dyslexia

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Classification according to ICD-10
R48.0 Dyslexia and alexia
ICD-10 online (WHO version 2019)

Under dyslexia (from ancient Greek δυς dys , German 'bad' , 'difficult', 'miss'- [here = misunderstanding], λέξις léxis ' language', 'speech', 'style' [here = speech] bad / incorrect reproduction / To put it another way, one understands a so-called tool disorder in which the ability to read and understand words or texts is restricted despite normal vision and hearing . The term alexia (from ancient Greek α- a- 'not', 'un'-) denotes the complete inability to read.

description

While the term dyslexia or dyslexia is widespread in the English-speaking world and, as developmental dyslexia , also refers in particular to reading and spelling disorders ( dyslexia , ICD-10 F81.0 "circumscribed developmental disorders of school skills"), dyslexia in German is predominantly related to acquired skills Forms related to written language problems, e.g. B. can occur in brain damage due to accidents or tumors (ICD-10 R48.0).

Acquired dyslexia and developmental dyslexia

Acquired dyslexia occurs in children and adolescents who have inadequate synaptic interconnection of the individual language centers due to inadequate reading and writing training . Adolescents in the USA , but also in the European industrialized nations, are increasingly affected by this .

Developmental dyslexia, like acquired dyslexia and illiteracy, is one of the abnormalities in children's written language.

The possible characteristics of developmental dyslexia include: poor reading accuracy, slow reading speed, problems remembering read words, no holistic recording of highly familiar words, poor reading comprehension, omitting / replacing / adding words or parts of words and replacing words or parts of words with a semantically-like one Word. Difficulties in copying texts, illegible writing, insertions / deletions / substitutions of letters or syllables, incorrect segmentation of words and grammatical and punctuation errors can also arise.

In contrast to acquired dyslexia, the deficits of developmental dyslexia encounter an incompletely developed written language system. The orthographic lexicon is still insufficiently developed and the connections to the phonological lexicon and semantic system have not yet been established.

Dyslexia can also be triggered by brain damage (e.g. after a stroke or after a traumatic brain injury ). Other causes include cerebral or meningitis ( encephalitis , meningitis ), hypoxia (lack of oxygen), brain tumors, angiomas and epilepsy . Some of these people read words that are not there (for example, "cat" instead of "dog"), referred to as paralexia , others only read with difficulty spelling. The total inability to read is known as alexia. It is often associated with aphasia or agraphia. Dyslexia are treated by speech therapists , speech therapists and clinical linguists , among others .

to form

There are two different forms of central acquired dyslexia, surface dyslexia and deep dyslexia.

Deep dyslexia usually occurs in connection with global aphasia or Broca's aphasia . Those affected often manage to navigate to the lexicon , which is why both regular words and irregular words can usually be read without difficulty. Pseudo-words (freely invented words) can usually not be read. The perisylvic region and the basal ganglia are assumed to be the fault location.

Wernicke aphasia and amnestic aphasia in particular are considered to be the cause of surface dyslexia. Here, those affected usually have problems navigating the lexicon, which is why those affected often process the written language individually. This often creates difficulties when reading irregular words. The localization here is assumed to be in the posterior media branches and the Wernicke region.

Both forms can lead to null reactions, phonological paralexies and semantic paralexies.

Even within the classifications of the subtypes, there is a wide range of individual symptoms.

Neglect dyslexia

Neglect dyslexia is the reading disorder of patients who neglect one half of the room or body due to neglect syndrome caused by a brain lesion. The patient does not perceive or disregards the side of his surroundings or his own body opposite the brain lesion.

Neglect dyslexia is characterized by omissions of words, syllables or entire lines as well as substitutions (substitutions) of read words. While the omissions tend to occur in the contralesional half of the text, substitutions are less common overall, but about the same frequency in both halves of the text. Due to the numerous omissions (approx. 30–50% omissions in a text), these patients often miss the meaning of what has been read. As a result, they no longer enjoy reading and give up. Neglect dyslexia also shows up when reading numbers.

The most noticeable neglect symptoms usually resolve within a few weeks, but many affected patients remain significantly impaired in everyday functions (e.g. dressing, eating, transferring from bed to wheelchair, navigating with the wheelchair, reading and writing).

Diagnosis

The diagnosis of dyslexia consists of a norm-related and a model-oriented part. The norm-related diagnosis, which aims to differentiate average from below-average performance, is started. The following tasks are often used here: quiet / loud reading, word-picture assignment tasks and writing after dictation. In German-speaking countries, there are a number of written language tests available for which standards of various age and grade levels are available. The evaluation takes place on the basis of a determination of the correct or incorrect answers or a comparison with the standard data. This is followed by model-oriented diagnostics if either abnormalities are found in the norm-related diagnostics, or there is a suspicion that suspected abnormalities were not detected, or the therapist wants to check after completion of therapy whether there are structural changes in reading and / or writing to have.

When choosing a diagnostic method, attention should be paid to the current spelling rules, as this is relevant for the reading tests with regard to the performance.

Model-oriented diagnostics

By means of the model-oriented diagnostics, individual and differentiated planning of therapy goals can be carried out and successes or learning plateaus can be recognized, whereby the therapy success is checked. Previously available test batteries were developed exclusively for acquired dyslexia and dysgraphia and contain a detailed collection of tasks and stimuli to control the individual components of reading and writing. With the differentiated and statistically reliable model-oriented diagnostics, a content-rich error analysis can be achieved, but the implementation requires a high expenditure of time. The two-way model of reading and writing is used for diagnostics.

LEMO (Lexicon model-oriented) is a model-oriented diagnostic procedure and is used to examine written language. With this model, which is the only one that is also used to investigate child dyslexia and dysgraphia, individual routes and components of the two-way model can be controlled in a targeted manner. The evaluation in the diagnosis of child dyslexia poses a challenge due to the fact that the components are not yet fully developed due to age.

Reading and spelling weakness

In the conventional definition, there is a reading and spelling weakness when the patient's reading comprehension is well below the average of people with a comparable IQ . The practicability of this diagnosis has been questioned since the 1990s; a number of studies found no IQ-related differences between children with written language problems. It is therefore controversial whether developmental dyslexia is an objectively diagnosable disorder at all. In The Dyslexia Debate (2014) the authors propose that dyslexia is a “meaningless, pseudo-medical” diagnosis that primarily has a social function. Since no uniform definition of the diagnosis is generally accepted, the estimates of the prevalence also differ; Presumably, the diagnosis of "reading and spelling weakness" or developmental dyslexia combines a number of different etiologies; It is also possible that different written languages ​​or orthographies have different effects on the prevalence of dyslexia.

The particular accumulation of dyslexia in certain families suggests that this disorder is at least partially hereditary. Recent studies support this thesis : They show that a certain region on chromosome 6 is associated with a predisposition to dyslexia. A gene called DCDC2 is located on the said chromosome segment . In studies of 153 families in which dyslexia occurs, the same deletion (a certain chromosome mutation ) in the DCDC2 gene could always be detected. The exact function of the gene is still unclear, but there is experimental evidence that it plays an important role in the development of certain neurons in the brain . Schumacher and colleagues found further compelling evidence of the critical role of the DCDC2 gene in the development of dyslexia. They were able to detect certain genetic variations, so-called single nucleotide polymorphism (SNP), in this gene that make the carrier susceptible to the disorder. Different SNP markers seem to be responsible for the severity of the dyslexia.

According to the University of Haifa, one possible form of therapy is reading training under time pressure in order to synchronize the brain processes involved.

Trivia

In the American sitcom The Bill Cosby Show , the son of the "Theo" family suffers from dyslexia.

See also

Web links

Wiktionary: Dyslexia  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Sylvia Costard: Disturbances of the written language. Model-guided diagnostics and therapy . Ed .: Luise Springer, Dietlinde Schrey-Dern. Georg Thieme, Stuttgart 2007, ISBN 978-3-13-139641-9 , p. 75 .
  2. ^ Sylvia Costard: Disturbances of the written language. Model-guided diagnostics and therapy . Ed .: Luise Springer, Dietlinde Schrey-Dern. Georg Thieme, Stuttgart 2007, ISBN 978-3-13-139641-9 , p. 81 f .
  3. ^ Sylvia Costard: Disturbances of the written language. Model-guided diagnostics and therapy . Ed .: Luise Springer, Dietlinde Schrey-Dern. Georg Thieme, Stuttgart 2007, ISBN 978-3-13-139641-9 , p. 82 .
  4. ^ Sylvia Costard: Disturbances of the written language. Model-guided diagnostics and therapy . Ed .: Luise Springer, Dietlinde Schrey-Dern. Georg Thieme, Stuttgart 2007, ISBN 978-3-13-139641-9 , p. 75 .
  5. ^ Sylvia Costard: Disturbances of the written language. Model-guided diagnostics and therapy . Ed .: Luise Springer, Dietlinde Schrey-Dern. Thieme Verlag KG, Stuttgart 2007, ISBN 978-3-13-139641-9 , p. 76 .
  6. ^ Georg Kerkhoff, Christian Marquard: Acquired, visually caused reading disorders. Standardized diagnostics and therapy with READ. In: The neurologist . 12th edition. No. 80 . Springer, Berlin / Heidelberg December 2009, p. 1427-1428 .
  7. Thomas Brandt, Anouk Welfringer: Neglect treatment: new therapeutic approaches . In: The neurologist . 10th edition. No. 87 . Springer, Berlin / Heidelberg October 2016, p. 1068 .
  8. ^ Sylvia Costard: Disturbances of the written language. Model-guided diagnostics and therapy. Ed .: Luise Springer, Dietlinde Schrey-Dern. Thieme, Stuttgart 2007, p. 83 ff .
  9. ^ Sylvia Costard: Disturbances of the written language. Model-guided diagnostics and therapy. Ed .: Luise Springer, Dietlinde Schrey-Dern. 2nd Edition. Georg Thieme, Stuttgart 2007, ISBN 978-3-13-139641-9 , p. 93 .
  10. ^ Ria De Bleser, Jürgen Cholewa, Nicole Stadie, Sia Tabatabaie: LEMO. Lexicon model-oriented. Individual diagnosis of aphasia, dyslexia and dysgraphy. Urban & Fischer, Munich 2004, ISBN 978-3-437-47960-1 , pp. 22 .
  11. ^ Sylvia Costard: Disturbances of the written language. Model-oriented diagnostics and therapy. Ed .: Luise Springer, Dietlinde Schrey-Dern. 2nd Edition. Georg Thieme, Stuttgart 2007, ISBN 978-3-13-139641-9 , p. 94 .
  12. Linda S. Siegel: Perspectives on dyslexia . In: Pediatr Child Health , 2006 Nov; 11 (9), pp. 581-587, PMC 2528651 (free full text). "Until recently, the typical definition of dyslexia involved a discrepancy between an IQ score and a reading score. If the IQ score was found to be significantly higher than the reading score, then this discrepancy was used as an index of dyslexia. This definition has been discredited for a variety of reasons. […] A number of studies [] in different countries have found that there are no differences in children who have reading problems between those who have a discrepancy between IQ and reading scores and those who do not. ”Studies cited: JM Fletcher, DJ Francis, BP Rourke, SE Shaywitz, BA Shaywitz: The validity of discrepancy-based definitions of reading disabilities . In: J Learn Disabil. , 1992 Nov, 25 (9), pp. 555-561, 573. LS Siegel: An evaluation of the discrepancy definition of dyslexia . In: J Learn Disabil. 1992 Dec, 25 (10), pp. 618-629. FR Vellutino, DM Scanlon, GR Lyon: Differentiating between difficult-to-remediate and readily remediated poor readers: more evidence against the IQ-achievement discrepancy definition of reading disability . In: J Learn Disabil. , May-Jun 2000, 33 (3), pp. 223-238.
  13. ^ Julian G. Elliott, Elena L. Grigorenko: The Dyslexia Debate . In: Cambridge Studies in Cognitive and Perceptual Development, 2014, ISBN 978-0-521-13587-0 ( reviews ).
  14. Kristin Leutwyler: Scientists Explain Rates of Dyslexia . In: Scientific American , March 16, 2001.
  15. ^ Haiying Meng et al .: DCDC2 is associated with reading disability and modulates neuronal development in the brain . In: PNAS . tape 102 , no. 47 , 2005, p. 17053-17058 ( online [accessed April 7, 2014]). Online ( Memento of the original from December 4, 2007 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.pnas.org
  16. J. Schumacher, H. Anthoni, F. Dadouhet al .: Strong genetic evidence of DCDC2 as a susceptibility gene for dyslexia. Archived from the original on May 15, 2013. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF) In: The American Journal of Human Genetics . 78, No. 1, January 2006, pp. 52-62. doi : 10.1086 / 498992 . PMID 16385449 . @1@ 2Template: Webachiv / IABot / download.cell.com
  17. Read faster = read better. In: science.ORF.at. Retrieved March 26, 2020 .
  18. Zvia Breznitz et al .: Enhanced reading by training with imposed time constraint in typical and dyslexic adults . In: Nature Communications . tape 4 , no. 2 , February 12, 2013, doi : 10.1038 / ncomms2488 .