Dyslexia is a partial disorder of reading skills caused by insufficient formation (or decay) of mental functions involved in the implementation of the reading process. The main signs of dyslexia are persistence, typicality and repetition of errors when reading (mixing and replacing sounds, letter-by-letter reading, distortion of the syllable structure of a word, grammatisms, impaired comprehension of what has been read). Diagnosis of dyslexia involves assessing the level of formation of oral speech, writing, reading, non-speech functions. To overcome dyslexia, it is necessary to develop the disturbed aspects of oral speech (sound pronunciation, phonemic processes, vocabulary, grammatical structure, coherent speech) and non-speech processes. Dyslexia symptoms reasons and classification
Dyslexia – specific difficulties in mastering reading skills, due to the underdevelopment of HMFs involved in the implementation of the reading process. The prevalence of dyslexia among children with normal intelligence is 4.8%. Children with severe speech impairments and CRD suffer from dyslexia in 20-50% of cases. The ratio of the incidence of dyslexia in boys and girls is 4.5: 1.
According to the severity of the violation of the reading process in modern speech therapy, it is customary to distinguish between dyslexia (partial disorder of a skill) and alexia (complete inability to master a skill or its loss). Dyslexia ( alexia ) can be observed in isolation, but more often it accompanies another violation of written speech – dysgraphia .
Most researchers studying the problem of dyslexia in children note a history of exposure to pathological biological factors that cause minimal cerebral dysfunction :
- Hypoxic brain damage is noted with improper implantation of the ovum, anemia and heart disease in the mother, congenital heart defects in the fetus, fetoplacental insufficiency , anomalies in the development of the umbilical cord , prolonged labor, premature detachment of the placenta , asphyxia in childbirth , etc.
- Toxic damage to the central nervous system is observed with alcohol and drug intoxication, hemolytic disease of the fetus , nuclear jaundice of newborns .
- Infectious damage to the brain of a child in the prenatal period can cause diseases of pregnant rubella , measles , herpes , chickenpox , flu, etc.
- Mechanical damage is associated with fruiting manipulations, a narrow pelvis of a woman in labor, prolonged labor, intracranial hemorrhage . Dyslexia symptoms reasons and classification
In the postnatal period, a delay in the maturation and functioning of the structures of the cerebral cortex, leading to dyslexia, can be initiated by:
- traumatic brain injury ;
- a chain of childhood infections (rubella, measles, chickenpox, poliomyelitis , etc.);
- debilitating diseases.
Dyslexia (alexia) with alalia , dysarthria , aphasia is associated with organic damage to certain areas of the brain. In foreign literature, the theory of a hereditary predisposition to writing and reading disorders – dysgraphia and dyslexia in people with a right-brain type of thinking – is widespread. Some authors point to the connection between dyslexia and dysgraphia and overt and latent left-handedness.
Among the social factors of dyslexia, the greatest importance is played by the deficit of verbal communication, the syndrome of ” hospitalism “, pedagogical neglect , an unfavorable speech environment, bilingualism , early start of literacy and a high rate of learning. The leading prerequisite for dyslexia in children is the lack of formation of oral speech – FFN or OHR .
In the control and implementation of reading, as a psychophysiological process, the visual, speech-motor and speech-auditory analyzers are involved. The reading process includes the following stages:
- visual perception, recognition and discrimination of letters;
- correlating them with the corresponding sounds;
- fusion of sounds into syllables; combining syllables into a word, and words into a sentence;
- reading comprehension, comprehension.
Disruption of the sequence and unity of these processes is the essence of dyslexia from the point of view of psycholinguistics.
In the psychological aspect, the mechanism of dyslexia is considered from the point of view of a partial delay in the development of mental functions that normally provide the reading process. In dyslexia, there is a lack of formation of visual gnosis, spatial orientations, mnestic processes, phonemic perception, lexical and grammatical structure of speech, visual-motor or auditory-motor coordination, as well as attention and emotional-volitional sphere. Dyslexia symptoms reasons and classification
According to the leading manifestations, they distinguish between literal (associated with difficulties in assimilating individual letters) and verbal (associated with difficulties in reading words) dyslexia.
In accordance with the impaired mechanisms, it is customary to distinguish the following forms of reading impairment:
- Phonemic dyslexia (due to underdevelopment of phonemic perception, analysis and synthesis)
- Semantic dyslexia (due to the lack of formation of syllabic synthesis, poverty of the dictionary, misunderstanding of syntactic connections in the structure of the sentence).
- Agrammatic dyslexia (due to underdevelopment of the grammatical structure of speech, morphological and functional generalizations)
- Mnestic dyslexia (due to impaired speech memory, difficulty in matching letter and sound)
- Optical dyslexia (due to the lack of formation of visual-spatial representations)
- Tactile dyslexia (due to blurred tactile perception in the visually impaired).
Thus, phonemic, semantic and agrammatic dyslexias are associated with the unformed speech functions, and mnestic, optical and tactile dyslexia – with the unformed mental functions.
In oral speech, children with dyslexia have defects in sound pronunciation, poor vocabulary , inaccurate understanding and use of words. The speech of children with dyslexia is characterized by incorrect grammatical design, the absence of detailed sentences, and incoherence.
In case of phonemic dyslexia, substitutions and mixing among themselves of sounds that are similar in articulatory or acoustic characteristics (voiced-deaf, whistling-hissing, etc.) come to the fore . In other cases, letter-by-letter reading, distortions of the sound-syllable structure of the word (additions, omissions, permutations of sounds and syllables) are noted. Dyslexia symptoms reasons and classification
Semantic dyslexia is also called “mechanical reading”, because with this form, comprehension of the read word, phrase, text is impaired with the correct reading technique. Violation of reading comprehension can occur in both syllable and synthetic reading.
In the case of agrammatic dyslexia, there is an incorrect reading of the case endings of nouns and adjectives, forms and tenses of verbs, a violation of the agreement of parts of speech in number, gender and case, etc. Agrammatisms when reading correspond to those in oral speech and writing.
With mnestic dyslexia, the association between the visual form of the letter and its pronunciation and acoustic image is disrupted. That is, the child does not memorize letters, which is manifested in their mixing and substitutions when reading. When the examination verbal memory in a child with dyslexia is detected mnestical can not play back a series of 3-5 sounds or words, violation of their order, reducing the amount of elision.
Optical dyslexia is manifested by mixing and replacing letters that are graphically similar and differ only in individual elements or spatial arrangement (b-d, z-c, l-d). With optical dyslexia, there may be slippage from one line to another while reading. Optical dyslexia also includes cases of mirror reading performed from right to left.
Tactile dyslexia is common for blind people. It is manifested by mixing tactilely similar letters (close in number or location of dots) when reading Braille. In the process of reading, a child with tactile dyslexia may also experience slipping off lines, missing letters and words, distorting the meaning of what has been read, chaotic movements of the fingers, etc. Dyslexia symptoms reasons and classification
Speech therapy examination consists of characteristics of the level of formation of oral speech, writing, reading, non-speech processes. At the preliminary stage, the speech therapist studies the history of the child’s life and development, the peculiarities of the formation of speech, the state of the articulatory apparatus, speech and manual motor skills; finds out the student’s progress in the Russian language.
- Diagnostics of oral speech . Includes an assessment of sound pronunciation, phonemic development, the formation of the syllable structure of the word, lexical and grammatical means of the language, coherent speech.
- Diagnostics of written speech . Assumes the completion of tasks for copying texts, writing by ear, independent writing. When examining reading aloud and silently, the pace and correctness of reading, the way of reading, the comprehension of the text, and specific mistakes are assessed.
- Neuropsychological diagnostics . An important component of a speech therapy examination for dyslexia is to clarify the level of formation of visual gnosis, mnezis, analysis and synthesis; optical-spatial orientations.
According to the indications, the diagnostic examination of speech is supplemented by a medical diagnostic unit, which may include a consultation with a pediatric neurologist with the performance of EEG , EchoEG ; consultation of a pediatric ophthalmologist with ophthalmological tests .
The traditional system of speech therapy classes to correct dyslexia involves differentiated work on all impaired aspects of oral speech and non-speech processes.
- In case of phonemic dyslexia, the main attention is paid to the correction of defects in sound pronunciation, the development of full-fledged phonemic processes, the formation of ideas about the sound-letter and sound-syllable composition of the word.
- The presence of semantic dyslexia requires the development of syllabic synthesis, clarification and enrichment of the vocabulary, the child’s assimilation of the grammatical norms of the language.
- In the case of agrammatic dyslexia, it is necessary to form the child’s grammatical systems of word formation and inflection.
- Mnestic dyslexia requires the development of auditory speech and speech memory.
- With optical dyslexia, work is underway to develop visual-spatial representations, visual analysis and synthesis.
- With tactile dyslexia, the task of correction is the differentiation of tactilely perceived objects and schemes, the development of spatial representations.
A non-standard approach to the correction of dyslexia is offered by the method of Ronald D. Davis, which involves giving printed words and symbols a mental figurative expression, with the help of which gaps in perception are eliminated. Dyslexia symptoms reasons and classification