Dyslexia

Description:

There is no standard definition of a dyslexia now. One of opredelniya is offered the International association of a dyslexia (IDA):
The dyslexia is the type of specific disturbance of training having the neurologic nature. It is characterized by inability quickly and correctly to recognize words, to carry out decoding, to master skills of spelling. These difficulties are connected with inferiority of phonologic components of language. They exist, despite safety of other cognitive abilities and full-fledged conditions of training. For the second time there are disturbances of understanding of the text, deficit of reader's experience and the dictionary.

This definition is accepted the board of directors of IDA on November 12, 2002.

It is accepted to distinguish the dyslexia and difficulties of mastering reading caused by other reasons, such as mental retardation, a vision disorder and hearing. They are called still nonspecific, or secondary disturbances of reading. The dyslexia is distinguished from them by firmness and selectivity of disturbances.

Historic facts. The term "dyslexia" is entered by the ophthalmologist Rudolf Berlin in 1887. He used this term concerning the boy who had problems in training in reading and the letter, despite the lack of any intellectual and physical deviations.

In 1896 the therapist V. Pringl Morgan published in "The British medical magazine" (British Medical Journal) article under the name "Inborn Verbal Blindness" with the description of the specific psychological frustration influencing ability to learnability to reading. In the article he referred to a clinical case of disturbance of reading at the teenager of 14 years, despite the normal level of mental abilities.

In 1925 neuropathologist Samyuel T. Orton (Samuel T. Orton) started studying of a phenomenon of a dyslexia and assumed existence of the syndrome which is not connected with injury of the brain reducing abilities to reading and the letter. Orton noted lack of communication between problems with sight and disturbance of reading. According to Orton's theory, this state could be caused by mezhpolusharny asymmetry of a brain. Orton considered that at this disease the right and left cerebral hemispheres as if "change" roles - i.e. each of them  does work  for another. However later it changed the hypothesis and gave other definition to a dyslexia – "the mixed dominance of hemispheres".  The theory was disputed by many scientists of that time considering that the various problems arising in the course of visual perception of information are the main reason for a disease.

In 1949 Clement Laune studied anomaly at the adults who had a dyslexia since the childhood. The research showed a possibility of such people to read texts from left to right and from right to left with an identical speed (at 10% the speed of reading was from right to left higher). Results indicated changes of a field of vision which quoted to perception as a nabotra of separate letters, but not as a whole.

In the 1970th theories that the dyslexia is result of defects of phonologic or metaphonologic development moved forward. In recent years this theory enjoys in the West the greatest popularity.

Dyslexia symptoms:

Dyslexia — frustration, difficult for diagnosis. There are many factors which need to be taken into account to specialists when carrying out diagnosis of this disease. During testing the level of how the child reads is defined and is compared to how children of his age read. It is carried out by means of cognitive testing. All indicators of reading are fixed by the doctor, during the research marks become where reading is broken. During various tests hearing and ability of the child to reproduction of the speech is checked. Also is defined how the child is better perceives information: orally (at a conversation) or taktilno (when something does by the hands). During the research the conclusion also becomes, all three components of touch system how well work.

The child should not feel that something occurs not so at execution of the test. He has to feel comfortable and surely therefore some researches can be conducted in the form of a game. Before conducting testing the child needs to sleep and to have breakfast well. If testing is held at school, then before performance of a research the teacher needs to talk to the child, to explain to him who will come and why. If testing is held not at school, then parents need to give support to the child that that felt comfortable. Parents are not recommended to be present when testing the child by specialists.

Types of a dyslexia:

    1. A phonemic dyslexia - this type of disturbance of reading is most widespread among younger school students.  The phonemic dyslexia is connected with an underdevelopment of functions of phonemic system. One phoneme differs from another in a set of smyslorazlichitelny signs (N-r,  hardness - softness; sonority - dullness; way and place of education, etc.). Change of one of phonemes in the word (braids - goats; the house - volume - a lump) or sequence change (a linden - a saw) leads to change of sense.
    Most often the child with this form of a dyslexia mixes aurally the sounds differing in one smyslorazlichitelny sign (c - with; with-sh;).
    It is noted also:
- letter by letter reading;
- distortion of sound syllabic structure of the word (admissions of letters, inserts, shifts of sounds, syllables.)

    2. Semantic dyslexia (so-called mechanical reading). It is shown in disturbance of understanding of the read words, offers, the text at technically correct reading. Disturbance of the understanding read is caused by two facts: difficulties of sound syllabic synthesis and an illegibility of ideas of syntactic links in the offer (when words in the course of reading  are perceived separately, out of communication from in other words offer).

    3. Agrammatichesky dyslexia. It is most often observed at children with a system underdevelopment of the speech. At this form of a dyslexia it is observed:
- change of declensional endings and number of nouns ("at companions");
- the wrong approval in a sort, number and a case of a noun and an adjective ("interesting the fairy tale");
- change of the terminations of verbs of the 3rd person of past tense.

    4. Optical dyslexia. It is shown in difficulties of assimilation and in mixing of similar graphic letters. The letters differing in only one element mix up (V-Z; M); the letters consisting of identical elements, but variously located in space (T-@; R-£; P-N-I).

    5. Mnestichesky dyslexia. This form of a dyslexia is shown in difficulty of assimilation of letters. The child does not know what letter corresponds to this or that sound.

Dyslexia reasons:

Numerous researches by means of modern methods of neurovisualization (MRT, PET, etc.) proved that dyslexias are the cornerstone the neurobiological reasons. Certain zones of a brain, namely a back part of the left average temporal crinkle, at such people are functionally less active, than at investigated without reading disturbances. The structure of brain fabric has at persons with a difference dyslexia from norm too. Zones of the lowered density in a back part of an average temporal crinkle are also found in them at the left.

As it became clear, the dyslexia is a syndrome with hereditary conditionality. In 1917 the English researcher J. Hinshelvud found repeated cases of a dyslexia in the child's relatives with a dyslexia. Cases of repeated diagnosis of a dyslexia in families at other relatives were observed also at the subsequent researches. In 1950 B. Hallgren conducted the first basic research of hereditary cases of a dyslexia, studying genealogy of such persons. The strongest evidences of the hereditary nature of a dyslexia are obtained in twin researches. As a result of the conducted researches it is proved that at unioval twins the frequency of coincidence (concordance) of existence of a dyslexia considerably exceeds the same indicator at nonidentical twins (respectively, 73% and 47%) the Indicator of heritability of a dyslexia makes 40-70%. In molecular and genetic researches it was succeeded to find the genes responsible for developing of a dyslexia. They are located in chromosomes № 1, 6 and 15.

Treatment of the Dyslexia:

Correction of a dysgraphia and dyslexia is most successful at an early stage of its development. Prevention – even more effective measure allowing to prevent these  frustration.

Most of children cannot make the diagnosis up to 8-9 years. If there was an opportunity to diagnose this disease at earlier stage – to them the additional help still could be provided before children begin to experience difficulties in study. It means that parents need to work together with school to be confident that children receive the necessary help.
It is necessary to hold early trainings with phonemes which help dyslexics to read better. It is the specific type of language training directed to sound structure of the word, but not just to the general skills of reading. There is a software the sounding of words allowing to slow down or stretch, helping children to practice to display words on phonemes.
Besides, dyslexics can have problems with long or new words. It is difficult for them to master mechanical storing as they need context keys to understand a word meaning. Therefore, it is much more difficult for such people to pass test when training and many schools entered such formats of tests which allow to define fairly their knowledge, providing questions and answers with a context. The example of such tests is an essay or oral examination.
Dyslexics often feel very tired as reading takes away from them much more forces than from healthy people. Many schools provide them more time for performance of examinations for receiving fair assessment of studied.