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Encyclopedia > Dyslexia
Part of a series on
Dyslexia

and related disorders
Education · Neuropsychology Image File history File links No higher resolution available. ... Clinical neuropsychology is a subdiscipline of psychology that specialises in the clinical assessment and treatment of patients with brain injury or neurocognitive deficits. ...

RELATED CONDITIONS

Alexia
Auditory Processing Disorder
Dyscalculia · Dysgraphia
Dyslexia · Dyspraxia
Alexia (from the Greek , privative, expressing negation, and = word) is an acquired type of sensory aphasia where damage to the brain causes a patient to lose the ability to read. ... Auditory Processing Disorder (APD) (previously known as Central Auditory Processing Disorder (CAPD) is a disorder in how auditory information is processed in the brain. ... Dyscalculia (difficulty in learning or comprehending mathematics) was originally identified in case studies of patients who suffered specific arithmetic disabilities as a result of damage to specific regions of the brain. ... Dysgraphia (or agraphia) is a deficiency in the ability to write, regardless of the ability to read, not due to intellectual impairment. ... Developmental Dyspraxia is one or all of a heterogeneous range of psychological development disorders affecting the initiation, organization and performance of action[1]. It entails the partial loss of the ability to coordinate and perform certain purposeful movements and gestures in the absence of motor or sensory impairments. ...

THEORIES

Double deficit · Magnocellular
Perceptual noise exclusion
Phonological deficit
The ability to read is believed to depend on two skills. ... This article needs cleanup. ... The concept of a perceptual noise exclusion deficit is an emerging hypothesis as to the origins and nature of dyslexia. ... The phonological deficit hypothesis is a prevalent neurological explanation for the cause of reading difficulties and dyslexia. ...

RELATED TOPICS

IDEA · Literacy
Reading acquisition · Spelling
Recording for the Blind & Dyslexic
// The Individuals with Disabilities Education Act (IDEA) is a United States federal law that governs how states and public agences provide early intervention, special education, and related services to children with disabilities. ... Children reading. ... It has been suggested that this article or section be merged with Developmental Stages of Reading. ... Proper spelling is the writing of a word or words with all necessary letters and diacritics present in an accepted standard order. ... Recording for the Blind & Dyslexic (RFB&D) is a non-profit nationwide volunteer organization. ...

LISTS

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People · Publications
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The following is a list of notable people who have been diagnosed with dyslexia. ... Note: This page is intended as a list to provide a system of categorization and links to articles on the topics which are the subject of the lists, as part of the Dyslexia series. ...

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Dyslexia is a learning disability that manifests primarily as a difficulty with written language, particularly with reading and spelling. It is separate and distinct from reading difficulties resulting from other causes, such as a non-neurological deficiency with vision or hearing, or from poor or inadequate reading instruction.[1] Evidence suggests that dyslexia results from differences in how the brain processes written and/or spoken language. Although dyslexia is the result of a neurological difference, it is not an intellectual disability. Dyslexia occurs at all levels of intelligence; sub-average, average, above average, and highly gifted.[2] Alexia (from the Greek , privative, expressing negation, and = word) is an acquired type of sensory aphasia where damage to the brain causes a patient to lose the ability to read. ... Disabled redirects here. ... This article is about the learning activity. ... Proper spelling is the writing of a word or words with all necessary letters and diacritics present in an accepted standard order. ...


A University of Hong Kong study argues that dyslexia affects different structural parts of children's brains depending on the language which the children read.[3] The study focused on comparing children that were raised reading English and children raised reading Chinese. Using MRI technology researchers found that the children reading English used a different part of the brain than those reading Chinese. Researchers were surprised by this discovery and hope that the findings will help lead them to any neurobiological cause for dyslexia.[3] The mri are a fictional alien species in the Faded Sun Trilogy of C.J. Cherryh. ...


The word dyslexia comes from the Greek words δυσ- dys- ("impaired") and λέξις lexis ("word"). People with dyslexia are called dyslexic or dyslectic.

Contents

Overview

Dyslexia
Classification and external resources
ICD-10 F81.0, R48.0
ICD-9 315.02, 784.61
OMIM 127700 604254 606896 606616 608995 300509
DiseasesDB 4016
MeSH D004410

Dyslexia is most commonly characterized by difficulties with learning how to decode at the word level, to spell, and to read accurately and fluently. Dyslexia also makes mathematics more difficult as people with dyslexia might mix numbers up. Dyslexic individuals often have difficulty "breaking the code" of sound-letter association (the alphabetic principle), and they may also reverse or transpose letters when writing or confuse letters such as b, d, p, q, especially in childhood. However, dyslexia is not a visual problem that involves reading letters or words backwards or upside down, nor are such reversals a defining characteristic of dyslexia. The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) is a coding of diseases and signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or diseases, as classified by the World Health Organization (WHO). ... // F00-F99 - Mental and behavioural disorders (F00-F09) Organic, including symptomatic, mental disorders (F00) Dementia in Alzheimers disease (F01) Vascular dementia (F011) Multi-infarct dementia (F02) Dementia in other diseases classified elsewhere (F020) Dementia in Picks disease (F021) Dementia in Creutzfeldt-Jakob disease (F022) Dementia in Huntingtons... // R00-R99 - Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R09) Symptoms and signs involving the circulatory and respiratory systems (R00) Abnormalities of heart beat (R000) Tachycardia, unspecified (R001) Bradycardia, unspecified (R002) Palpitations (R008) Other and unspecified abnormalities of heart beat (R01) Cardiac murmurs and other... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ...


Many individuals with dyslexic symptoms involving reading, writing, and spelling also exhibit symptoms in other domains such as poor short-term memory skills, poor personal organizational skills and problems processing spoken language. [4] These symptoms may coexist with or overlap with characteristics among others of attention-deficit hyperactivity disorder, auditory processing disorder, [5] developmental dyspraxia, dyscalculia, and/or dysgraphia. However, dyslexia and attention deficit/hyperactivity disorder are not correlated developmental problems.[6] Short-term memory, sometimes referred to as primary, working, or active memory, is said to hold a small amount of information for about 20 seconds. ... Attention-Deficit Hyperactivity Disorder (ADHD), is a neurobehavioural developmental disorder[1] [2] [3] affecting about 3-5% of the worlds population under the age of 19[4]. It typically presents itself during childhood, and is characterized by a persistent pattern of inattention and/or hyperactivity, as well as forgetfulness... Auditory Processing Disorder (APD) (previously known as Central Auditory Processing Disorder (CAPD) is a disorder in how auditory information is processed in the brain. ... Developmental Dyspraxia is one or all of a heterogeneous range of psychological development disorders affecting the initiation, organization and performance of action[1]. It entails the partial loss of the ability to coordinate and perform certain purposeful movements and gestures in the absence of motor or sensory impairments. ... Dyscalculia (difficulty in learning or comprehending mathematics) was originally identified in case studies of patients who suffered specific arithmetic disabilities as a result of damage to specific regions of the brain. ... Dysgraphia (or agraphia) is a deficiency in the ability to write, regardless of the ability to read, not due to intellectual impairment. ...


Evidence that dyslexia is of neurological origin is substantial. Acquired dyslexias occur due to brain damage in the left hemisphere's key language areas, which may be a clue when it comes to developmental types. Research also suggests an association with biochemical and genetic markers.[7][8][9] However, experts disagree over the precise definition and criteria for diagnosis, and some advocate that the term dyslexia be dropped altogether and replaced with the term reading disorder or reading disability (RD). Because reading skills occur on a continuum with no clear distinction between typical readers and dyslexic readers, some experts assert that the term dyslexia should be reserved for the two to five percent with the most severe reading deficits. [10] Neurology is a branch of medicine dealing with disorders of the central and peripheral nervous systems. ... Wöhler observes the synthesis of urea. ... This article is about the general scientific term. ...


Dyslexia is a lifelong condition of which there is no way to reverse, but appropriate remedial instruction and compensatory strategies can help dyslexic individuals mitigate or overcome their difficulties with written language. [11] A large body of evidence shows which types of instruction dyslexics need to be successful. [12] Many dyslexics overcome early problems with literacy and go on to earn advanced degrees and pursue successful careers; a high level of motivation coupled with strong encouragement and mentorship have been identified as factors leading to their success. [13]


History

Identified for the first time by Oswald Berkhan in 1881, [14] the term 'dyslexia' was coined in 1887 by Rudolf Berlin, an ophthalmologist practicing in Stuttgart, Germany.[15] He used the term to refer to a case of a young boy who had a severe impairment in learning to read and write in spite of showing typical intellectual and physical abilities in all other respects. Ophthalmology is the branch of medicine which deals with the diseases of the eye and their treatment. ... For other uses, see Stuttgart (disambiguation). ...


In 1896, W. Pringle Morgan, a British physician, from Seaford, East Sussex, England published a description of a reading-specific learning disorder in a report to the British Medical Journal titled "Congenital Word Blindness". This described the case of a 14-year-old boy who had not yet learned to read, yet showed normal intelligence and was generally adept at other activities typical of children of that age.[16] , Seaford is a coastal town in the county of East Sussex, England, on the south coast, east of Newhaven, Brighton and west of Eastbourne. ... For other uses, see England (disambiguation). ...


During the 1890s and early 1900s, James Hinshelwood, a British ophthalmologist, published a series of articles in medical journals describing similar cases of congenital word blindness, which he defined as "a congenital defect occurring in children with otherwise normal and undamaged brains characterised by a difficulty in learning to read." In his 1917 book Congenital Word Blindness, Hinshelwood asserted that the primary disability was in visual memory for words and letters, and described symptoms including letter reversals, and difficulties with spelling and reading comprehension.[17]


A key early researcher in dyslexia was Samuel T. Orton, a neurologist who worked primarily with stroke victims. In 1925 Orton met a boy who could not read and who exhibited symptoms similar to stroke victims who had lost the ability to read. Orton began studying reading difficulties and determined that there was a syndrome unrelated to brain damage that made learning to read difficult. Orton called the condition strephosymbolia (meaning 'twisted signs') to describe his theory that individuals with dyslexia had difficulty associating the visual forms of words with their spoken forms.[18] Orton observed that reading deficits in dyslexia did not seem to stem from strictly visual deficits.[19] He believed the condition was caused by the failure to establish hemispheric dominance in the brain.[20] He also observed that the children he worked with were disproportionately left- or mixed-handed, although this finding has been difficult to replicate.[21] Orton's hypothesis concerning hemispheric specialization was borne out by post-mortem studies in the 1980s and 1990s establishing that the left planum temporale, a brain area associated with language processing, is physically larger than the corresponding right area in the brains of non-dyslexic subjects, but that these brain areas are symmetrical or slightly larger on the right for dyslexic subjects.[22] FMRI imaging studies of children and young adults reported in 2003 provide further support, demonstrating that increases in age and reading level are associated with a suppression of right hemispheric activity.[23] [24] Samuel Torrey Orton (October 15, 1879–November 17, 1948) was an American physician who pioneered the study of learning disabilities. ... The human brain is separated by a longitudinal fissure, separating the brain into two distinct cerebral hemispheres by the corpus callosum. ... The planum temporale is the posterior superior surface of the superior temporal gyrus in the cerebrum. ... Functional Magnetic Resonance Imaging (or fMRI) describes the use of MRI to measure hemodynamic signals related to neural activity in the brain or spinal cord of humans or other animals. ...


Influenced by the kinesthetic work of Helen Keller and Grace Fernald, and looking for a way to teach reading using both left and right brain functions,[25] Orton later worked with psychologist and educator Anna Gillingham to develop an educational intervention that pioneered the use of simultaneous multisensory instruction. The Orton-Gillingham approach to remedial reading instruction is still widely used and forms the basis of many reading intervention programs. [26] Helen Adams Keller (June 27, 1880 – June 1, 1968) was an American author, activist and lecturer. ... The Orton-Gillingham approach to reading instruction was developed in the early twentieth century. ...


In contrast, Dearborn, Gates, Bennet and Blau considered a faulty guidance of the seeing mechanism to be the cause. The data collected in 1931 by Tinker and Goodenough (The J.Educ. Psych.) seemed to support this thesis. They wanted to know if a conflict between spontaneous orientation of the scanning action of the eyes from right to left and training aimed at the acquisition of an opposite direction would allow an interpretation of the facts observed in the dyslexic disorder and especially of the ability to mirror-read. To this end the authors asked four adults to read a text reflected in a mirror for ten minutes a day for a period of five months. It was confirmed that in all the subjects, the words were not perceived in their globality but required a meticulous analysis of the letters and syllables.


Moreover they also demonstrated either total or partial inversions even sometimes affecting the order of the words in a sentence. What is more, they revealed a curious impression of not just horizontal but also vertical inversions.These are errors that exist amongst dyslexics and they suffer from the aggravating circumstance inherent in all learning. What remained to be demonstrated was that there exists a preference amongst dyslexics, without sensory deficiency, or mental retardation, or any backwardness in speech or language, towards scanning with the eyes from right to left. Proof of this was provided in a work conducted under Clement Launay in 1949 (thesis G. Mahec Paris 1951). In adult subjects the reading of a series of 66 tiny lower-case letters, 5mm high, spaced 5mm apart, first from left to right and then from right to left was more easily and quickly done in the left to right direction. For former dyslexic children, a substantial number read a series of 42 letters with equal speed in both directions and some (10%) read better from right to left than from left to right. The phenomenon is clearly linked to the dynamics of sight as it disappears when the space between letters is increased, transforming the reading into spelling. This experience also explains the ability to mirror-read. This reading test can also be used to diagnose serious cases of dyslexia.


In the 1970s, a new hypothesis, based in part on Orton's theories, emerged that dyslexia stems from a deficit in phonological processing or difficulty in recognizing that spoken words are formed by discrete phonemes (for example, that the word CAT comes from the sounds [k], [æ], and [t]). As a result, affected individuals have difficulty associating these sounds with the visual letters that make up written words. Key studies of the phonological deficit hypothesis include the finding that the strongest predictor of reading success in school age children is phonological awareness,[27] and that phonological awareness instruction can improve decoding skills for children with reading difficulties.[28] Phonology (Greek phonÄ“ = voice/sound and logos = word/speech), is a subfield of linguistics which studies the sound system of a specific language (or languages). ... In human language, a phoneme is the theoretical representation of a sound. ... The phonological deficit hypothesis is a prevalent neurological explanation for the cause of reading difficulties and dyslexia. ... Phononological awareness is often confused with phonics but it is really a precursor to phonics. ...


The advent of neuroimaging techniques to study brain structure and function enhanced the research in the 1980s and 1990s. Since then, interest in the neurologically based causes has persisted. Current models of the relation between the brain and dyslexia generally focus on some form of defective or delayed brain maturation. More recently, genetic research has provided increasing evidence supporting a genetic origin of dyslexia [29]. It has been suggested that this article or section be merged with functional neuroimaging. ... This article is about the general scientific term. ...


Researchers are currently searching for a link between the neurological and genetic findings, and the reading disorder. There are many previous and current theories of dyslexia, but the one that has the most support from research is that, whatever the biological cause, dyslexia is a matter of reduced phonogical awareness, the ability to analyze and link the units of spoken and written languages. [30].


Subtypes of developmental dyslexia

Castles and Coltheart prove through their study that developmental dyslexia includes at least two prevalent and distinct varieties or subtypes of dyslexia. Subtypes include surface dyslexia and phonological dyslexia. Understanding these subtypes is useful in diagnosing learning patterns and developing approaches for overcoming impairments that may be visual perception impairments or speech discrimination deficits. These subtypes are based on differing patterns of underlying symptoms, as supported by a finding using large-scale data from comparative studies of reading patterns in dyslexic and normal readers [31]. In the study by Castles and Coltheart, 56 dyslexic boys and 56 non-dyslexic boys as a control group were tested. During the test, the boys read aloud words and non words that were presented to them. The researchers found that surface dyslexics (subjects who have poor lexical skills, or can’t make out irregular words well) had a mean difference of 14.4 words between reading regular words versus irregular words, however, the mean difference in subjects with phonological dyslexia (subjects who can’t use sub lexical skills, or can’t make out non words) was only 7.75 words which was comparable to the control group [31].Surface dyslexia is the outcome of an individual who cannot function using the lexical procedure for reading out loud. The lexical procedure includes sounding out a word though the use of a past word already known [31].


Phonological dyslexia


Phonological dyslexia is characterized by subjects who can read aloud both regular and irregular words but have difficulties with non words and with connecting sounds to symbols, or with sounding out words [31]. Phonological processing tasks predict reading accuracy and comprehension. This subtype is the most predominant form of dyslexia [32] Castles, A., & Coltheart, M. (1993). Varieties of developmental dyslexia. Cognition, 47(2), 149-180 </ref>.In Castles and Coltheart’s study, they had 56 dyslexic boys and 56 non dyslexic boys read words and non words given to them. The majority of the boys, 55%, showed a phonological dyslexic pattern [31].In Castles and Coltheart’s study, dyslexic subjects and control subjects were asked to read non words listed on a card, 17 out of 51 cases of dyslexics were below the confidence limit in non word reading, which was derived by the control group of subjects their own age. These phonological dyslexics have a lower non word reading level than expected by reviewing their irregular word reading level [33]. Phonological dyslexia is the outcome of a subject who cannot function using the sub lexical (pronunciations are constructed from smaller orthographic components) procedure for reading out loud [31]. In their study, Wolf and Bowers tested out naming speed by having their subjects name a symbol as quickly as possible when shown on a flash card. Difficulties in naming speed exist in conjunction with a phonological deficit, is characterized as double deficit dyslexia [34].


Variations and related conditions

Dyslexia is a learning disability. It has many underlying causes that are believed to be a brain-based condition that influences the ability to read written language. It is identified in individuals who fail to learn to read in the absence of a verbal or nonverbal intellectual impairment, sensory deficit (e.g., a visual deficit or hearing loss), pervasive developmental deficit or a frank neurological impairment.


The following conditions may also be contributory or overlapping factors, or underlying cause of the dyslexic symptoms as they can lead to difficulty reading:

  • Auditory processing disorder is a condition that affects the ability to encode auditory information. It can lead to problems with auditory working memory and auditory sequencing. Many dyslexics have auditory processing problems including history of auditory reversals. Auditory processing disorder is recognized as one of the major causes of dyslexia.
  • Cluttering is a speech fluency disorder involving both the rate and rhythm of speech, and resulting in impaired speech intelligibility. Speech is erratic and dysrhythmic, consisting of rapid and jerky spurts that usually involve faulty phrasing. The personality of the clutterer bears striking resemblance to the personalities of those with learning disabilities.[35]
  • Dyspraxia is a neurological condition characterized by a marked difficulty in carrying out routine tasks involving balance, fine-motor control, and kinesthetic coordination. Problems with short term memory and organization are typical of dyspraxics. This is most common in dyslexics who also have attention deficit disorder.
  • Verbal dyspraxia is a neurological condition characterized 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 is a disorder which expresses itself primarily during writing or typing, although in some cases it may also affect eye-hand coordination in such direction or sequence oriented processes as tying knots or carrying out a repetitive task. Dysgraphia is distinct from Dyspraxia in that the person may have the word to be written or the proper order of steps in mind clearly, but carries the sequence out in the wrong order.
  • Dyscalculia is a neurological condition characterized by a problem with learning fundamentals and one or more of the basic numerical skills. Often people with this condition can understand very complex mathematical concepts and principles but have difficulty processing formulas and even basic addition and subtraction.
  • Scotopic sensitivity syndrome, also known as Irlen Syndrome, is a term used to describe sensitivity to certain wavelengths of light which interfere with proper visual processing. See also Orthoscopics and asfedia.

Auditory Processing Disorder (APD) (previously known as Central Auditory Processing Disorder (CAPD) is a disorder in how auditory information is processed in the brain. ... Cluttering (also called tachyphemia) is a communicative disorder characterized by speech that is difficult for listeners to understand due to rapid speaking rate, erratic rhythm, poor syntax or grammar, and words or groups of words unrelated to the sentence. ... It has been suggested that this article or section be merged with Apraxia. ... DISCLAIMER Please remember that Wikipedia is offered for informational use only. ... Dyspraxia is a life-long developmental coordination disorder that is more common in males than in females, and has been believed to affect 8% to 10% of all children (Dyspraxia Trust, 1991). ... Dysgraphia (or agraphia) is a deficiency in the ability to write, regardless of the ability to read, not due to intellectual impairment. ... It has been suggested that this article or section be merged with Apraxia. ... Dyscalculia (difficulty in learning or comprehending mathematics) was originally identified in case studies of patients who suffered specific arithmetic disabilities as a result of damage to specific regions of the brain. ... Scotopic sensitivity syndrome, also known as Meares-Irlen syndrome or Irlen syndrome, is a broadly defined visual perceptual disorder affecting primarily reading and writing based activities. ... ... Orthoscopics is a treatment using computerized assessment and colored lenses to treat migraines and vision-related reading problems. ... Asfedia, formerly known as Irlens Syndrome and Scotopic Sensitivity (Syndrome), is a reading disability. ...

Scientific research

Theories of developmental dyslexia

The following theories should not be viewed as competing, but viewed as theories trying to explain the underlying causes of a similar set of symptoms from a variety of research perspectives and backgrounds.


The evolutionary hypothesis

This theory posits that reading is an unnatural act, and carried out by humans for an exceedingly brief period in our evolutionary history (Dalby, 1986). It has been less than a hundred years that most western societies promoted reading by the mass population and therefore the forces that shape our behavior have been weak. Many areas of the world still do not have access to reading for the majority of the population. There is no evidence that "pathology" underlies dyslexia but much evidence for cerebral variation or differences. It is these essential differences that are taxed with the artificial task of reading. [36]


The phonological hypothesis

The phonological hypothesis postulates that dyslexics have a specific impairment in the representation, storage and/or retrieval of speech sounds. It explains dyslexics' reading impairment on the basis that learning to read an alphabetic system requires learning the grapheme/phoneme correspondence, i.e. the correspondence between letters and constituent sounds of speech. If these sounds are poorly represented, stored or retrieved, the learning of grapheme/phoneme correspondences, the foundation of reading by phonic methods for alphabetic systems, will be affected accordingly.[37] The phonological deficit hypothesis is a prevalent neurological explanation for the cause of reading difficulties and dyslexia. ...


The rapid auditory processing theory

The rapid auditory processing theory is an alternative to the phonological deficit theory, which specifies that the primary deficit lies in the perception of short or rapidly varying sounds. Support for this theory arises from evidence that dyslexics show poor performance on a number of auditory tasks, including frequency discrimination and temporal order judgment. Backward masking tasks, in particular, demonstrate a 100-fold (40 dB) difference in sensitivity between normals and dyslexics. [38] Abnormal neurophysiological responses to various auditory stimuli have also been demonstrated. The failure to correctly represent short sounds and fast transitions would cause further difficulties in particular when such acoustic events are the cues to phonemic contrasts, as in /ba/ versus /da/. There is also evidence that dyslexics may have poorer categorical perception of certain contrasts.[37]


The visual theory

The visual theory (Lovegrove et al., 1980; Livingstone et al., 1991; Stein and Walsh, 1997) reflects another long standing tradition in the study of dyslexia, that of considering it as a visual impairment giving rise to difficulties with the processing of letters and words on a page of text. This may take the form of unstable binocular fixations, poor vergence, or increased visual crowding. The visual theory does not exclude a phonological deficit, but emphasizes a visual contribution to reading problems, at least in some dyslexic individuals. At the biological level, the proposed aetiology of the visual dysfunction is based on the division of the visual system into two distinct pathways that have different roles and properties: the magnocellular and parvocellular pathways. The theory postulates that the magnocellular pathway is selectively disrupted in certain dyslexic individuals, leading to deficiencies in visual processing, and, via the posterior parietal cortex, to abnormal binocular control and visuospatial attention. Evidence for magnocellular dysfunction comes from anatomical studies showing abnormalities of the magnocellular layers of the lateral geniculate nucleus (Livingstone et al., 1991), psychophysical studies showing decreased sensitivity in the magnocellular range, i.e. low spatial frequencies and high temporal frequencies in dyslexics, and brain imaging studies.[37] A vergence is the simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision ^ . The two eyes converge to point to the same object When a creature with binocular vision looks at an object, the eyes must rotate around a vertical axis so that the...


The cerebellar theory

Yet another view is represented by the automaticity/ cerebellar theory of dyslexia. Here the biological claim is that the dyslexic's cerebellum is mildly dysfunctional and that a number of cognitive difficulties ensue. First, the cerebellum plays a role in motor control and therefore in speech articulation. It is postulated that retarded or dysfunctional articulation would lead to deficient phonological representations. Secondly, the cerebellum plays a role in the automatization of overlearned tasks, such as driving, typing and reading. A weak capacity to automatize would affect, among other things, the learning of grapheme±phoneme correspondences. Support for the cerebellar theory comes from evidence of poor performance of dyslexics in a large number of motor tasks, in dual tasks demonstrating impaired automatization of balance, and in time estimation, a non-motor cerebellar task. Brain imaging studies have also shown anatomical, metabolic and activation differences in the cerebellum of dyslexics.[37]


The magnocellular theory

There is a unifying theory that attempts to integrate all the findings mentioned above. A generalization of the visual theory, the magnocellular theory postulates that the magnocellular dysfunction is not restricted to the visual pathways but is generalized to all modalities (visual and auditory as well as tactile). Furthermore, as the cerebellum receives massive input from various magnocellular systems in the brain, it is also predicted to be affected by the general magnocellular defect (Stein et al., 2001). Through a single biological cause, this theory therefore manages to account for all known manifestations of dyslexia: visual, auditory, tactile, motor and, consequently, phonological. Beyond the evidence pertaining to each of the theories described previously, evidence specifically relevant to the magnocellular theory includes magnocellular abnormalities in the medial as well as the lateral geniculate nucleus of dyslexics' brains, poor performance of dyslexics in the tactile domain, and the co-occurrence of visual and auditory problems in certain dyslexics.[37]


Perceptual visual-noise exclusion hypothesis

The concept of a perceptual noise exclusion (Visual-Noise) deficit is an emerging hypothesis, supported by research showing that dyslexic subjects experience difficulty in performing visual tasks such as motion detection in the presence of perceptual distractions, but do not show the same impairment when the distracting factors are removed in an experimental setting.[39] The researchers have analogized their findings concerning visual discrimination tasks to findings in other research related to auditory discrimination tasks. They assert that dyslexic symptoms arise because of an impaired ability to filter out both visual and auditory distractions, and to categorize information so as to distinguish the important sensory data from the irrelevant.[40] The concept of a perceptual noise exclusion deficit is an emerging hypothesis as to the origins and nature of dyslexia. ...


Research also indicates

Genetic factors

Studies have linked several forms of dyslexia to genetic markers.[41][42][43] One major genetic study identified a region on chromosome 6, DCDC2, as possibly linked to dyslexia.[8] This article is about the general scientific term. ... For information about chromosomes in genetic algorithms, see chromosome (genetic algorithm). ... DCDC2 is a gene that has been identified with the development of dyslexia. ...


As of 2007, genetic research in families with dyslexia have identified nine chromosome regions that may be associated with susceptibility to dyslexia. However, several of the major studies have not been replicated.[44]


Physiology

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.[45] [46] Functional magnetic resonance imaging (fMRI) is the use of MRI to measure the haemodynamic response related to neural activity in the brain or spinal cord of humans or other animals. ... Image of a typical positron emission tomography (PET) facility Positron emission tomography (PET) is a nuclear medicine medical imaging technique which produces a three-dimensional image or map of functional processes in the body. ... Inferior frontal gyrus of the human brain. ... The inferior parietal lobule (subparietal district or lobule) lies below the horizontal portion of the intraparietal sulcus, and behind the lower part of the postcentral sulcus. ... Categories: Stub | Cerebrum ...


Scientific studies of brains donated to medical research have revealed that there are anatomical differences in two parts of the dyslexic brain: the cerebral cortex and the thalamus. In 1979 Albert Galaburda of Harvard Medical School noticed anatomical differences in the language center in a dyslexic brain, showing microscopic differences known as ectopias and microgyria. Both affect the typical six-layer structure of the cortex. An ectopia is a collection of neurons that have pushed up from the lower layers of the cortex into the outermost one. A microgyrus is an area of cortex that includes only four layers instead of six. These differences affect connectivity and functionality of the cortex in critical areas related to auditory processing and visual processing, which seems consistent with the hypothesis that dyslexia stems from a phonological awareness deficit. Harvard Medical School (HMS) is one of the graduate schools of Harvard University. ... The language center is part of the human brain cortex where most of language processing takes place. ... Ectopia is a displacement or malposition of an organ of the body. ... A microgyrus is an area of the cerebral cortex that includes only four cortical layers instead of six. ... In neuroanatomy the cortex is the outermost layer of the brain. ... This article is about cells in the nervous system. ... Auditory Processing Disorder (APD) (previously known as Central Auditory Processing Disorder (CAPD) is a disorder in how auditory information is processed in the brain. ... Visual processing is the sequence of steps that information takes as it flows from visual sensors to cognitive processing. ...


Studies of both autopsied brains and living brains using neuroimaging techniques have shown that the brains of dyslexic children are symmetrical, unlike the asymmetrical brains of non-dyslexic readers who had larger left hemispheres.[47]


Scientists do not claim that all people with dyslexia have these structural brain differences. However, the studies are evidence that some children's reading problems are brain based. The challenge for researchers is to determine how these structural differences affect reading acquisition. [48]


Effect of language orthography

Some studies have concluded that speakers of languages whose orthography has a highly consistent correspondence between letter and sound (e.g., Italian) suffer less from the effects of dyslexia than speakers of languages where the letter-sound correspondence is less consistent (e.g. English and French).[49] The orthography of a language specifies the correct way of using a specific writing system to write the language. ... The English language is a West Germanic language that originates in England. ...


In one of these studies, reported in Seymour et al.,[50] the word-reading accuracy of first-grade children of different European languages was measured. English children had an accuracy of just 40%, whereas among children of most other European languages accuracy was about 95%, with French and Danish children somewhere in the middle at about 75%; Danish and French are known to have an irregular pronunciation.


However, this does not mean that dyslexia is caused by orthography: instead, Ziegler et al.[51] claim that the dyslexia suffered by German or Italian dyslexics is of the same kind as the one suffered by the English ones, supporting the theory that the origin of dyslexia is biological. In a study by Paulescu et al. (Science, 2001) English, French, and Italian dyslexics were found to have the same brain function signature when studied with functional magnetic resonance imaging (fMRI), a signature that differed from non-dyslexic readers. However, dyslexia has more pronounced effects on orthographically difficult languages, e.g., dyslexics have more difficulty in English than Italian. Modern theories of some forms of dyslexia uses orthography to test a hypothesis of psychological causation Functional Magnetic Resonance Imaging (or fMRI) describes the use of MRI to measure hemodynamic signals related to neural activity in the brain or spinal cord of humans or other animals. ...


Characteristics

Formal diagnosis of dyslexia is made by a qualified professional, such as a neurologist or an educational psychologist. Evaluation generally includes testing of reading ability together with measures of underlying skills such as tests of rapid naming, to evaluate short term memory and sequencing skills, and nonword reading to evaluate phonological coding skills. Evaluation will usually also include an IQ test to establish a profile of learning strengths and weaknesses. However, the use of a "discrepancy" between full scale IQ and reading level as a factor in diagnosis has been discredited by recent research.[52] It often includes interdisciplinary testing to exclude other possible causes for reading difficulties, such as a more generalized cognitive impairment or physical causes such as problems with vision or hearing.


Recent advances in neuroimaging and genetics provide evidence that could potentially help identify children with dyslexia before they learn to read in the future. However, such tests have not yet been developed and more research is needed before such testing could be considered reliable. It has been suggested that this article or section be merged with functional neuroimaging. ... This article is about the general scientific term. ...


Speech, hearing and listening

Speech delays may be an early warning sign of dyslexia. Many dyslexics may have problems processing and decoding auditory input prior to reproducing their own version of speech. Early stuttering or cluttering can also be warning signs of dyslexia. “Stutter” redirects here. ... Cluttering (also called tachyphemia) is a communicative disorder characterized by speech that is difficult for listeners to understand due to rapid speaking rate, erratic rhythm, poor syntax or grammar, and words or groups of words unrelated to the sentence. ...


Many dyslexics also can have problems with speaking clearly. They can mix up sounds in multi-syllabic words (ex: aminal for animal, bisghetti for spaghetti, hekalopter for helicopter, hangaberg for hamburger, mazageen for magazine, etc.) They also can have problems speaking in full sentences. They can have trouble correctly articulating Rs and Ls as well as Ms and Ns. They often have "immature" speech. They may still be saying "wed and gween" instead of "red and green" in second or third grade. Many dyslexics might have speech therapy in special education. They may have fast speech, cluttered speech, or hesitant speech. [53] [54] Cluttered speech is a common term for speech that becomes broken down, cluttered, or unintelligible due to a variety of reasons. ...


Reading requires the sounding out of words. Therefore, it makes sense that children with speech problems can end up having reading problems later. Many have problems with speech due to problems with auditory processing disorder issues. Auditory Processing Disorder (APD) (previously known as Central Auditory Processing Disorder (CAPD) is a disorder in how auditory information is processed in the brain. ...


Many dyslexics have problems with phonemic awareness. Phonemes are the smallest units in spoken language. The Auditory related underlying causes of dyslexia may be partially remediated by auditory therapy or speech therapy, which help with phonemic awareness. This may help to make sense of phonics which may help with phonological awareness, which is needed to sound out words.


Many acquire auditory processing disorder as an underlying cause of dyslexia from glue ear, otitis media. Auditory Processing Disorder (APD) (previously known as Central Auditory Processing Disorder (CAPD) is a disorder in how auditory information is processed in the brain. ... Otitis media is inflammation of the middle ear: the small space between the ear drum and the inner ear. ...


Some shared symptoms of the speech/hearing deficits and dyslexia:

  1. Confusion with before/after, right/left, and so on
  2. Difficulty learning the alphabet
  3. Difficulty with word retrieval or naming problems
  4. Difficulty identifying or generating rhyming words, or counting syllables in words (phonological awareness)
  5. Difficulty with hearing and manipulating sounds in words (phonemic awareness)
  6. Difficulty distinguishing different sounds in words (auditory discrimination)
  7. Difficulty in learning the sounds of letters
  8. Difficulty associating individual words with their correct meanings
  9. Difficulty with time keeping and concept of time
  10. Confusion with combinations of words
  11. Due to fear of speaking incorrectly, some children become withdrawn and shy or become bullies out of their inability to understand the social cues in their environment

Reading and spelling

  • Spelling errors — Because of difficulty learning letter-sound correspondences, individuals with dyslexia might tend to misspell words, or leave vowels out of words.
  • Letter order - Dyslexics may also reverse the order of two letters especially when the final, incorrect, word looks similar to the intended word (e.g., spelling "dose" instead of "does").
  • Highly phoneticized spelling - Dyslexics also commonly spell words inconsistently, but in a highly phonetic form such as writing "shud" for "should". Dyslexic individuals also typically have difficulty distinguishing among homophones such as "their" and "there".
  • Reading — Due to dyslexics' excellent long term memory, young students tend to memorize beginning readers, but are unable to read individual words or phrases.
  • Vocabulary - Having a small written vocabulary, even if they have a large spoken vocabulary.

This article is about the term in linguistics. ... Long-term memory (LTM) is memory that lasts from days to years. ...

Writing and motor skills

Because of literacy problems, an individual with dyslexia may have difficulty with handwriting. This can involve slower writing speed than average or poor handwriting characterised by irregularly formed letters. They may use inappropriate words when writing.


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.[55] Motor skills disorder (also known as motor coordination disorder or motor dyspraxia) is a human developmental disorder and is neurological in origin. ... The cerebellum (Latin: little brain) is a region of the brain that plays an important role in the integration of sensory perception and motor control. ...


Mathematical abilities

Dyslexia should not be confused with dyscalculia, a learning disability marked by severe difficulties with mathematics. Individuals with dyslexia can be gifted in mathematics while having poor reading skills. However, in spite of this they might have difficulty with word problems (i.e., descriptive mathematics, engineering, or physics problems that rely on written text rather than numbers or formulas). Individuals with dyslexia may also have difficulty remembering mathematical facts, such as multiplication tables, learning the sequence of steps when performing calculations, such as long division, and other mathematics which involve remembering the order in which numbers appear. This may be exhibited by having a slow response in mathematical drills and difficulty with word problems. Dyscalculia (difficulty in learning or comprehending mathematics) was originally identified in case studies of patients who suffered specific arithmetic disabilities as a result of damage to specific regions of the brain. ...


Creativity and arts

Dyslexics may be more creative than non-dyslexics. Such a superiority explains the high prevalence of dyslexics who succeed as entrepreneurs - entrepreneurs are five times more likely to suffer from dyslexia than an average citizen[56]. For instance, Ingvar Kamprad, one of the world's richest persons, is a dyslexic.   (born March 30, 1926) is a Swedish entrepreneur who is the founder of the home furnishing retail chain IKEA. As of 2007 he is the richest person in Europe and the 4th richest person in the world according to Forbes magazine, with an estimated net worth of around US$33...


Many successful artists are also dyslexics, e.g. actress Liv Tyler [57] Liv Tyler (born Liv Rundgren, on July 1, 1977, at Mount Sinai Hospital in New York City, New York[1]) is an American actress and model. ...


Remedial programs and technologies

There is no cure for dyslexia, but dyslexic individuals can learn to read and write with appropriate education or treatment. There is wide research evidence indicating that specialized phonics instruction can help remediate the reading deficits. The fundamental aim is to make children aware of correspondences between graphemes and phonemes, and to relate these to reading and spelling. It has been found that training, that is also focused towards visual language and orthographic issues, yields longer-lasting gains than mere oral phonological training.[30] For the study of sounds and speech sounds, see Acoustics and Phonetics. ... In typography, a grapheme is the atomic unit in written language. ... In human language, a phoneme is the theoretical representation of a sound. ... The orthography of a language specifies the correct way of using a specific writing system to write the language. ...


Effective training is given by teachers at school or kindergarten. Meta-analysis evaluating the effects of phonological awareness instruction has shown that word reading skills of all children, those with a risk for reading problems as well as those developing typically, improved their reading in systematic phonics instruction, a method that encourages a word to be recognised through the building of its constituent sounds. Basic phonemic awareness instruction did not, however, improve spelling in disabled readers.[58] None of the studies included measures of reading fluency.[59] Phononological awareness is often confused with phonics but it is really a precursor to phonics. ...


The core deficit of dyslexia is in learning to read at the word level [60], and 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 treatability 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. [30]


Functional MRI (fMRI) studies have shown changes in the brains of dyslexic children and adults with phonics tutoring, along with improved performance on tests of phonemic awareness and text decoding.[61] [62] Functional MRI studies have also shown changes in the brain and spelling improvement of dyslexic children taught spelling phonetically in an orthographic manner. [63] Functional Magnetic Resonance Imaging (or fMRI) describes the use of MRI to measure hemodynamic signals related to neural activity in the brain or spinal cord of humans or other animals. ... Functional Magnetic Resonance Imaging (or fMRI) describes the use of MRI to measure hemodynamic signals related to neural activity in the brain or spinal cord of humans or other animals. ... Proper spelling is the writing of a word or words with all necessary letters and diacritics present in an accepted standard order. ... The orthography of a language specifies the correct way of using a specific writing system to write the language. ...


One factor that characterises the field of dyslexia treatment is the incessant flow of alternative therapeutic approaches. These controversial treatments include sensory, dietary, and movement-based approaches as well as many others. [64]

See also: Dyslexia treatment and Alternative therapies for developmental and learning disabilities

// Alternative therapies for learning disabilities and developmental disabilities include a wide range of practices used in the treatment of dyslexia, ADHD, Asperger syndrome, autism and others. ...

Facts and statistics

In the United States, researchers estimate the prevalence of dyslexia to range from five to nine percent of school-aged children, though some have put the figure as high as 17 percent.[65][66] Recent studies indicate that dyslexia is particularly prevalent among small business owners, with roughly 20 to 35 percent of U. S. and British entrepreneurs being affected. Researchers consider that many dyslexic entrepreneurs are successful by delegating responsibilities and excelling at verbal communication.[67] Mom and pop store redirects here. ...


Dyslexia's main manifestation is a difficulty in developing word-level 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 developmental. Most scientific criteria for dyslexia exclude cases that can be explained as arising from environmental factors such as lack of education or total sensory deficits. Primary or elementary education is the first years of formal, structured education that occurs during childhood. ...


Dyslexia can be substantially compensated for with proper therapy, training, and assistive technology. Many coping strategies are developed subconsciously by the individual dyslexic.


Dyslexia has many variations dependent on the cultural choice of visual notation of speech. So the nature of the notation used in different cultures creates different types of problems for their groups of dyslexics. The differences between the English text and Chinese characters is a good example.


Legal and educational support issues

In the United States, Canada, New Zealand and in the United Kingdom, it has been claimed that there is a lack of adequate support and a general lack of interest in the learning disabilities of children in public schools.[citation needed] 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: English law is a formal term of art that describes the law for the time being in force in England and Wales. ... Her Majestys Court of Appeal is the second most senior court in the English legal system, with only the Judicial Committee of the House of Lords above it. ... 129. ...

"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, often without cost, for teachers and students.[68][69][70] It has been suggested that Knight Kadosh be merged into this article or section. ...


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 for 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. Fail and Phail redirect here. ... This article is about the British House of Lords. ... The University of Cambridge is an institute of higher learning. ...


The British Disability Discrimination Act 1995 also covers dyslexia. The Disability Discrimination Act 1995 (DDA 1995) is a UK parliamentary act of 1995, which makes it unlawful to discriminate against people in respect of their disabilities in relation to employment, the provision of goods and services, education and transport. ...

"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

“Stutter” redirects here. ...

Controversy

Some disagreement exists as to whether dyslexia does indeed exist as a condition, or whether it simply reflects individual differences among different readers.


"The Dyslexia Myth" is a documentary that appeared as part of the Dispatches series produced by British broadcaster Channel 4.[71] First aired in September 2005, it claims to expose myths and misconceptions that surround dyslexia. It argues that the common understanding of dyslexia is not only false but makes it more difficult to provide the reading help that hundreds of thousands of children desperately need. Drawing on years of intensive academic research on both sides of the Atlantic, it challenged the existence of dyslexia as a separate condition, and highlighted the many different forms of reading style. Dispatches is a long running British television documentary series on Channel 4. ... This article is about the British television station. ...


The documentary only focused on the reading difficulties that dyslexics encounter. As discussed in previous headings, dyslexia is more than a mere reading disability, and commonly includes symptoms that extend beyond reading difficulties. However, these symptoms are not included in the DSM-IV list of symptoms by which "Reading Disorder" is diagnosed (USA). The Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, is the handbook used most often in diagnosing mental disorders in the United States and other countries. ...


Julian Elliott, a psychologist at Durham University in the UK, disputes the characterization of dyslexia as a medical condition, and believes it should be treated simply as a reading difficulty. According to Elliot, "[parents] don’t want their child to be considered lazy, thick or stupid. If they get called this medically diagnosed term, dyslexic, then it is a signal to all that it’s not to do with intelligence.”[72] Elliot believes that children of all levels of intelligence may struggle with learning to read, and that all can be helped by educational strategies appropriate to their needs. He feels that resources are wasted on diagnosis and testing, and favors early intervention programs for all struggling readers.[73]


However, John Everatt of the University of Surrey, also in the UK, has demonstrated that dyslexic students can be distinguished from other children with low reading achievement by testing geared to assessing their strengths as well as weaknesses. Dyslexic children tend to score significantly better than other children, including non-impaired children, on tests of creativity, spatial memory, and spatial reasoning. Dyslexic children also perform better than other reading-impaired children on tests of vocabulary and listening comprehension. Everatt suggests that dyslexic children may be better served by educational intervention which includes strategies geared to their unique strengths in addition to skill remediation, and thus recommends more comprehensive evaluation and targeted interventions. [74] In neuroscience, spatial memory is the part of memory responsible for recording information about ones environment and its spatial orientation. ... It has been suggested that this article or section be merged into Visual thinking. ...


See also

This article or section does not cite its references or sources. ...

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  60. ^ Clark, Diana B, et.al. (2005). Dyslexia: Theory and Practice of Remedial Instruction. York Press. 
  61. ^ Shaywitz, B.; Shaywitz, S.; Blachman, B.; Pugh, K.R.; Fulbright, R.; Skudlarski, P.; Others, (2004). "Development of left occipitotemporal systems for skilled reading following a phonologically based intervention in children". Biological Psychiatry 55: 926-933. 
  62. ^ Eden, G.F.; Jones, K.M.; Cappell, K.; Gareau, L.; Wood, F.B.; Zeffiro, T.A.; Dietz, N.A.E.; Agnew, J.A.; Flowers, D.L. (2004). "Neural Changes following Remediation in Adult Developmental Dyslexia". Neuron 44 (3): 411-422. Retrieved on 2007-07-18. 
  63. ^ Dahms, Joel. (2006). "Spelling Out Dyslexia". Northwest Science & Technology. 
  64. ^ Reid, Gavin (2005). Dyslexia A Complete Guide for Parents. Chichester: John Wiley and Sons, 213. ISBN 0 470 86312 9. 
  65. ^ Shaywitz, Sally E.; Bennett A. Shaywitz (August 2001). "The Neurobiology of Reading and Dyslexia". Focus on Basics 5 (A). National Center for the Study of Adult Learning and Literacy. 
  66. ^ Learning Disabilities: Multidisciplinary Research Centers, NIH Guide, Volume 23, Number 37, October 21, 1994, Full Text HD-95-005 ("LDRC longitudinal, epidemiological studies show that RD (dyslexia) affect at least 10 million children, or approximately 1 child in 5.")
  67. ^ Brent Bowers. "Tracing Business Acumen to Dyslexia", New York Times, December 6, 2007.  Cites a study by by Julie Logan, professor of entrepreneurship at Cass Business School in London, among other literature.
  68. ^ Dyslexia Workshop Topics. Alabama Scottish Rite Foundation Learning Centers. Retrieved on June 6, 2006.
  69. ^ Scottish Rite Masonic Children's Learning Centers. Retrieved on June 6, 2006.
  70. ^ Scottish Rite Philanthropy. The Scottish Rite Bodies of Austin. Retrieved on June 6, 2006.
  71. ^ The Dyslexia Myth. Dispatches. Channel 4.
  72. ^ Blair, Alexandra. "Dyslexia ‘is used by parents as excuse for slow children’'", Times Newspapers Ltd(United Kingdom), May 28, 2007. Retrieved on 2007-05-29. 
  73. ^ "Is dyslexia just a myth?", Guardian Unlimited, September 7, 2005. Retrieved on 2007-05-29. 
  74. ^ Everatt, John; Weeks, Sally; Brooks, Peter (23 Jul 2007 (online)). "Profiles of Strengths and Weaknesses in Dyslexia and Other Learning Difficulties". Dyslexia (In Press). John Wiley & Sons. doi:10.1002/dys.342. Retrieved on 2007-07-26. 

2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance with the Gregorian calendar. ... is the 111th day of the year (112th in leap years) in the Gregorian calendar. ... is the 98th day of the year (99th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance with the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance with the Gregorian calendar. ... is the 116th day of the year (117th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 162nd day of the year (163rd in leap years) in the Gregorian calendar. ... Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ... is the 306th day of the year (307th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 159th day of the year (160th in leap years) in the Gregorian calendar. ... Year 1994 (MCMXCIV) The year 1994 was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by the United Nations. ... is the 228th day of the year (229th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 168th day of the year (169th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 168th day of the year (169th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 168th day of the year (169th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 192nd day of the year (193rd in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 147th day of the year (148th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... ISSN, or International Standard Serial Number, is the unique eight-digit number applied to a periodical publication including electronic serials. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 163rd day of the year (164th in leap years) in the Gregorian calendar. ... is the 47th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 147th day of the year (148th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 279th day of the year (280th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 279th day of the year (280th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 157th day of the year (158th in leap years) in the Gregorian calendar. ... ISSN, or International Standard Serial Number, is the unique eight-digit number applied to a periodical publication including electronic serials. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 166th day of the year (167th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 212th day of the year (213th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 199th day of the year (200th in leap years) in the Gregorian calendar. ... is the 294th day of the year (295th in leap years) in the Gregorian calendar. ... Year 1994 (MCMXCIV) The year 1994 was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by the United Nations. ... The New York Times is an internationally known daily newspaper published in New York City and distributed in the United States and many other nations worldwide. ... The Cass Business School of London (officially the Sir John Cass Business School, City of London) is a business school located in the City of London, England, and is part of The City University, London. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 149th day of the year (150th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 149th day of the year (150th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 207th day of the year (208th in leap years) in the Gregorian calendar. ...

External links

Historical

  • Samuel T Orton and June L Orton Personal Papers and Manuscripts at the Columbia University Health Science Library collection

Research papers, articles and media

Regional associations and organizations

Support groups and organizations

  • LD Online A service of public television station WETA in Washington, D.C., in association the National Joint Committee on Learning Disabilities (US)
  • Help for Parents of Dyslexic Children
  • 'The Mathematician Who Can't Add Up' Emma King

Freeview 'Snapshot' video by the Vega Science Trust


Dyslexia assistance solutions

  • Ghotit An online contextual speller for dyslectics.
The International Statistical Classification of Diseases and Related Health Problems (commonly known by the abbreviation ICD) is a detailed description of known diseases and injuries. ... Mental disorder or mental illness are terms used to refer psychological pattern that occurs in an individual and is usually associated with distress or disability that is not expected as part of normal development or culture. ... Emotional and behavioral disorders (EBD) is a broad category which is mostly being used in an educational context to group a range of more specific perceived difficulties of children and adolescents. ... For other uses, see Dementia (disambiguation). ... Multi-infarct dementia, also known as vascular dementia, is a form of dementia resulting from brain damage caused by stroke or transient ischemic attacks (also known as mini-strokes). ... Pick’s disease, also known as Pick disease and PiD, is a rare fronto-temporal neurodegenerative disease. ... Creutzfeldt-Jakob disease (CJD) is a very rare and incurable degenerative neurological disorder (brain disease) that is ultimately fatal. ... AIDS dementia complex (ADC; also known as HIV dementia, HIV encephalopathy and HIV-associated dementia) has become a common neurological disorder associated with HIV infection and AIDS. It is is a metabolic encephalopathy induced by HIV infection and fueled by immune activation of brain macrophages and microglia. ... Fronto-temporal dementias selectively affect the frontal lobe of the brain. ... This article is about the mental state and medical condition. ... Post-concussion syndrome, also known as postconcussive syndrome or PCS, is a set of symptoms that a person may experience for weeks, months, or even years after a concussion, a mild form of traumatic brain injury. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... A psychoactive drug or psychotropic substance is a chemical that alters brain function, resulting in temporary changes in perception, mood, consciousness, or behaviour. ... This article does not cite any references or sources. ... The Drunkenness of Noah by Giovanni Bellini Drunkenness is the state of being intoxicated by consumption of alcohol to a degree that mental and physical faculties are noticeably impaired. ... This article needs cleanup. ... For the beer, see Delirium Tremens (beer). ... Korsakoffs syndrome (Korsakoffs psychosis, amnesic-confabulatory syndrome), is a degenerative brain disorder caused by the lack of thiamine (vitamin B1) in the brain. ... This article needs cleanup. ... An opioid is a chemical substance that has a morphine-like action in the body. ... Opioid dependency is a medical diagnosis characterized by an individuals inability to stop using opioids even when objectively in his or her best interest to do so. ... A sedative is a substance that depresses the central nervous system (CNS), resulting in calmness, relaxation, reduction of anxiety, sleepiness, and slowed breathing, as well as slurred speech, staggering gait, poor judgment, and slow, uncertain reflexes. ... Hypnotic drugs are a class of drugs that induce sleep, used in the treatment of severe insomnia. ... Benzodiazepine withdrawal syndrome, caused by withdrawal or dosage reduction of benzodiazepines, is the symptoms which appear when a patient who has taken the drug for a period of time stops taking the drug. ... For other uses, see Cocaine (disambiguation). ... Cocaine dependence (or addiction) is physical and psychological dependency on the regular use of cocaine. ... ... Comparison of the perceived harm for various psychoactive drugs from a poll among medical psychiatrists specialized in addiction treatment[1] This article is an overview of the nontherapeutic use of alcohol and drugs of abuse. ... Physical dependence refers to a state resulting from habitual use of a drug, where negative physical withdrawal symptoms result from abrupt discontinuation. ... Withdrawal, also known as withdrawal syndrome, refers to the characteristic signs and symptoms that appear when a drug that causes physical dependence is regularly used for a long time and then suddenly discontinued or decreased in dosage. ... For other uses, see Psychosis (disambiguation). ... Disorganized schizophrenia is a subtype of schizophrenia as defined in the Diagnostic and Statistical Manual of Mental Disorders. ... Schizophreniform disorder is characterized by the presence of criterion A symptoms of schizophrenia. ... Schizotypal personality disorder, or simply schizotypal disorder, is a personality disorder that is characterized by a need for social isolation, odd behaviour and thinking, and often unconventional beliefs such as being convinced of having extra sensory abilities. ... Delusional disorder is a psychiatric diagnosis denoting a psychotic mental illness that involves holding one or more non-bizarre delusions in the absence of any other significant psychopathology (signs or symptoms of mental illness). ... Folie à deux (literally, a madness shared by two) is a rare psychiatric syndrome in which a symptom of psychosis (particularly a paranoid or delusional belief) is transmitted from one individual to another. ... A mood disorder is a condition whereby the prevailing emotional mood is distorted or inappropriate to the circumstances. ... This article is an expansion of a section entitled Mania from within the main article Bipolar disorder. ... For other uses, see Bipolar. ... On the Threshold of Eternity. ... Cyclothymia is a mood disorder. ... Dysthymia is a mood disorder that falls within the depression spectrum. ... A neurosis, in psychoanalytic theory, is an ineffectual coping strategy that Sigmund Freud suggested was caused by emotions from past experience overwhelming or interfering with present experience. ... In medical terms, stress is the disruption of homeostasis through physical or psychological stimuli. ... Anxiety disorder is a blanket term covering several different forms of abnormal, pathological anxiety, fears, phobias. ... Agoraphobia is an anxiety disorder precipitated by the fear of having a symptom attack or panic attack in a setting from which there is no easy means of escape. ... Panic Disorder is a psychiatric condition characterized by recurring panic attacks in combination with significant behavioral change or at least a month of ongoing worry about the implications or concern about having other attacks. ... Panic attacks are sudden, discrete periods of intense anxiety, fear and discomfort that are associated with a variety of somatic and cognitive symptoms[1]. The onset of these episodes is typically abrupt, and may have no obvious trigger. ... Generalized anxiety disorder (GAD) is an anxiety disorder that is characterized by excessive, uncontrollable and often irrational worry about everyday things, which is disproportionate to the actual source of worry. ... Social anxiety is an experience of fear, apprehension or worry regarding social situations and being evaluated by others. ... Social phobia (DSM-IV 300. ... OCD redirects here. ... Acute stress reaction is a psychological condition arising in response to a terrifying event. ... Post-traumatic stress disorder (PTSD) is a term for certain severe psychological consequences of exposure to, or confrontation with, stressful events that the person experiences as highly traumatic. ... In psychology, adjustment disorder refers to a psychological disturbance that develops in response to a stressor. ... Conversion Disorder is a DSM-IV diagnosis which describes neurological symptoms such as extreme weakness, paralysis, sensory disturbance, seizure and/or attacks that may resemble a known organic disease such as epilepsy or dystonia, but which cannot be currently attributed to neurological disease. ... Ganser syndrome is a psychiatric disorder characterised by approximate answers to questions. ... Somatization disorder (or Briquets disorder) is a type of mental illness in which a patient manifests a psychiatric condition as a physical complaint. ... Body dysmorphic disorder (BDD) is a mental disorder that involves a distorted body image. ... Hypochondria (sometimes hypochondriasis) is the unfounded belief that one is suffering from a serious illness. ... The English suffix -phobia is used to describe fear or hatred (the latter is often ignored) of a particular thing or subject. ... Da Costas Syndrome is a type of anxiety disorder first observed in soldiers in the American Civil War. ... This page is a candidate to be moved to Wikiquote. ... Neurasthenia was a term first coined by George Miller Beard in 1869 to describe a condition with symptoms of fatigue, anxiety and pessimism. ... For other uses, see Anorexia. ... Bulimia nervosa is an eating disorder characterised by recurrent binge eating, followed by compensatory behaviors, referred to as purging.[1] The most common form—practised more than 75% of people with bulimia nervosa—is self-induced vomiting; fasting, the use of laxatives, enemas, diuretics, and overexercising are also common. ... Dyssomnias are a broad classification of sleeping disorder that make it difficult to get to sleep, or to stay sleeping. ... This article is about the sleeping disorder. ... Hypersomnia, also known as excessive daytime sleepiness (EDS), is excessive amount of sleepiness. ... A parasomnia is any sleep disorder such as sleepwalking, sleepeating, sleep sex, teeth grinding, night terrors, rhythmic movement disorder, REM behaviour disorder, restless leg syndrome, and somniloquy (or sleep talking), characterized by partial arousals during sleep or during transitions between wakefulness and sleep. ... For other uses, see Night Terror. ... The current usage of the term nightmare refers to a dream which causes the sleeper a strong unpleasant emotional response. ... Sexual dysfunction or sexual malfunction (see also sexual function) is difficulty during any stage of the sexual act (which includes desire, arousal, orgasm, and resolution) that prevents the individual or couple from enjoying sexual activity. ... Erectile dysfunction (ED) or impotence is a sexual dysfunction characterized by the inability to develop or maintain an erection of the penis. ... Premature ejaculation (PE), also known as rapid ejaculation, premature climax or early ejaculation, is the most common sexual problem in men, affecting 25%-40% of men. ... Vaginismus is a condition which affects a womans ability to engage in any form of vaginal penetration, including sexual penetration, insertion of tampons, and the penetration involved in gynecological examinations. ... Dyspareunia is painful sexual intercourse, due to medical or psychological causes. ... Satyriasis redirects here. ... Postnatal Depression (also called Postpartum Depression and referred throughout this article by the acronym PPD) is a form of clinical depression which can affect women, and less frequently men, after childbirth. ... Wikinews has related news: Dr. Joseph Merlino on sexuality, insanity, Freud, fetishes and apathy Personality disorder, formerly referred to as a Character Disorder is a class of mental disorders characterized by rigid and on-going patterns of thought and action (Cognitive modules). ... Passive-aggressive behavior refers to passive, sometimes obstructionist resistance to following authoritative instructions in interpersonal or occupational situations. ... Kleptomania (Greek: κλέπτειν, kleptein, to steal, μανία, mania) is an inability or great difficulty in resisting impulses of stealing. ... Trichotillomania (TTM), or trich as it is commonly known, is an impulse control disorder characterized by the repeated urge to pull out scalp hair, eyelashes, facial hair, nose hair, pubic hair, eyebrows or other body hair. ... “Voyeur” redirects here. ... A factitious disorder or FD is a mental disorder where the ill individuals symptoms are either self-induced or falsified by the patient. ... This page refers to the self-inflicted factitious disorder. ... Egodystonic sexual orientation is an egodystonic condition. ... Two women in handcuffs and latex miniskirts and tops - Latex and PVC fetishism Wikinews has related news: Dr. Joseph Merlino on sexuality, insanity, Freud, fetishes and apathy Sexual fetishism is the sexual attraction for material and terrestrial objects while in reality the essence of the object is inanimate and sexless. ... Half-wit redirects here. ... Developmental disorders are disorders that occur at some stage in a childs development, often retarding the development. ... Specific developmental disorders categorizes specific learning disabilities and developmental disorders affecting coordination. ... Speech disorders or speech impediments, as they are also called, are a type of communication disorders where normal speech is disrupted. ... Expressive language disorder (DSM 315. ... For other uses, see Aphasia (disambiguation). ... Expressive aphasia, known as Brocas aphasia in clinical neuropsychology and agrammatic aphasia in cognitive neuropsychology, is an aphasia caused by damage to Brocas area in the brain. ... Receptive aphasia, also known as Wernickes aphasia, Fluent aphasia or sensory aphasia in clinical neuropsychology and cognitive neuropsychology, is a type of aphasia often (but not always) caused by neurological damage to Wernickes area in the brain. ... Landau-Kleffner syndrome (LKS), also called progressive epileptic aphasia, is a rare, childhood neurological syndrome characterized by the sudden or gradual development of aphasia (the inability to understand or express language) and an abnormal electroencephalogram (EEG). ... For the programming language, see Lisp (programming language). ... Dysgraphia (or agraphia) is a deficiency in the ability to write, regardless of the ability to read, not due to intellectual impairment. ... Gerstmann syndrome is a neurological disorder. ... Developmental Dyspraxia is one or all of a heterogeneous range of psychological development disorders affecting the initiation, organization and performance of action[1]. It entails the partial loss of the ability to coordinate and perform certain purposeful movements and gestures in the absence of motor or sensory impairments. ... The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), refers to a group of disorders characterized by delays in the development of multiple basic functions including socialization and communication. ... Autism is a brain development disorder characterized by impairments in social interaction and communication, and restricted and repetitive behavior, all exhibited before a child is three years old. ... Rett syndrome/ disorder is a neurodevelopmental disorder that is classified as a pervasive developmental disorder by the DSM-IV. Many[1] argue that this is a misclassification just as it would be to include such disorders as fragile X syndrome, tuberous sclerosis, or Down syndrome where one can see autistic... Asperger syndrome (also Aspergers syndrome, Aspergers disorder, Aspergers, or AS) is one of several autism spectrum disorders (ASD) characterized by difficulties in social interaction and by restricted and stereotyped interests and activities. ... Attention-Deficit Hyperactivity Disorder (ADHD), is a neurobehavioural developmental disorder[1] [2] [3] affecting about 3-5% of the worlds population under the age of 19[4]. It typically presents itself during childhood, and is characterized by a persistent pattern of inattention and/or hyperactivity, as well as forgetfulness... Conduct disorder is a psychiatric category to describe a pattern of repetitive behavior where the rights of others or the social norms are violated. ... Oppositional defiant disorder is a controversial psychiatric category listed in the Diagnostic and Statistical Manual of Mental Disorders where it is described as an ongoing pattern of disobedient, hostile, and defiant behavior toward authority figures that goes beyond the bounds of normal childhood behavior. ... Separation Anxiety redirects here. ... Selective mutism is a social anxiety disorder in which a person who is normally capable of speech is unable to speak in given situations. ... Reactive attachment disorder (RAD) is the diagnostic term for severe and relatively uncommon disorders of attachment that can affect children. ... A tic is a repeated, impulsive action, almost reflexive in nature, which the actor feels powerless to control or avoid. ... “Tourette” redirects here. ... Speech disorders or speech impediments, as they are also called, are a type of communication disorders where normal speech is disrupted. ... “Stutter” redirects here. ... Cluttering (also called tachyphemia) is a communicative disorder characterized by speech that is difficult for listeners to understand due to rapid speaking rate, erratic rhythm, poor syntax or grammar, and words or groups of words unrelated to the sentence. ... A symptom is a manifestation of a disease, indicating the nature of the disease, which is noticed by the patient. ... In medicine, a sign is a feature of disease as detected by the doctor during physical examination of a patient. ... Bold text This article does not cite any references or sources. ... The word voice can be used to refer to: Sound: The human voice. ... // R00-R99 - Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R09) Symptoms and signs involving the circulatory and respiratory systems (R00) Abnormalities of heart beat (R000) Tachycardia, unspecified (R001) Bradycardia, unspecified (R002) Palpitations (R008) Other and unspecified abnormalities of heart beat (R01) Cardiac murmurs and other... For other uses, see Aphasia (disambiguation). ... Dysphasia should not be confused with the similarly pronounced dysphagia, which is a difficulty swallowing. ... Expressive aphasia, known as Brocas aphasia in clinical neuropsychology and agrammatic aphasia in cognitive neuropsychology, is an aphasia caused by damage to Brocas area in the brain. ... Receptive aphasia, also known as Wernickes aphasia, Fluent aphasia or sensory aphasia in clinical neuropsychology and cognitive neuropsychology, is a type of aphasia often (but not always) caused by neurological damage to Wernickes area in the brain. ... Conduction aphasia is a relatively rare form of aphasia, caused by damage to the nerve fibres connecting Wernickes and Brocas areas (arcuate fasciculus). ... Speech disorders or speech impediments, as they are also called, are a type of communication disorders where normal speech is disrupted. ... Look up dysarthria in Wiktionary, the free dictionary. ... This article or section does not cite its references or sources. ... Alexia (from the Greek , privative, expressing negation, and = word) is an acquired type of sensory aphasia where damage to the brain causes a patient to lose the ability to read. ... Agnosia (a-gnosis, non-knowledge, or loss of knowledge) is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss[1][2]. It is usually associated with brain injury or neurological illness, particularly after... Prosopagnosia (sometimes known as face blindness) is disorder of face perception where the ability to recognize faces is impaired, while the ability to recognize objects may be relatively intact. ... Apraxia is a neurological disorder characterized by loss of the ability to execute or carry out learned (familiar) movements, despite having the desire and the physical ability to perform the movements. ... This article or section is in need of attention from an expert on the subject. ... Dysgraphia (or agraphia) is a deficiency in the ability to write, regardless of the ability to read, not due to intellectual impairment. ... Speech disorders or speech impediments, as they are also called, are a type of communication disorders where normal speech is disrupted. ... Lisp may mean: Lisp programming language Lisp (speech) This is a disambiguation page — a list of pages that otherwise might share the same title. ... Aphasia is a loss or impairment of the ability to produce or comprehend language, due to brain damage. ...

  Results from FactBites:
 
dyslexia: Definition and Much More from Answers.com (6237 words)
Dyslexia is a classical primary reading disorder and should be differentiated from secondary disorders such as mental retardation, educational or environmental deprivation, or physical/organic diseases.
A third type of dyslexia is referred to as "secondary"or "developmental dyslexia" and is felt to be causedby hormonal development during the early stages of fetal development.Developmental dyslexia diminishes as the child matures.
Dyslexia should not be confused with dyscalculia, a learning disability marked by severe difficulties with mathematics.
Dyslexia (1187 words)
Children with dyslexia may also try to read from right to left, may fail to see (and occasionally to hear) similarities and differences in letters and words, may not recognize the spacing that organizes letters into separate words, and may be unable to sound out the pronunciation of an unfamiliar word.
Dyslexia seems to be caused by a malfunction in certain areas of the brain concerned with language.
Dyslexia is characterized by a delay in the age at which your child begins to read.
  More results at FactBites »

 
 

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