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Dyslexia is a disorder characterized by problems with the visual notation of speech, which in most languages of European origin are problems with alphabet writing systems which have a phonetic construction. [1] Examples of these issues can be problems speaking in full sentences, problems correctly articulating Rs and Ls as well as Ms and Ns, mixing up sounds in multi-syllabic words (ex: aminal for animal, spahgetti for spaghetti, heilcopter for helicopter, hangaberg for hamburger, ageen for magazine, etc.), problems of immature speech such as "wed and gween" instead of "red and green".
The characteristics of dyslexia have been identified mainly from research in languages with alphabetic writing systems, primarily English. However, many of these characteristic may be transferable to other types of writing systems.
The causes of dyslexia are not agreed upon, although the consensus of neuroscientists believe dyslexia is a phonological processing disorder and that dyslexics have reading difficulties because they are unable to see or hear a word, break it down to discrete sounds, and then associate each sound with letters that make up the word. Some researchers believe that a subset of dyslexics have visual deficits in addition to deficits in phoneme processing, but this view is not universally accepted. In any case, there is no evidence that dyslexics literally "see" letters backward or in reverse order within words. Dyslexia is a language disorder, not a vision disorder.
Poor working memory may be another reason why those with dyslexia have difficulties remembering new vocabulary words. Remembering verbal instructions may also be a struggle. Dyslexics who have not been given structured language instruction may grow to depend on learning individual words by memory rather than decoding words by mapping phonemes (speech sounds) to graphemes (letters and letter combinations which represent individual speech sounds). [2]
Some shared symptoms of the speech or hearing deficits and dyslexia: [3]
The identification of these factors results from the study of patterns across many clinical observations of dyslexic children. In the UK, Thomas Richard Miles was important in such work, and his observations led him to develop the Bangor Dyslexia Diagnostic Test. [4]
In terms of reading and spelling, it is found that common characteristics include: [5] [ additional citation(s) needed ]
Because of literacy problems, an individual with dyslexia may have difficulty with handwriting. This can involve slower writing speed than average, poor handwriting characterized by irregularly formed letters, or inability to write straight on a blank paper with no guideline.
Some studies have also reported gross motor difficulties in dyslexia, including motor skills disorder. This difficulty is indicated by clumsiness and poor coordination. The relationship between motor skills and reading difficulties is poorly understood, but could be linked to the role of the cerebellum and inner ear in the development of reading and motor abilities. [6]
Dyslexia and dyscalculia are two learning disorders with different cognitive profiles. Dyslexia and dyscalculia have separable cognitive profiles, mainly a phonological deficit in the case of dyslexia and a deficient number module in the case of dyscalculia. [7]
Individuals with dyslexia can be gifted in mathematics while having poor reading skills. They might have difficulty with word processing problems (e.g. descriptive mathematics, engineering or physics problems that rely on written text rather than numbers or formulas).
A study has found that entrepreneurs are five times more likely to be dyslexic than average citizens. [8] [ better source needed ]
In the United States, researchers estimate the prevalence of dyslexia to range from three to ten percent of school-aged children, though some have put the figure as high as 17 percent. [9] [10] Recent studies indicate that dyslexia is particularly prevalent among small business owners, with roughly 20 to 35 percent of US and British entrepreneurs being affected. [11]
Evidence based on randomly selected populations of children indicate that dyslexia affects boys and girls equally; that dyslexia is diagnosed more frequently in boys appears to be the result of sampling bias in school-identified sample populations. [12]
Dyslexia, previously known as word blindness, is a learning disability that affects either reading or writing. Different people are affected to different degrees. Problems may include difficulties in spelling words, reading quickly, writing words, "sounding out" words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. The difficulties are involuntary, and people with this disorder have a normal desire to learn. People with dyslexia have higher rates of attention deficit hyperactivity disorder (ADHD), developmental language disorders, and difficulties with numbers.
In neuroscience and psychology, the term language center refers collectively to the areas of the brain which serve a particular function for speech processing and production. Language is a core system that gives humans the capacity to solve difficult problems and provides them with a unique type of social interaction. Language allows individuals to attribute symbols to specific concepts, and utilize them through sentences and phrases that follow proper grammatical rules. Finally, speech is the mechanism by which language is orally expressed.
Hyperlexia is a syndrome characterized by a child's precocious ability to read. It was initially identified by Norman E. Silberberg and Margaret C. Silberberg (1967), who defined it as the precocious ability to read words without prior training in learning to read, typically before the age of five. They indicated that children with hyperlexia have a significantly higher word-decoding ability than their reading comprehension levels. Children with hyperlexia also present with an intense fascination for written material at a very early age.
Dyscalculia is a disability resulting in difficulty learning or comprehending arithmetic, such as difficulty in understanding numbers, learning how to manipulate numbers, performing mathematical calculations, and learning facts in mathematics. It is sometimes colloquially referred to as "math dyslexia", though this analogy is misleading as they are distinct syndromes.
Dysgraphia is a neurological disorder and learning disability that concerns impairments in written expression, which affects the ability to write, primarily handwriting, but also coherence. It is a specific learning disability (SLD) as well as a transcription disability, meaning that it is a writing disorder associated with impaired handwriting, orthographic coding and finger sequencing. It often overlaps with other learning disabilities and neurodevelopmental disorders such as speech impairment, attention deficit hyperactivity disorder (ADHD) or developmental coordination disorder (DCD).
Reading for special needs has become an area of interest as the understanding of reading has improved. Teaching children with special needs how to read was not historically pursued due to perspectives of a Reading Readiness model. This model assumes that a reader must learn to read in a hierarchical manner such that one skill must be mastered before learning the next skill. This approach often led to teaching sub-skills of reading in a decontextualized manner. This style of teaching made it difficult for children to master these early skills, and as a result, did not advance to more advanced literacy instruction and often continued to receive age-inappropriate instruction.
A reading disability is a condition in which a person displays difficulty reading. Examples of reading disabilities include: developmental dyslexia, And alexia,
Donald P. ShankweilerArchived 2006-06-26 at the Wayback Machine is an eminent psychologist and cognitive scientist who has done pioneering work on the representation and processing of language in the brain. He is a Professor Emeritus of Psychology at the University of Connecticut, a Senior Scientist at Haskins Laboratories in New Haven, Connecticut, and a member of the Board of Directors Archived 2021-01-26 at the Wayback Machine at Haskins. He is married to well-known American philosopher of biology, psychology, and language Ruth Millikan.
The phonological deficit hypothesis is a prevalent cognitive-level explanation for the cause of reading difficulties and dyslexia. It stems from evidence that individuals with dyslexia tend to do poorly on tests which measure their ability to decode nonsense words using conventional phonetic rules, and that there is a high correlation between difficulties in connecting the sounds of language to letters and reading delays or failure in children.
Management of dyslexia depends on a multitude of variables; there is no one specific strategy or set of strategies that will work for all who have dyslexia.
Deep dyslexia is a form of dyslexia that disrupts reading processes. Deep dyslexia may occur as a result of a head injury, stroke, disease, or operation. This injury results in the occurrence of semantic errors during reading and the impairment of nonword reading.
Language-based learning disabilities or LBLD are "heterogeneous" neurological differences that can affect skills such as listening, reasoning, speaking, reading, writing, and math calculations. It is also associated with movement, coordination, and direct attention. LBLD is not usually identified until the child reaches school age. Most people with this disability find it hard to communicate, to express ideas efficiently and what they say may be ambiguous and hard to understand It is a neurological difference. It is often hereditary, and is frequently associated to specific language problems.
The history of dyslexia research spans from the late 1800s to the present.
Dyslexia is a reading disorder wherein an individual experiences trouble with reading. Individuals with dyslexia have normal levels of intelligence but can exhibit difficulties with spelling, reading fluency, pronunciation, "sounding out" words, writing out words, and reading comprehension. The neurological nature and underlying causes of dyslexia are an active area of research. However, some experts believe that the distinction of dyslexia as a separate reading disorder and therefore recognized disability is a topic of some controversy.
Dyslexia is a complex, lifelong disorder involving difficulty in learning to read or interpret words, letters and other symbols. Dyslexia does not affect general intelligence, but is often co-diagnosed with ADHD. There are at least three sub-types of dyslexia that have been recognized by researchers: orthographic, or surface dyslexia, phonological dyslexia and mixed dyslexia where individuals exhibit symptoms of both orthographic and phonological dyslexia. Studies have shown that dyslexia is genetic and can be passed down through families, but it is important to note that, although a genetic disorder, there is no specific locus in the brain for reading and writing. The human brain does have language centers, but written language is a cultural artifact, and a very complex one requiring brain regions designed to recognize and interpret written symbols as representations of language in rapid synchronization. The complexity of the system and the lack of genetic predisposition for it is one possible explanation for the difficulty in acquiring and understanding written language.
Rapid automatized naming (RAN) is a task that measures how quickly individuals can name aloud objects, pictures, colors, or symbols. Variations in rapid automatized naming time in children provide a strong predictor of their later ability to read, and is independent from other predictors such as phonological awareness, verbal IQ, and existing reading skills. Importantly, rapid automatized naming of pictures and letters can predict later reading abilities for pre-literate children.
Educational neuroscience is an emerging scientific field that brings together researchers in cognitive neuroscience, developmental cognitive neuroscience, educational psychology, educational technology, education theory and other related disciplines to explore the interactions between biological processes and education. Researchers in educational neuroscience investigate the neural mechanisms of reading, numerical cognition, attention and their attendant difficulties including dyslexia, dyscalculia and ADHD as they relate to education. Researchers in this area may link basic findings in cognitive neuroscience with educational technology to help in curriculum implementation for mathematics education and reading education. The aim of educational neuroscience is to generate basic and applied research that will provide a new transdisciplinary account of learning and teaching, which is capable of informing education. A major goal of educational neuroscience is to bridge the gap between the two fields through a direct dialogue between researchers and educators, avoiding the "middlemen of the brain-based learning industry". These middlemen have a vested commercial interest in the selling of "neuromyths" and their supposed remedies.
Phonological dyslexia is a reading disability that is a form of alexia, resulting from brain injury, stroke, or progressive illness and that affects previously acquired reading abilities. The major distinguishing symptom of acquired phonological dyslexia is that a selective impairment of the ability to read pronounceable non-words occurs although the ability to read familiar words is not affected. It has also been found that the ability to read non-words can be improved if the non-words belong to a family of pseudohomophones.
Dr Hollis Scarborough is an American psychologist and literacy expert who is a senior scientist at Haskins Laboratories in New Haven, Connecticut. She has been a leading researcher in the area of reading acquisition since 1981, and has been involved with efforts to improve US national policy on the teaching of reading.
The dual-route theory of reading aloud was first described in the early 1970s. This theory suggests that two separate mental mechanisms, or cognitive routes, are involved in reading aloud, with output of both mechanisms contributing to the pronunciation of a written stimulus.
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