word in a dictionary, you have to know how the word is spelt in the first place! However, spell-checkers can make a big difference (and are seen as being fun and trendy!).
2. Sentence punctuation
Sentence punctuation means putting upper-case or capital letters at the start, and periods or full stops at the end, of each sentence. You will often notice dyslexic children omitting these crucial markers of how the passage reads.
An easy exercise to teach this is to take a passage of about five or six sentences which a dyslexic child can read without difficulty, and type it out, omitting the upper-case letters and periods. Children will soon see how hard it is to make sense of the passage, and they can be asked to punctuate the passage into sentences. If repeated a number of times, children will become proficient at using sentence punctuation themselves.
Another activity which works well is to say a couple of sentences to a child, and ask how many sentences you said. For example, say: 'I got into the car yesterday. I found the map I had been looking for.' (two sentences). Say: 'I went home last night and cooked myself a meal.' (one sentence). The child will soon come to realize that the word 'and' can link two ideas into one sentence.
3. Handwriting
Some dyslexic children experience difficulty memorizing the sequence of movements which make up the writing of each letter. This can lead to uneven handwriting, and, if severe, may be described as 'dysgraphia'.
They may also find it hard to remember which way round certain letters go (like b/d, 9/p, p/q. c, z, j, g, and others).
The following approaches can help:
- When assessing a dyslexic child's original writing, it is important to ignore the poor spelling and handwriting, and to grade on the content rather than the handwriting.
- The best help for improving handwriting and memorizing spellings is to teach dyslexic children cursive handwriting.
In view of their difficulties with handwriting, dyslexic children should be allowed to do homework assignments on a word processor at home, and to bring in the print-out. As this can be spell-checked, and usually looks attractive, it can help to re-build their self-confidence. Some schools allow dyslexic children to do their written work in class on an inexpensive laptop computer (from an educational supplier) with a spell-checker, and take it to the Special Services/Special Needs department at recess/break times to print out their work..
(Comparison of the handwriting of a dyslexic child with that of a child who is not dyslexic.)
4. Sequencing ideas
Telling a story in the right order or explaining what happened can cause problems. Dyslexic children, teenagers and students are often unaware of the need to sketch out a rough outline of an essay before actually writing it. This can look like this:
1. Introduction - how we decided to go on a trip.
2. What we took with us.
3. Journey to the mountains.
4. Setting up camp by a lake.
5. Getting lost on the first day.
6. Two million mosquitoes at night!
6. Cooking a meal on the camp fire.
7. Singing songs on our journey home.
8. Conclusion - like to go again, but with a mosquito net!
With this plan on a sheet of paper, a dyslexic child can then write a paragraph about each part of the story, confident in the knowledge that each section of the story will be in the right order. Although time-consuming at first, thus procedure leads to confident essay-writing over the years.
For a university student, a plan like this can re-build their confidence in their ability to write an essay which argues a point coherently. Once the plan is written, they only have to fill out each section.
John Bradford
June 2003
John Bradford is Director of Direct Learning.
Dslexia- What is Dyslexia?- Does My Child Have Dyslexia- Testing for Dyslexia 
