Dyslexia

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Dyslexia refers to any reading difficulty not associated with obvious problems such as bad eyesight. Common dyslexias include the inability to name letters, to read words or sentences, or to recognize words directly even though they can be sounded out. Most theories focus on nonprimary areas in the frontal lobe and the temporal lobe. (Galaburda, 1994; Rosenzweig, Lieman, et al., 1996;) Recent studies have linked several forms of dyslexia to genetic marker (Grigorenko, 2001; Grigorenko etal., 1997; Grigorenko, Wood, Meyer, & Pauls, 2000).

It is said to be a neurological disorder with biochemical and genetic markers. Dyslexia was originally defined as a difficulty with reading and writing that could not be explained by general intelligence. One diagnostic approach is to compare their ability in areas such as reading and writing to that which would be predicted by his or her general level of intelligence.

The term was coined in 1884 by R. Berlin <ref>Berlin, R. (1884). Uber Dyslexie. Archiv fur Psychiatrie, 15, 276-278.</ref>. People are diagnosed as dyslexic when their reading problems cannot be explained by a lack of intellectual ability, inadequate instruction, or sensory problems such as poor eyesight.

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Dyslexia International definitions.

Dyslexia is widely accepted in the international community as a learning disability. The most widely accepted theories argue that the dyslexic individual has biological traits that differentiate them from other individuals.

The World Health Organization (WHO)

A disorder manifested by difficulty learning to read, despite conventional instruction, adequate intelligence and sociocultural opportunity. It is dependent upon fundamental cognitive disabilities which are frequently of constitutional origin". ICD-10, The International Statistical Classification of Diseases and Related Health Problems, tenth revision ICIDH-2, The International Classification of Impairments, Activities, and Participation

US National Institute of Child Health and Human Development (NICHD) / International Dyslexia Association

Defines Dyslexia as a specific learning disability of neurological origin. Characterized with difficulties with accurate and/or fluent word recognition, spelling and decoding abilities.

Canadian Government

The Government of Canada’s Health Portal links its description to the Bchealthguide web site using their definition. Dyslexia is defined here with a difficulty with the alphabet, reading, writing, and spelling ins spite of normal to above average intelligence, conventional teaching, and adequate sociocultural opportunity. Dyslexia is thought to be genetic and hereditary. Dyslexia is not caused by poor vision. Dyslexia is diagnosed following psychological and educational tests that determine language and other academic abilities, IQ and problem-solving skills, and is only diagnosed if the reading disability is not a result of another condition.

The British Dyslexia Association

Dyslexia is a difference in the brain area that deals with language. It affects the underlaying skills that are needed for learning to read, write and spell. Brain imaging techniques show that dyslexic people process information differently.In a report on the House of Lords Dyslexia debate which took place on Wednesday 7 December is now available the Government confirms dyslexia is not a myth.

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Variations and related disorders

Dyslexia is a learning disorder. Its underlying cause may be neurological in nature, but from there, the systems involved play out into visual, language, etc. FMRI (Functional Magnetic Resonance Imaging) has been used to demonstrate differences in the dyslexic brain patterns, but much research still needs to be done to apply this information.

In addition to the typical forms of dyslexia, there are numerous related disorders:

  • Auditory Processing Disorder is the cause of the phonological problems that many dyslexics experience, and causes problems in the auditory memory or working memory and auditory sequencing issues. Many with Auditory Processing issues develop visual learning coping strategies, and benefit from a Whole Language approach to reading, and using multi-colored or multi-formatted text.
  • Semantic dyslexia - a form of dyslexia characterized by an inability to properly attach words to their meanings in reading and/or in speech.
  • Scotopic sensitivity syndrome - a form of dyslexia which makes it very difficult for a person to read black text on white paper, particularly when the paper is slightly shiny.
  • Dyspraxia - a neurological disorder characterised by a marked difficulty in carrying out routine tasks involving balance, fine-motor control, and kinesthetic coordination.
  • Verbal Dyspraxia - a neurological disorder characterised by marked difficulty in the use of speech sounds, which is the result of an immaturity in the speech production area of the brain.
  • Dysgraphia - a neurological disorder characterised by distorted and incorrect writing.
  • Dyscalculia - a neurological disorder characterised by a problem with learning fundamentals and one or more of the basic numerical skills. Often people with this disorder can understand very complex mathematical concepts and principles but have difficulty processing formulas and even basic addition and subtraction.
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Facts and statistics

Between 5 and 15 percent of the population can be diagnosed as suffering from various degrees of dyslexia. As previously mentioned, dyslexia can be substantially compensated for with proper therapy, training and equipment.

Most researchers agree that there is a fairly even gender balance amongst dyslexics, and that the fact that it is reported more in males is because of selection factors and bias.

Dyslexia's main manifestation is a difficulty in developing reading skills in elementary school children. Those difficulties result from reduced ability to associate visual symbols with verbal sounds. While motivational factors must also be reviewed in assessing poor performance, dyslexia is considered to be an inborn trait and rarely arises from environmental factors after the brain has matured beyond its especially plastic condition during infancy.

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Physiology and treatment

Only traditional educational remedial techniques have any record of improving the reading ability of those diagnosed with dyslexia <ref>Learning Disabilities, Dyslexia, and Vision: A Subject Review A report from American Academy Of Pediatrics reporting the complete lack of evidence for a link between visual problems and learning difficulties. Essentially, coloured lenses and other visual gimmicks and exercises should be avoided according to this report.</ref>. There is no evidence that coloured lenses, any visual training, or similar proposed treatments are of any use. Anecdotal reports of success can be explained by other factors.

Even a few weeks of intense phonological training (often involving breaking down and rearranging sounds to produce different words) can help noticeably improve reading skills. The earlier the phonological regimen is taken on, the better the overall result. Advanced brain scans could identify children at risk of dyslexia before they can even read, although it is thought that simple tests of balance could do the same. It is claimed that many of the underlying causes of dyslexia are of a genetic nature and that there are no cures, only strategies to work around the causes of a persons dyslexia, however these two claims are disputed.

It had been believed that keeping a child active, perhaps by giving them housework, or performing physical exercises, would help with dyslexia. However, this is false (Wilsher 2002 - Dyslexia, Volume 8, Number 2, April/June 2002, pp. 116-117(2)). There is no scientific evidence in support of this theory.

Researchers studying the brains of dyslexics have found that during reading tasks, dyslexics show reduced activity in the left inferior parietal cortex. It is anecdotally claimed that it is not that uncommon for dyslexics who have trained themselves to cope with their affliction, to develop uncannily efficient visual memories which aid in reading and comprehending large quantities of information much faster than is typical. Commonly dyslexics show 10 times more brain activity when reading. Sometimes, depending of the type and extent, also writing, listening and speaking. However, increased brain activity is not necessarily a sign of better processing. Conversely, some dyslexics may show a natural dislike of reading and, in consequence, compensate by developing unique verbal communication skills, inter-personal expertise, and leadership skills.

In 1979, anatomical differences in the brain of a young dyslexic were documented. Albert Galaburda of Harvard Medical School noticed that the language center in a dyslexic brain showed microscopic flaws known as ectopias and microgyria. Both affect the normal six-layer structure of the cortex. An ectopia is a collection of neurons that have pushed up from lower cortical layers into the outermost one. A microgyrus is an area of cortex that includes only four layers instead of six.

These flaws affect connectivity and functionality of the cortex in critical areas related to auditory processing and visual processing. These and similar structural abnormalities may be the basis of the inevitable and hard to overcome difficulty in reading.

A nother study regarding genetic regions on chromosomes 1 and 6 have been found that might be linked to dyslexia. Presenting the argument, dyslexia is a conglomeration of disorders that all affect similar and associated areas of the cortex.

Some studies have concluded that speakers of languages whose orthography has a strong correspondence between letter and sound (e.g. Korean and Italian) have a much lower incidence of dyslexia than speakers of languages where the letter is less closely linked to the sound (e.g. English and French). <ref>News Briefs: Scientists Say Severity of Dyslexia Depends on Language</ref>


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Characteristics

Ronald D. Davis places forth the argument that most dyslexics will exhibit about 10 of the following traits and behaviors. These characteristics can vary from day-to-day or minute-to-minute. The most consistent thing about dyslexics is their inconsistency. Symptoms increase dramatically with confusion, time pressure, emotional stress, or poor health. This may vary according to which of the suggested underlying causes of dyslexia affect the individual dyslexic

dyslexic.<ref>37 Common Characteristics of Dyslexia © 1992 by Ronald D. Davis.</ref>

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General

  • Appears bright, highly intelligent, and articulate but unable to read, write, or spell at grade level.
  • Labelled lazy, dumb, careless, immature, "not trying hard enough," or "behavior problem."
  • Isn't "behind enough" or "bad enough" to be helped in the school setting.
  • High in IQ, yet may not test well academically; tests well orally, but not written.
  • Feels dumb; has poor self-esteem; hides or covers up weaknesses with ingenious compensatory *strategies; easily frustrated

and emotional about school reading or testing.

  • Talented in art, drama, music, sports, mechanics, story-telling, sales, business, designing, building, or engineering.
  • Seems to "Zone out" or daydream often; gets lost easily or loses track of time.
  • Difficulty sustaining attention; seems "hyper" or "daydreamer."
  • Learns best through hands-on experience, demonstrations, experimentation, observation, and visual aids.
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Vision, reading, and spelling

There is no scientific evidence that a relationship exists between reading failure and perceptual ability or that visual training provides effective treatment. [1].

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Hearing and speech

  • Has extended hearing; hears things not said or apparent to others; easily distracted by sounds.
  • Difficulty putting thoughts into words; speaks in halting phrases; leaves sentences incomplete; stutters under stress; mispronounces long words, or transposes phrases, words, and syllables when speaking.
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Writing and motor skills

  • Trouble with writing or copying; pencil grip is unusual; handwriting varies or is illegible.
  • Clumsy, uncoordinated, poor at ball or team sports; difficulties with fine and/or gross motor skills and tasks; prone to motion-sickness.
  • Can be ambidextrous, and often confuses left/right, over/under.
  • May write in "mirror writing" (writing that appears backwards, but can be read when reflected in a mirror)
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Math and time management

  • Has difficulty telling time, managing time, learning sequenced information or tasks, or being on time.
  • Shows dependence on finger counting and other tricks when doing math; knows answers, but can't do it on paper.
  • Can count, but has difficulty counting objects and dealing with money.
  • Can do arithmetic, but fails word problems; when doing math must see the big picture before the detail.
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Memory and cognition

  • Excellent long-term memory for experiences, dates, names, locations, and faces.
  • Poor memory for sequences, facts and information that have not been experienced.
  • Thinks primarily with images and feeling, not sounds or words (little internal dialogue).
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Behavior, health, development and personality

  • Extremely disorderly or compulsively orderly.
  • Can be class clown, trouble-maker, or too quiet.
  • Had unusually early or late developmental stages (talking, crawling, walking, tying shoes).
  • Prone to ear infections; sensitive to foods, additives, and chemical products.
  • Extremely sensitive to human contact- when another person touches them they may feel very "uncomfortable."
  • Can be an extra deep or light sleeper; bedwetting beyond appropriate age.
  • Unusually high or low tolerance for pain.
  • Strong sense of justice; emotionally sensitive; strives for perfection.
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Public support

In the United States, Canada and in the United Kingdom, some people say that there is a lack of adequate support and a general lack of interest in the learning disabilities of children in public schools. This has recently led to legal action by private parties against public schools in the United States and state schools in the United Kingdom. In English law, the recent case of Skipper v Calderdale Metropolitan Borough School (2006) EWCA Civ 238 the Court of Appeal applied Phelps v London Borough of Hillingdon (2001) 2 AC 619 as the landmark case on the failure to diagnose dyslexia (see duty of care in English law), and to hold that the appellant could pursue her claim against her school for humiliation, lost confidence, and lost self-esteem, and for loss of earnings following its failing to diagnose and treat her dyslexia despite the fact that, as Latham LJ. says at para 29:

"The extent to which her dyslexia could have been ameliorated or provided for will always remain uncertain, as will the extent to which that would have affected her performance in public examinations; the evidence that we have includes material to suggest that she, not surprisingly, reacted adversely to the break-up of her parents marriage when she was 15, in other words at a critical time in her education. Whether any improvement in her examination results would have led to her life taking a significantly different course will also be a matter for some speculation."

Some charitable organizations like the Scottish Rite Foundation have undertaken the task of testing for dyslexia and making training classes and materials available for teachers and students. [2] [3] [4]

In England and Wales, the failure of schools to diagnose and provide remedial help for dyslexia following the House of Lords decision in the case of Pamela Phelps has created an entitlement in students with dyslexia in Higher Education to receive support funded via the Disabled Students Allowance. Support can take the form of IT equipment (software and hardware) as well as personal assistance, also known as non-medical helper support. Dyslexic students will also be entitled to special provision in examinations such as additional time to allow them to read and comprehend exam questions.

The British Disability Discrimination Act also covers dyslexia.

"In some cases, people have 'coping strategies' which cease to work in certain circumstances (for example, where someone who stutters or has dyslexia is placed under stress). If it is possible that a person's ability to manage the effects of the impairment will break down so that these effects will sometimes occur, this possibility must be taken into account when assessing the effects of the impairment." — Paragraph A8, Guidance to the Definitions of Disability

Many doctors and teachers diagnose students with Attention Deficit Disorder rather than dyslexia. Of all the conditions that can mimic, mask or co-exist with ADD, dyslexia is probably the most well known. It is also one of the most misunderstood. Dyslexia is a learning disability that affects 17-20% of school age children according to the Department of Health, Education and Welfare. Like ADD, the dyslexic mind functions differently than others. Dyslexic children, like ADD children, tend to be above average intelligence, if not gifted. But they have specific difficulties with words. They have difficulty recalling words, even words they are familiar with. They also have difficulty with sequencing. Letters and syllables can become inverted (like "aminal") as can entire words. ("Come here over.") The child may have trouble distinguishing between the letters "b," "d," "q" and "p."

"The Dyslexia Myth" a documentary presented five views about the future of the term Dyslexia, based on the argument that the common understanding of Dyslexia is false. However it should be noted that the British government has confirmed Dyslexia is not a myth as reported by the British Dyslexia Association. This was concluded in the House of Lords debate on Dec 7th of 2005.


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Bibliography

  • de Lacoste-Utamsing, C., and Holloway, R., Sexual Dimorphism in the Human Corpus Callosum, Science, Vol 216, 1982.
  • Dennis, M., Impaired Sensory and Motor Differentiation with CC Agenesis: A Lack of Callosal Inhibition during Ontogeny? Neuropsychologia, vol 14 p. 455-469, 1976.
  • Duffy, F., Denkla, M., Bartels, P., and Sandini, G., Dyslexia: Regional Differences in Brain Electrical Activity by Topographic Mapping, Annals of Neurology, vol 7 #5, 1980
  • Ettlinger, G., Blakemore, C. B., Milner, A. D., and Milner J., Agenesis of the Corpus Callosum: A behavioral Investigation, Brain, vol 75, 1972.
  • Ferriss, G. S., and Dorsen, M., Agenesis of the Corpus Callosum: Neuropsychological Studies, Cortex, vol2, #2, 1975.
  • Gazzaniga, M. S., Cognitive and Neurologic Aspects of Hemispheric Disconnection in the Human Brain, Discussions in Neurosciences, vol 4, #4, FESN, 1978.
  • Gazzaniga, M., Consistency and Diversity in Brain Organization, Annals of the New York Academy of Sciences, vol 299, Ps 415-424, 1977.
  • Gladstone, M., and Best, C. T., Developmental Dyslexia: The Potential Role of Interhemispheric Collaboration in Reading Acquisition, Hemispheric Function and Collaboration in the Child, Ed., Catherine Best, Academic Press 1983.
  • Gross, K., Rothenberg, S., Schottenfield, S., and Drake, C., Duration Thresholds for Letter Identification in Left and Right Visual Fields for Normal and Reading-Disabled Children, Neuropsvchologia, vol 6, 1978.
  • Gross-Glenn, K., and Rothenberg, S., Evidence for Deficit in Interhemispheric Transfer of Information in Dyslexic Boys, International Journal of Neuroscience, vol 24, 1984.
  • Haggerty, R., and Stamm, J. S., Dichotic Auditory Fusion Levels in Children with Learning-Disabilities, Neuropsychologia, vol 16, 3, 1978.
  • Harris, A. J., Lateral Dominance and Reading Disability, Journal of Learning Disabilities, vol 12, #5 1979.
  • Horowitz, B., Rumsey, J.M. and Donohue, B.C., Functional Connectivity of the Angular Gyrus in Normal Reading and Dyslexia, Proceedings of the National Academy of Sciences, vol 95, July 21, 1998
  • Hynd, G.W. et al., Dyslexia and Corpus Callosum Morphology, Archives of Neurology, vol 52, Jan., 1995
  • Shaywitz, S. E. et a., Evidence that Dyslexia may represent the Lower Tail of a Normal Distribution of Reading Ability, The New England Journal of Medicine, vol 326, Ps 145-150, 1992.
  • Snowling, M.J. (2000). Dyslexia. Blackwell Publishing: ISBN 0631205748
  • Channel 4. "Dispatches the Dyslexia Myth" http://www.channel4.com/news/microsites/D/dyslexia_myth/dyslexia.html
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See also

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External links

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Associations and organizations

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Tools and other information

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References


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