Dyslexia, also known until the 1960s as word blindness, is a disorder characterized by reading below the expected level for one's age.
Different people are affected to different degrees.
[ Problems may include difficulties in ]spelling
Spelling is a set of conventions that regulate the way of using graphemes (writing system) to represent a language in its written form. In other words, spelling is the rendering of speech sound (phoneme) into writing (grapheme). Spelling is one ...
words, reading quickly, writing words, "sounding out" words in the head, pronouncing words when reading aloud and understanding what one reads.[ Often these difficulties are first noticed at school.] The difficulties are involuntary, and people with this disorder have a normal desire to learn
Learning is the process of acquiring new understanding, knowledge, behaviors, skills, values, attitudes, and preferences. The ability to learn is possessed by humans, animals, and some machines; there is also evidence for some kind of learn ...
. People with dyslexia have higher rates of attention deficit hyperactivity disorder
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inap ...
(ADHD), developmental language disorder
Developmental language disorder (DLD) is identified when a child has problems with language development that continue into school age and beyond. The language problems have a significant impact on everyday social interactions or educational progre ...
s, and difficulties with numbers.[
Dyslexia is believed to be caused by the ]interaction
Interaction is action that occurs between two or more objects, with broad use in philosophy and the sciences. It may refer to:
Science
* Interaction hypothesis, a theory of second language acquisition
* Interaction (statistics)
* Interactions o ...
of genetic and environmental factors. Some cases run in families. Dyslexia that develops due to a traumatic brain injury
A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury TBI/concussionto severe traumatic br ...
, stroke, or dementia
Dementia is a disorder which manifests as a set of related symptoms, which usually surfaces when the brain is damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, which negatively affe ...
is sometimes called "acquired dyslexia" or alexia.[ The underlying mechanisms of dyslexia result from differences within the brain's language processing.] Dyslexia is diagnosed through a series of tests of memory, vision, spelling, and reading skills. Dyslexia is separate from reading difficulties caused by hearing
Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is audit ...
or vision problem
Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment†...
s or by insufficient teaching
Teaching is the practice implemented by a ''teacher'' aimed at transmitting skills (knowledge, know-how, and interpersonal skills) to a learner, a student, or any other audience in the context of an educational institution. Teaching is closely ...
or opportunity to learn.
Treatment involves adjusting teaching methods to meet the person's needs.[ While not curing the underlying problem, it may decrease the degree or impact of symptoms. Treatments targeting vision are not effective.] Dyslexia is the most common learning disability and occurs in all areas of the world. It affects 3–7% of the population; however, up to 20% of the general population may have some degree of symptoms. While dyslexia is more often diagnosed in boys, this is partly explained by a self-fulfilling referral bias among teachers and professionals.[ It has even been suggested that the condition affects men and women equally.][ Some believe that dyslexia is best considered as a different way of learning, with both benefits and downsides.
]
Classification
Dyslexia is divided into developmental and acquired forms. Acquired dyslexia occurs subsequent to neurological insult, such as traumatic brain injury
A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury TBI/concussionto severe traumatic br ...
or stroke. People with acquired dyslexia exhibit some of the signs or symptoms of the developmental disorder, but require different assessment strategies and treatment approaches. ''Pure alexia'', also known as ''agnosic alexia'' or ''pure word blindness'', is one form of alexia which makes up "the peripheral dyslexia" group.
Signs and symptoms
In early childhood, symptoms that correlate with a later diagnosis of dyslexia include delayed onset of speech and a lack of phonological awareness
Phonological awareness is an individual's awareness of the phonological structure, or sound structure, of words. Phonological awareness is an important and reliable predictor of later reading ability and has, therefore, been the focus of much res ...
.[ A common myth closely associates dyslexia with ]mirror writing
Mirror writing is formed by writing in the direction that is the reverse of the natural way for a given language, such that the result is the mirror image of normal writing: it appears normal when it is reflected in a mirror. It is sometimes u ...
and reading letters or words backwards. These behaviors are seen in many children as they learn to read and write, and are not considered to be defining characteristics of dyslexia.[
School-age children with dyslexia may exhibit signs of difficulty in identifying or generating rhyming words, or counting the number of syllables in words—both of which depend on phonological awareness.] They may also show difficulty in segmenting words into individual sounds (such as sounding out the three sounds of ''k'', ''a'', and ''t'' in ''cat'') or may struggle to blend sounds, indicating reduced phonemic awareness
Phonemic awareness is a subset of phonological awareness in which listeners are able to hear, identify and manipulate phonemes, the smallest mental units of sound that help to differentiate units of meaning ( morphemes). Separating the spoken w ...
.
Difficulties with word retrieval or naming things is also associated with dyslexia. People with dyslexia are commonly poor spellers, a feature sometimes called ''dysorthographia'' or '' dysgraphia'', which depends on the skill of orthographic coding.
Problems persist into adolescence and adulthood and may include difficulties with summarizing stories, memorization, reading aloud, or learning foreign languages. Adults with dyslexia can often read with good comprehension, though they tend to read more slowly than others without a learning difficulty and perform worse in spelling
Spelling is a set of conventions that regulate the way of using graphemes (writing system) to represent a language in its written form. In other words, spelling is the rendering of speech sound (phoneme) into writing (grapheme). Spelling is one ...
tests or when reading nonsense words—a measure of phonological awareness.
Associated conditions
Dyslexia often co-occurs with other learning disorders, but the reasons for this comorbidity have not been clearly identified. These associated disabilities include:
; Dysgraphia: A disorder involving difficulties with writing
Writing is a medium of human communication which involves the representation of a language through a system of physically inscribed, mechanically transferred, or digitally represented symbols.
Writing systems do not themselves constitute h ...
or typing
Typing is the process of writing or inputting text by pressing keys on a typewriter, computer keyboard, mobile phone or calculator. It can be distinguished from other means of text input, such as handwriting and speech recognition. Text can b ...
, sometimes due to problems with eye–hand coordination
Eye–hand coordination (also known as hand–eye coordination) is the coordinated control of eye movement with hand movement and the processing of visual input to guide reaching and grasping along with the use of proprioception of the hands to ...
; it also can impede direction- or sequence-oriented processes, such as tying knots or carrying out repetitive tasks. In dyslexia, dysgraphia is often multifactorial, due to impaired letter-writing automaticity
Automaticity is the ability to do things without occupying the mind with the low-level details required, allowing it to become an automatic response pattern or habit. It is usually the result of learning, repetition, and practice. Examples of tas ...
, organizational and elaborative difficulties, and impaired visual word forming, which makes it more difficult to retrieve the visual picture of words required for spelling.[
; ]Attention deficit hyperactivity disorder
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inap ...
(ADHD): A disorder characterized by problems sustaining attention, hyperactivity, or acting impulsively. Dyslexia and ADHD commonly occur together. Approximately 15% or 12–24% of people with dyslexia have ADHD; and up to 35% of people with ADHD have dyslexia.
; Auditory processing disorder
Auditory processing disorder (APD), rarely known as King-Kopetzky syndrome or auditory disability with normal hearing (ADN), is a neurodevelopmental disorder affecting the way the brain processes auditory information. Individuals with APD usually ...
: A listening disorder that affects the ability to process auditory information. This can lead to problems with auditory memory and auditory sequencing. Many people with dyslexia have auditory processing problems, and may develop their own logographic cues
Logographic cues are visual images embedded with specific, widely understood meaning; they are pictures that represent certain words or concepts. These pictures are "designed to offer readers a high-utility message in a minimum amount of space." S ...
to compensate for this type of deficit. Some research suggests that auditory processing skills could be the primary shortfall in dyslexia.
; Developmental coordination disorder
Developmental coordination disorder (DCD), also known as developmental motor coordination disorder, developmental dyspraxia or simply dyspraxia from the word 'praxis' meaning to do or act, is a neurodevelopmental disorder characterized by impaire ...
: A neurological condition characterized by difficulty in carrying out routine tasks involving balance, fine- motor control and kinesthetic
Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense".
Proprioception is mediated by proprioceptors, mechanosensory neurons ...
coordination; difficulty in the use of speech sounds; and problems with short-term memory and organization.
Causes
Researchers have been trying to find the neurobiological basis of dyslexia since the condition was first identified in 1881. For example, some have tried to associate the common problem among people with dyslexia of not being able to see letters clearly to abnormal development of their visual nerve cells.
Neuroanatomy
Neuroimaging
Neuroimaging is the use of quantitative (computational) techniques to study the structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive manner. Incr ...
techniques, such as functional magnetic resonance imaging (fMRI
Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area ...
) and positron emission tomography (PET), have shown a correlation between both functional and structural differences in the brains of children with reading difficulties. Some people with dyslexia show less electrical activation in parts of the left hemisphere of the brain involved with reading, such as the inferior frontal gyrus
The inferior frontal gyrus (IFG), (gyrus frontalis inferior), is the lowest positioned gyrus of the frontal gyri, of the frontal lobe, and is part of the prefrontal cortex.
Its superior border is the inferior frontal sulcus (which divides it f ...
, inferior parietal lobule
The inferior parietal lobule (subparietal district) lies below the horizontal portion of the intraparietal sulcus, and behind the lower part of the postcentral sulcus. Also known as Geschwind's territory after Norman Geschwind, an American neur ...
, and the middle and ventral temporal cortex.[ Over the past decade, brain activation studies using PET to study language have produced a breakthrough in the understanding of the neural basis of language. Neural bases for the visual lexicon and for auditory verbal short-term memory components have been proposed, with some implication that the observed neural manifestation of developmental dyslexia is task-specific (i.e., functional rather than structural). fMRIs of people with dyslexia indicate an interactive role of the cerebellum and cerebral cortex as well as other brain structures in reading.
The cerebellar theory of dyslexia proposes that impairment of cerebellum-controlled muscle movement affects the formation of words by the tongue and facial muscles, resulting in the fluency problems that some people with dyslexia experience. The cerebellum is also involved in the automatization of some tasks, such as reading. The fact that some children with dyslexia have motor task and balance impairments could be consistent with a cerebellar role in their reading difficulties. However, the cerebellar theory has not been supported by controlled research studies.
]
Genetics
Research into potential genetic causes of dyslexia has its roots in post-autopsy examination of the brains of people with dyslexia. Observed anatomical differences in the language center
In neuroscience and psychology, the term language center refers collectively to the areas of the brain which serve a particular function for speech processing and production. Language is a core system, which gives humans the capacity to solve dif ...
s of such brains include microscopic cortical malformations known as ectopias, and more rarely, vascular
The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away f ...
micro-malformations, and microgyrus—a smaller than usual size for the gyrus. The previously cited studies and others suggest that abnormal cortical development, presumed to occur before or during the sixth month of fetal
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal develo ...
brain development, may have caused the abnormalities. Abnormal cell formations in people with dyslexia have also been reported in non-language cerebral and subcortical brain structures. Several genes have been associated with dyslexia, including DCDC2 and KIAA0319 on chromosome 6, and DYX1C1
Dyslexia susceptibility 1 candidate gene 1 protein is a protein that in humans is encoded by the ''DYX1C1'' gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." ...
on chromosome 15
Chromosome 15 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 15 spans about 102 million base pairs (the building material of DNA) and represents between 3% and 3.5% of the total DN ...
.
Gene–environment interaction
The contribution of gene–environment interaction to reading disability has been intensely studied using twin studies
Twin studies are studies conducted on identical or fraternal twins. They aim to reveal the importance of environmental and genetic influences for traits, phenotypes, and disorders. Twin research is considered a key tool in behavioral genetics ...
, which estimate the proportion of variance associated with a person's environment and the proportion associated with their genes. Both environmental and genetic factors appear to contribute to reading development. Studies examining the influence of environmental factors such as parental education and teaching quality have determined that genetics have greater influence in supportive, rather than less optimal, environments. However, more optimal conditions may just allow those genetic risk factors to account for more of the variance in outcome because the environmental risk factors have been minimized.[
As environment plays a large role in learning and memory, it is likely that epigenetic modifications play an important role in reading ability. Measures of gene expression, ]histone modifications
In biology, histones are highly basic proteins abundant in lysine and arginine residues that are found in eukaryotic cell nuclei. They act as spools around which DNA winds to create structural units called nucleosomes. Nucleosomes in turn are w ...
, and methylation in the human periphery are used to study epigenetic processes; however, all of these have limitations in the extrapolation of results for application to the human brain.
Language
The orthographic complexity of a language directly affects how difficult it is to learn to read it.[
Paulesu, Eraldo; Brunswick, Nicola and Paganelli, Federica (2010). "Cross-cultural differences in unimpaired and dyslexic reading: Behavioral and functional anatomical observations in readers of regular and irregular orthographies. Chapter 12 i]
Reading and Dyslexia in Different Orthographies
. Eds. Nicola Brunswick, Siné McDougall, and Paul de Mornay Davies. Psychology Press. English and French have comparatively "deep" phonemic orthographies
A phonemic orthography is an orthography (system for writing a language) in which the graphemes (written symbols) correspond to the phonemes (significant spoken sounds) of the language. Natural languages rarely have perfectly phonemic orthographi ...
within the Latin alphabet
The Latin alphabet or Roman alphabet is the collection of letters originally used by the ancient Romans to write the Latin language. Largely unaltered with the exception of extensions (such as diacritics), it used to write English and th ...
writing system
A writing system is a method of visually representing verbal communication, based on a script and a set of rules regulating its use. While both writing and speech are useful in conveying messages, writing differs in also being a reliable fo ...
, with complex structures employing spelling patterns on several levels: letter-sound correspondence, syllables, and morpheme
A morpheme is the smallest meaningful constituent of a linguistic expression. The field of linguistic study dedicated to morphemes is called morphology.
In English, morphemes are often but not necessarily words. Morphemes that stand alone are ...
s. Languages such as Spanish, Italian and Finnish primarily employ letter-sound correspondence—so-called "shallow" orthographies—which makes them easier to learn for people with dyslexia. Logograph
In a written language, a logogram, logograph, or lexigraph is a written character that represents a word or morpheme. Chinese characters (pronounced '' hanzi'' in Mandarin, ''kanji'' in Japanese, ''hanja'' in Korean) are generally logograms, ...
ic writing systems, such as Chinese characters
Chinese characters () are logograms developed for the writing of Chinese. In addition, they have been adapted to write other East Asian languages, and remain a key component of the Japanese writing system where they are known as ''kanji ...
, have extensive symbol use; and these also pose problems for dyslexic learners.
Pathophysiology
For most people who are right-hand dominant, the left hemisphere of their brain is more specialized for language processing
Language processing refers to the way humans use words to communicate ideas and feelings, and how such communications are processed and understood. Language processing is considered to be a uniquely human ability that is not produced with the sa ...
. With regard to the mechanism of dyslexia, fMRI studies suggest that this specialization is less pronounced or absent in people with dyslexia. In other studies, dyslexia is correlated with anatomical differences in the corpus callosum
The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick nerve tract, consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental m ...
, the bundle of nerve fibers that connects the left and right hemispheres.
Data via diffusion tensor MRI indicate changes in connectivity or in gray matter density in areas related to reading and language. Finally, the left inferior frontal gyrus
The inferior frontal gyrus (IFG), (gyrus frontalis inferior), is the lowest positioned gyrus of the frontal gyri, of the frontal lobe, and is part of the prefrontal cortex.
Its superior border is the inferior frontal sulcus (which divides it f ...
has shown differences in phonological processing in people with dyslexia.[ Neurophysiological and imaging procedures are being used to ascertain phenotypic characteristics in people with dyslexia, thus identifying the effects of dyslexia-related genes.
]
Dual route theory
The dual-route theory of reading
Reading is the process of taking in the sense or meaning of letters, symbols, etc., especially by sight or touch.
For educators and researchers, reading is a multifaceted process involving such areas as word recognition, orthography (spelling ...
aloud was first described in the early 1970s. This theory suggests that two separate mental mechanisms, or cognitive routes, are involved in reading aloud. One mechanism is the lexical route, which is the process whereby skilled readers can recognize known words by sight alone, through a "dictionary" lookup procedure. The other mechanism is the nonlexical or sublexical route, which is the process whereby the reader can "sound out" a written word. This is done by identifying the word's constituent parts (letters, phonemes
In phonology and linguistics, a phoneme () is a unit of sound that can distinguish one word from another in a particular language.
For example, in most dialects of English, with the notable exception of the West Midlands and the north-west ...
, graphemes
In linguistics, a grapheme is the smallest functional unit of a writing system.
The word ''grapheme'' is derived and the suffix ''-eme'' by analogy with ''phoneme'' and other names of emic units. The study of graphemes is called ''graphemic ...
) and applying knowledge of how these parts are associated with each other, for example, how a string of neighboring letters sound together. The dual-route system could explain the different rates of dyslexia occurrence between different languages (e.g., the consistency of phonological rules in the Spanish language could account for the fact that Spanish-speaking children show a higher level of performance in non-word reading, when compared to English-speakers).
Diagnosis
Dyslexia is a heterogeneous, dimensional learning disorder that impairs accurate and fluent word reading and spelling. Typical—but not universal—features include difficulties with phonological awareness; inefficient and often inaccurate processing of sounds in oral language (''phonological processing''); and verbal working memory deficits.[Snowling, Margaret J. ''Dyslexia: A Very Short Introduction''. Oxford University Press, 2019. ]
Dyslexia is a neurodevelopmental disorder, subcategorized in diagnostic guides as a ''learning disorder with impairment in reading'' (ICD-11 prefixes "developmental" to "learning disorder"; DSM-5 uses "specific"). Dyslexia is not a problem with intelligence
Intelligence has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. More generally, it can be des ...
. Emotional problems often arise secondary to learning difficulties. The National Institute of Neurological Disorders and Stroke describes dyslexia as "difficulty with phonological processing (the manipulation of sounds), spelling, and/or rapid visual-verbal responding".
The British Dyslexia Association defines dyslexia as "a learning difficulty that primarily affects the skills involved in accurate and fluent word reading and spelling" and is characterized by "difficulties in phonological awareness, verbal memory and verbal processing speed". ''Phonological awareness'' enables one to identify, discriminate, remember (working memory
Working memory is a cognitive system with a limited capacity that can hold information temporarily. It is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-term memory, ...
), and mentally manipulate the sound structures of language—phonemes
In phonology and linguistics, a phoneme () is a unit of sound that can distinguish one word from another in a particular language.
For example, in most dialects of English, with the notable exception of the West Midlands and the north-west ...
, onsite-rime segments, syllables, and words.
Assessment
The following can be done to assess for dyslexia:
Apply a multidisciplinary team approach involving the child's parent(s) and teacher(s), school psychologist, pediatrician, and, as appropriate, speech and language pathologist (speech therapist), and occupational therapist
Occupational therapists (OTs) are health care professionals specializing in occupational therapy and occupational science. OTs and occupational therapy assistants (OTAs) use scientific bases and a holistic perspective to promote a person's abi ...
.
Gain familiarity with typical ages children reach various general developmental milestones, and domain-specific milestones, such as phonological awareness (recognizing rhyming words; identifying the initial sounds in words).
Do not rely on tests exclusively. Careful observation of the child in the school and home environments, and sensitive, comprehensive parental interviews are just as important as tests.
Look at the empirically supported response to intervention (RTI) approach, which "... involves monitoring the progress of a group of children through a programme of intervention rather than undertaking a static assessment of their current skills. Children with the most need are those who fail to respond to effective teaching, and they are readily identified using this approach."
Assessment tests
There is a wide range of tests that are used in clinical and educational settings to evaluate the possibility of dyslexia. If initial testing suggests that a person might have dyslexia, such tests are often followed up with a full diagnostic assessment to determine the extent and nature of the disorder. Some tests can be administered by a teacher or computer; others require specialized training and are given by psychologists.[ Some test results indicate how to carry out teaching strategies.][ Because a variety of different cognitive, behavioral, emotional, and environmental factors all could contribute to difficultly learning to read, a comprehensive evaluation should consider these different possibilities. These tests and observations can include:]
* General measures of cognitive ability, such as the Wechsler Intelligence Scale for Children
The Wechsler Intelligence Scale for Children (WISC) is an individually administered intelligence test for children between the ages of 6 and 16. The Fifth Edition (WISC-V; Wechsler, 2014) is the most recent version.
The WISC-V takes 45 to 65 minu ...
, Woodcock-Johnson Tests of Cognitive Abilities, or Stanford-Binet Intelligence Scales. Low general cognitive ability would make reading more difficult. Cognitive ability measures also often try to measure different cognitive processes, such as verbal ability, nonverbal and spatial reasoning, working memory, and processing speed. There are different versions of these tests for different age groups. Almost all of these require additional training to give and score correctly, and are done by psychologists. According to Mather and Schneider (2015), a confirmatory profile and/or pattern of scores on cognitive tests confirming or ruling-out reading disorder has not yet been identified.
* Screening or evaluation for mental health conditions: Parents and teachers can complete rating scales or behavior checklists to gather information about emotional and behavioral functioning for younger people. Many checklists have similar versions for parents, teachers, and younger people old enough to read reasonably well (often 11 years and older) to complete. Examples include the Behavioral Assessment System for Children, and the Strengths and Difficulties Questionnaire. All of these have nationally representative norms, making it possible to compare the level of symptoms to what would be typical for the younger person's age and biological sex. Other checklists link more specifically to psychiatric diagnoses, such as the Vanderbilt ADHD Rating Scales or the Screen for Child Anxiety Related Emotional Disorders (SCARED). Screening uses brief tools that are designed to catch cases with a disorder, but they often get false positive scores for people who do not have the disorder. Screeners should be followed up by a more accurate test or diagnostic interview as a result. Depressive disorders and anxiety disorders are two-three times higher in people with dyslexia, and attention-deficit/hyperactivity disorder is more common, as well.
* Review of academic achievement and skills: Average spelling/reading ability for a dyslexic is a percentage ranking <16, well below normal. In addition to reviewing grades and teacher notes, standardized test results are helpful in evaluating progress. These include group administered tests, such as the Iowa Tests of Educational Development, that a teacher may give to a group or whole classroom of younger people at the same time. They also could include individually administered tests of achievement, such as the Wide Range Achievement Test The Wide Range Achievement Test, currently in its fifth edition (WRAT5), is an achievement test which measures an individual's ability to read words, comprehend sentences, spell, and compute solutions to math problems.Wilkinson, G. S., & Robertso ...
, or the Woodcock-Johnson (which also includes a set of achievement tests). The individually administered tests again require more specialized training.
Screening
Screening procedures seek to identify children who show signs of possible dyslexia. In the preschool years, a family history of dyslexia, particularly in biological parents and siblings, predicts an eventual dyslexia diagnosis better than any test. In primary school (ages 5–7), the ideal screening procedure consists of training primary school teachers to carefully observe and record their pupils' progress through the phonics curriculum, and thereby identify children progressing slowly. When teachers identify such students they can supplement their observations with screening tests such as the ''Phonics screening check'' used by United Kingdom schools during Year one.
In the medical setting, child and adolescent psychiatrist M. S. Thambirajah emphasizes that " ven the high prevalence of developmental disorders in school-aged children, all children seen in clinics should be systematically screened for developmental disorders irrespective of the presenting problem/s." Thambirajah recommends screening for developmental disorders, including dyslexia, by conducting a brief developmental history, a preliminary psychosocial developmental examination, and obtaining a school report regarding academic and social functioning.
Management
Through the use of compensation strategies, therapy and educational support, individuals with dyslexia can learn to read and write. There are techniques and technical aids that help to manage or conceal symptoms of the disorder. Reducing stress and anxiety can sometimes improve written comprehension. For dyslexia intervention
Management of dyslexia depends on a multiple of variables; there is no one specific strategy or set of strategies which will work for all who have dyslexia.
Some teaching is geared to specific reading skill areas, such as phonetic decoding; whe ...
with alphabet-writing systems, the fundamental aim is to increase a child's awareness of correspondences between grapheme
In linguistics, a grapheme is the smallest functional unit of a writing system.
The word ''grapheme'' is derived and the suffix ''-eme'' by analogy with ''phoneme'' and other names of emic units. The study of graphemes is called '' graphemi ...
s (letters) and phoneme
In phonology and linguistics, a phoneme () is a unit of sound that can distinguish one word from another in a particular language.
For example, in most dialects of English, with the notable exception of the West Midlands and the north-wes ...
s (sounds), and to relate these to reading and spelling by teaching how sounds blend into words. Reinforced collateral training focused on reading and spelling may yield longer-lasting gains than oral phonological training alone. Early intervention can be successful in reducing reading failure.
Research does not suggest that specially-tailored fonts (such as Dyslexie and OpenDyslexic) help with reading. Children with dyslexia read text set in a regular font such as Times New Roman
Times New Roman is a serif typeface. It was commissioned by the British newspaper ''The Times'' in 1931 and conceived by Stanley Morison, the artistic adviser to the British branch of the printing equipment company Monotype, in collaboration w ...
and Arial
Arial (also called Arial MT) is a sans-serif typeface and set of computer fonts in the neo-grotesque style. Fonts from the Arial family are included with all versions of Microsoft Windows from Windows 3.1 on, some other Microsoft software ap ...
just as quickly, and they show a preference for regular fonts over specially-tailored fonts. Some research has pointed to increased letter-spacing
Examples of headline letter spacing
In typography, letter spacing, character spacing or tracking is an optically consistent adjustment to the space between letters to change the visual density of a line or block of text. Letter spacing is distin ...
being beneficial.
There is currently no evidence showing that music education significantly improves the reading skills of adolescents with dyslexia.
Prognosis
Dyslexic children require special instruction for word analysis and spelling from an early age. The prognosis, generally speaking, is positive for individuals who are identified in childhood and receive support from friends and family.[ The New York educational system (NYED) indicates "a daily uninterrupted 90-minute block of instruction in reading" and "instruction in phonemic awareness, phonics, vocabulary development, reading fluency" so as to improve the individual's reading ability.
]
Epidemiology
The prevalence of dyslexia is unknown, but it has been estimated to be as low as 5% and as high as 17% of the population. Dyslexia is diagnosed more often in males.[
There are different definitions of dyslexia used throughout the world. Further, differences in writing systems may affect development of written language ability due to the interplay between auditory and written representations of phonemes. Dyslexia is not limited to difficulty in converting letters to sounds, and Chinese people with dyslexia may have difficulty converting ]Chinese character
Chinese characters () are logograms developed for the writing of Chinese. In addition, they have been adapted to write other East Asian languages, and remain a key component of the Japanese writing system where they are known as ''kanj ...
s into their meanings. The Chinese vocabulary uses logographic, monographic, non-alphabet writing where one character can represent an individual phoneme.
The phonological-processing hypothesis attempts to explain why dyslexia occurs in a wide variety of languages. Furthermore, the relationship between phonological capacity and reading appears to be influenced by orthography.
History
Dyslexia was clinically described by Oswald Berkhan in 1881, but the term ''dyslexia'' was coined in 1883 by Rudolf Berlin, an ophthalmologist in Stuttgart.[Berlin, Rudolf. o title.''Medicinisches Correspondenzblatt des Württembergischen Ärztlichen Landesvereins'' orrespondence Sheet of the Württemberg Medical Association53 (1883): 209.][Webster's Third New International Dictionary. "History and Etymology for dyslexia", s.v. " dyslexia, noun". Springfield, MA: Merriam-Webster, 1961, rev. 2016.] He used the term to refer to the case of a young boy who had severe difficulty learning to read and write, despite showing typical intelligence and physical abilities in all other respects. In 1896, W. Pringle Morgan, a British physician from Seaford, East Sussex
Seaford is a town in East Sussex, England, east of Newhaven and west of Eastbourne.OS Explorer map Eastbourne and Beachy Head Scale: 1:25 000. Publisher:Ordnance Survey – Southampton B2 edition. Publishing Date:2009.
In the Middle Ages, Sea ...
, published a description of a reading-specific learning disorder in a report to the '' British Medical Journal'' titled "Congenital Word Blindness". The distinction between phonological versus surface types of dyslexia is only descriptive, and without any etiological assumption as to the underlying brain mechanisms. However, studies have alluded to potential differences due to variation in performance. Over time, we have changed from the intelligence-based model to the age-based model, in terms of those with Dyslexia.
Society and culture
As is the case with any disorder, society often makes an assessment based on incomplete information. Before the 1980s, dyslexia was thought to be a consequence of education, rather than a neurological disability. As a result, society often misjudges those with the disorder.[ There is also sometimes a workplace stigma and negative attitude towards those with dyslexia. If the instructors of a person with dyslexia lack the necessary training to support a child with the condition, there is often a negative effect on the student's learning participation.
Since at least the 1960s in the UK, the children diagnosed with developmental dyslexia have consistently been from privileged families.] Although half of prisoners in the UK have significant reading difficulties, very few have ever been evaluated for dyslexia. Access to some special educational resources and funding is contingent upon having a diagnosis of dyslexia. As a result, when Staffordshire and Warwickshire
Warwickshire (; abbreviated Warks) is a county in the West Midlands region of England. The county town is Warwick, and the largest town is Nuneaton. The county is famous for being the birthplace of William Shakespeare at Stratford-upon-Av ...
proposed in 2018 to teach reading to all children with reading difficulties, using techniques proven to be successful for most children with a diagnosis of dyslexia, without first requiring the families to obtain an official diagnosis, dyslexia advocates and parents of children with dyslexia were fearful that they were losing a privileged status.
Stigma and success
The stigma surrounding dyslexia is just beginning to be understood. As awareness increases, it is informative to observe the long list of notable people with dyslexia who have struggled and ended up with successful careers, among them Whoopi Goldberg
Caryn Elaine Johnson (born November 13, 1955), known professionally as Whoopi Goldberg (), is an American actor, comedian, author, and television personality.Kuchwara, Michael (AP Drama Writer)"Whoopi Goldberg: A One-Woman Character Parade". ' ...
, who said:
Their success was not without struggle. Henry Winkler said:
Research
Most dyslexia research relates to alphabetic writing systems, and especially to European languages
Most languages of Europe belong to the Indo-European language family. Out of a total European population of 744 million as of 2018, some 94% are native speakers of an Indo-European language. Within Indo-European, the three largest phyla are Ro ...
. However, substantial research is also available regarding people with dyslexia who speak Arabic, Chinese, Hebrew, or other languages. The outward expression of individuals with reading disability, and regular poor readers, is the same in some respects.
See also
* Dyscalculia
Dyscalculia () is a disability resulting in difficulty learning or comprehending arithmetic, such as difficulty in understanding numbers, learning how to manipulate numbers, performing mathematical calculations, and learning facts in mathematics. ...
, difficulty comprehending numbers and math
* Learning to read
Reading is the process of taking in the sense or meaning of letters, symbols, etc., especially by sight or touch.
For educators and researchers, reading is a multifaceted process involving such areas as word recognition, orthography (spellin ...
* Orton-Gillingham
References
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External links
{{Authority control
Literacy
Learning to read
Specific developmental disorders
*Dyslexia
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Writing