However dyslexia can increase the ability to think and perceive multi-dimensionally and can help further utilize the brain’s ability to alter and create perceptions (Vellutino, 1979). Dyslexia is different from reading difficulties resulting from other causes, such as a non-neurological deficiency with vision or hearing, or from poor or inadequate reading instruction. It is believed that dyslexia can affect between 5 and 10 percent of a given population although there have been no studies to indicate an accurate percentage (Vellutino, 1979).
There are three proposed cognitive subtypes of dyslexia (auditory, visual and attentional), although individual cases of dyslexia are better explained by specific underlying neuropsychological deficits and co-occurring learning disabilities (e. g. attention-deficit/hyperactivity disorder, math disability, etc. ) Reading disability, or dyslexia, is the most common learning disability. Although it is considered to be a receptive language-based learning disability in the research literature, dyslexia also affects one’s expressive language skills.
Adult dyslexics can read with good comprehension, but they tend to read more slowly than non-dyslexics and perform more poorly at spelling and nonsense word reading, a measure of phonological awareness. Dyslexia and IQ are not interrelated as a result of cognition developing on its own. The World Federation of Neurology defines dyslexia as “a disorder manifested by difficulty in learning to read despite conventional instruction, adequate intelligence and sociocultural opportunity”.
The National Institute of Neurological Disorders and Stroke gives the following definition for dyslexia: “Dyslexia is a brain-based type of learning disability that specifically impairs a person’s ability to read. These individuals typically read at levels significantly lower than expected despite having normal intelligence. Although the disorder varies from person to person, common characteristics among people with dyslexia are difficulty with spelling, phonological processing (the manipulation of sounds), and/or rapid visual-verbal responding.
In adults, dyslexia usually occurs after a brain injury or in the context of dementia. It can also be inherited in some families and recent studies have identified a number of genes that may predispose an individual to developing dyslexia (Vellutino, 1979). Other published definitions are purely descriptive or embody causal theories. Varying definitions are used for dyslexia from researchers and organizations around the world; it appears that this disorder encompasses a number of reading skills, deficits and difficulties with a number of causes rather than a single condition (Smythe, Everatt &Salter).
Signs and symptoms Some early symptoms that correlate with a later diagnosis of dyslexia include delays in speech, letter reversal or mirror writing, and being easily distracted by background noise. This pattern of early distractibility is partially explained by the co-occurrence of dyslexia and attention-deficit/hyperactivity disorder. Although each disorder occurs in approximately 5% of children, 25-40% of children with either dyslexia or ADHD meet criteria for the other disorder.
At later ages symptoms can include a difficulty identifying or generating rhyming words, or counting syllables in words (phonological awareness), a difficulty segmenting words into individual sounds, or blending sounds to make words, a difficulty with word retrieval or naming problems (see anomic aphasia), commonly very poor spelling, which has been called dysorthographia or dysgraphia (orthographic coding), whole-word guesses, and tendencies to omit or add letters or words when writing and reading are considered classic signs.
Other classic signs for teenagers and adults with dyslexia include trouble with summarizing a story, memorizing, reading aloud, and learning a foreign language. A common misconception about dyslexia is that dyslexic readers write words backwards or move letters around when reading – this only occurs in a very small population of dyslexic readers. Individuals with dyslexia are better identified by reading accuracy, fluency, and writing skills that do not seem to match their level of intelligence from prior observations (Smythe, Everatt & Salter, 2005).
Cause Theories of dyslexia Research has been trying to find the biological root of dyslexia since it was first identified by Oswald Berkhan in 1881 and the term dyslexia coined in 1887 by Rudolf Berlin. The theories of the etiology of dyslexia have and are evolving with each new generation of dyslexia researchers, and the more recent theories of dyslexia tend to enhance one or more of the older theories as understanding of the nature of dyslexia evolves. (wikipedia. org) Orthographies and dyslexia The complexity of a language’s orthography (i. . its conventional spelling system, see orthographic depth ) has a direct impact upon how difficult it is to learn to read that language. English has a comparatively deep orthography within the Latin alphabet writing system, with a complex orthographic structure that employs spelling patterns at several levels: principally, letter-sound correspondences, syllables, and morphemes. Other languages, such as Spanish, have mostly alphabetic orthographies that employ letter-sound correspondences, so-called shallow orthographies.
It is relatively easy to learn to read languages like Spanish; it is much more difficult to learn to read languages with more complex orthographies such as English (Henry, 2005). Logographic writing systems, notably Japanese and Chinese characters, have graphemes that are not linked directly to their pronunciation, which pose a different type of dyslexic difficulty. From a neurological perspective, different types of writing systems (e. g. lphabetic as compared to logographic writing systems) require different neurological pathways in order to read, write, and spell. Because different writing systems require different parts of the brain to process the visual notation of speech, children with reading problems in one language might not have a reading problem in a language with a different orthography. The neurological skills required to perform the tasks of reading, writing, and spelling can vary between different writing systems.
As a result, different neurological deficits can cause dyslexic problems in relation to different orthographies (Chung, Ho, Chan, Tsang, & Lee, 2006). Cross-cultural prevalence Cross-cultural study of the prevalence of dyslexia is difficult as different scholars and different countries often use different criteria to distinguish the cases of dyslexia in the continuum between the able and delayed readers at schools. According to the existing literature, the prevalence of dyslexia can vary widely between cultures.
For example, Christall reports differences between 1% and 33%. According to some researchers, despite the significant differences between the writing systems, Italian, German and English populations suffer similarly from dyslexia. Wikipedia . org Exacerbating conditions and comorbid disorders Several learning disabilities often occur with dyslexia, but it is unclear whether these learning disabilities share underlying neurological causes with dyslexia (Nicolson &Fewcett, 2009).
These disabilities include: * Dysgraphia – a disorder which expresses itself primarily through writing or typing, although in some cases it may also affect eye–hand coordination, direction- or sequence-oriented processes such as tying knots or carrying out a repetitive task. In dyslexia, dysgraphia is often multifactorial, due to impaired letter writing automaticity, finger motor sequencing challenges, organizational and elaborative difficulties, and impaired visual word form which makes it more difficult to retrieve the visual picture of words required for spelling.
Dysgraphia is distinct from dyspraxia in that dyspraxia is simply related to motor sequence impairment. * Attention deficit disorder – a high degree of co-morbidity has been reported between ADD/ADHD and dyslexia/reading disorders, it occurs in between 12% and 24% of those with dyslexia.  * Auditory processing disorder – A condition that affects the ability to process auditory information. Auditory processing disorder is a listening disability.  It can lead to problems with auditory memory and auditory sequencing.
Many people with dyslexia have auditory processing problems and may develop their own logographic cues to compensate for this type of deficit. Auditory processing disorder is recognized as one of the major causes of dyslexia. * Developmental dyspraxia – A neurological condition characterized by a marked difficulty in carrying out routine tasks involving balance, fine-motor control, kinesthetic coordination, difficulty in the use of speech sounds, problems with short-term memory and organization are typical of dyspraxia.
Neuroanatomy In the area of neurological research into dyslexia, modern neuroimaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) have produced clear evidence of structural differences in the brains of children with reading difficulties. It has been found that people with dyslexia have a deficit in parts of the left hemisphere of the brain involved in reading, which includes the inferior frontal gyrus, inferior parietal lobule, and middle and ventral temporal cortex(Cao et. l. ,2006). Brain activation studies using PET to study language have produced a breakthrough in understanding of the neural basis of language over the past decade. A neural basis for the visual lexicon and for auditory verbal short-term memory components have been proposed, with some implication that the observed neural manifestation of developmental dyslexia is task-specific (i. e. , functional rather than structural) (McCrory, Frith, Brunswick & Price, 2009). Dealing with dyslexia depends on several factors.
Such as the specific writing system of the country, or the specific strengths of the individual; there is no one specific strategy or set of strategies which will work for all who have dyslexia There have been several special education approaches to help students with dyslexia. Adaptive technology, such as specialized computer software, has resulted in recent innovations helpful to many people with dyslexia. In this field there are several alternate therapies that are suggested for dyslexics. One factor that characterizes the field of dyslexia remediation is the stream of alternative therapies for developmental and learning disabilities.
These controversial treatments include nutritional supplements, special diets, homeopathy, and osteopathy/chiropractic manipulation. (Bull, 2008) | Most teaching is geared to remediating specific areas of weakness, such as addressing difficulties with phonetic decoding by providing phonics-based tutoring. Some teaching is geared to specific reading skill areas, such as phonetic decoding; whereas other approaches are more comprehensive in scope, combining techniques to address basic skills along with strategies to improve comprehension and literary appreciation.
Many programs are multisensory in design, meaning that instruction includes visual, auditory, and kinesthetic or tactile elements; as it is generally believed that such forms of instruction are more effective for dyslexic learners. Despite claims of some programs to be “research based”, there is very little empirical or quantitative research supporting the use of any particular approach to reading instruction as compared to another when used with dyslexic children (Connor et al. 2007). Torgesen (2004) emphasized the importance of explicit instruction for remediation as well as the need for intensity that is completely different from regular classroom instruction. To make gains in reading, students need highly structured, sequential interactive activities and close monitoring, directly connecting the known with the new, with sufficient time for practice of new skills to build automaticity. . Dyslexia interventions
Some teaching is geared to specific reading skill areas, such as phonetic decoding; whereas other approaches are more comprehensive in scope, combining techniques to address basic skills along with strategies to improve comprehension and literary appreciation. Many programs are multisensory in design, meaning that instruction includes visual, auditory, and kinesthetic or tactile elements; as it is generally believed that such forms of instruction are more effective for dyslexic learners (Henry, 1998). |
In 2007 the researchers Joseph Torgesen and Richard Wagner have shown that, when teaching children with reading disabilities, programs including systematic and explicit instruction in phoneme awareness and grapheme-phoneme correspondence are far more successful than programs that do not(Wolf,2007). Academic remediations With appropriate instruction, dyslexics can become skilled readers. Appropriate remedial instruction includes using: * Direct, explicit and comprehensive instruction in the structure of language * A systematic sequence for teaching individual skills Structured information from the simple to the complex * Simultaneous multisensory approaches, including combinations of visual, auditory, and kinesthetic modalities * Interaction between student and teacher during instruction of new skills * Reinforcement throughout the day of newly learned skills * Integrated spelling and handwriting instruction sequence with reading instruction, so that they are mutually reinforcing * Extended practice for each skill until the student overlearns the skill * Ongoing review of previously learned skills * Careful pacing to avoid information overload Intensive instruction until reading, spelling and writing skills are at grade level. * Repeated reading to help develop fluency and reading rate * Paired reading to help develop fluency and enhance comprehension (Heward, 2003). Classroom accommodations Although there are no treatments or quick cures for dyslexia there are many techniques that can be used to assist dyslexic students in the classroom while reading skills are being remediated. These include such things as: * Oral testing * Untimed tests * Eliminate or reduce spelling tests * Minimizing the need to read out loud * Accept dictated homework Reduce homework load * Grade on content, not spelling nor handwriting * Reduce copying tasks * Avoid or reduce essay tests * Providing teacher handouts to supplement the notes taken * Using materials that are not visually overcrowded * To increase motivation, giving assignments in areas in which the student has a strong interest, for example, sports stories, biographies of inventors or rock musicians, or fiction about teenage issues. * Using appropriate font type and size. It is suggested that Sassoon and Comic Sans may be the easiest to read; Times New Roman may be one of the most difficult to read.
The font should not be too small. There are several fonts and typefaces designed for dyslexia including Gill Dyslexic, Read Regular, Lexia Readable, Sylexiad, OpenDyslexic, and Dyslexie. (Alphabet writing systems only)(wikipedia. org). Recent developments Context & phonetic spell checkers and grammar checkers combined with text-to-speech and other assistive technologies aimed for help with dyslexia, such as Ghotit Dyslexia software, aim to make writing easier (speedchange. blogspot. com). Individuals with dyslexia require more practice to master skills in their areas of deficit.
In the circumstances where typically developing children need 30 to 60 hours training, the number of hours that has resulted in optimistic conclusions concerning the remediation of dyslexia is between 80 and 100 hours, or less if the intervention is started sufficiently early. Only approximately 20% of adults with early reading difficulties have acquired fluent reading skills in adulthood (Lyytinen et. al, 2007). Functional MRI (fMRI) studies have shown neurological changes in dyslexic children and adults who have used phonological interventions, with improved performance on tests of phonemic awareness and text decoding.
MRI studies have also shown changes in the brain and spelling improvement of dyslexic children taught spelling phonetically in an orthographic manner (Dahms, 2006). A recent study has shown that the usage of a FM system drives neural plasticity in children with dyslexia. A FM system is a personal assistive listening device, consisting of a wireless microphone worn by the teacher, and a wireless receiver similar to a Bluetooth receiver worn on the ears by the pupil.
Measurements of the brain’s response to speech sounds showed that the children who wore the device for one year responded more consistently to the very soft and rapidly changing elements of sounds that help distinguish one consonant from another (cat, bat, pat etc. ). That improved stability was linked with reading improvement based on standardized measures of readability – which, as a long-term benefit, points to brain plasticity (Hornickel, Zecker, Bradow & Kraus, 2012). 1. Bottom of Form REFERENCES 21 What Is Dyslexia? Education Research Foundation. Retrieved May, 2013 48 Henry, M K. 2005). The history and structure of the English language. Multisensory Teaching of Basic Language Skills. Baltimore, Maryland: Paul H. Brookes Publishing. 16 Chung KK, Ho CS, Chan DW, Tsang SM, Lee SH (2010). Cognitive profiles of Chinese adolescents with dyslexia. Dyslexia 16 (1): 2–23 54 Nicolson RI, Fawcett AJ (2009). Dyslexia, dysgraphia, procedural learning and the cerebellum. Cortex 47 (1): 117–27. 79 Cao F, Bitan T, Chou TL, Burman DD, Booth JR ( 2006). Deficient orthographic and phonological representations in children with dyslexia revealed by brain activation pattern.
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