This learning disorder affects many boys and girls. We explain what it consists of.
Dyslexia is a learning disorder that leads to reading difficulties , such as letter confusion, interchange, omissions, etc. It affects many girls and boys of school age, and is usually detected at school, from the age of 7.
In this article we will know its most important characteristics, symptoms, causes, types and ways that we can use to read. In addition, we will mention some tests that are used to detect dyslexia.
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Dyslexia: what is it?
Dyslexia is a learning disorder that affects many school-age girls and boys . In it, reading performance is below the expected performance, taking into account the child’s age, as well as other factors (IQ and schooling). Intelligence , however, is within normal parameters.
That is, the affectation occurs only in reading. The difficulties of the person with dyslexia interfere with their academic performance, or even in activities that they carry out in their daily life.
On the other hand, the disorder may appear in people with some type of sensory deficit; however, to be able to diagnose dyslexia it is necessary that such difficulties exceed those usual for the person.
It is recommended not to diagnose dyslexia before the age of 7, since these are very early ages where children are still growing, learning and developing their abilities.
diagnostic manuals
In the DSM-IV-TR (2002) (Diagnostic Manual of Mental Disorders) dyslexia was diagnosed as “reading disorder”. In the next edition, however (in the DSM-5) it is diagnosed as a specific learning disorder .
This new (unique) category includes all possible disorders related to learning (dyslexia, dyscalculia, writing disorders, etc.).
Symptoms
The criteria to diagnose a specific learning disorder in the DSM-5 (and therefore, a dyslexia) are four.
1. Learning difficulties
In this case, the difficulties cover the area of reading ; the dyslexic boy or girl makes mistakes while reading, confuses some letters with others (for example “b” with “d”), does not recognize some words, etc. All this will depend on the type of dyslexia, as we will see later.
Thus, reading in dyslexia becomes imprecise, slow or with inadequate intonation. All this can lead to difficulties in understanding what is read.
2. Performance interference
Reading difficulties interfere with the student’s academic performance . This can be evidenced by standardized tests, administered individually.
A significant decrease in performance is considered when the result is 2 standard deviations below the mean (according to the age of the student). In the case of boys and girls over 17 years of age, it is detected by a documented history of the student’s own performance.
3. Start at school age
In dyslexia, as in other specific learning disorders, the difficulties begin at school age; however, these may not appear until the academic or environmental demands exceed the capabilities of the student .
4. Exclusion of other disorders
Finally, in order to diagnose dyslexia or another specific learning disorder, the symptoms must not be explained by another disorder or disability , such as an intellectual disability (ID), a visual or hearing impairment, a mental or neurological disorder, lack of language proficiency, inadequate educational instruction, or some psychosocial adversity.
types of dyslexia
There are three types of dyslexia, depending on the lexical pathway that is affected to read. Let’s see what each one consists of.
1. Surface dyslexia
In surface dyslexia (also called visual-perceptual dyslexia), difficulties appear in reading irregular words (ie, rare words). Here the lexical, direct or visual way of reading is affected.
From this path, the graphic representation of words is related to their meaning. That is, people who read in this way rely on the perceptual-visual aspects of the reading process (that is, on the letters themselves).
2. Phonological dyslexia
Phonological dyslexia , also called auditory-linguistic dyslexia, is characterized by an alteration of the non-lexical pathway of reading (indirect or phonic pathway). This type of path receives other names, such as phonological or sequential path; people who use it when reading, access the meaning of words through sounds.
That is, graphic signs are transformed into sounds through the grapheme-phoneme conversion system. Thus, people with phonological dyslexia have difficulty reading pseudowords (that is, invented words that do not exist).
3. Deep dyslexia
Finally, deep dyslexia is the most serious of all. In it, the indirect or phonological pathway is totally affected, as well as the lexical or visual pathway partially. Thus, difficulties appear to read all the words, whatever their type; irregular, pseudowords and regular. Also called mixed dyslexia.
Other alterations in dyslexia
The neuropsychological perspective proposes the previous classification of the types of dyslexia , but also adds a series of alterations that may appear comorbid or consequent to dyslexia. Let’s see what they are in each of them.
1. Perceptual-visual dyslexia
It corresponds to superficial dyslexia. According to the neuropsychological perspective, this type of dyslexia usually appears at 7-8 years of age. The deficits that it entails affect perceptual-visual skills, psychomotricity and immediate memory.
The person with this type of dyslexia will be confused with the letters, and will also have difficulties in understanding. The writing, in addition, is also altered (for example, it is written with inversions, or in a mirror).
2. Auditory-linguistic dyslexia
This corresponds to phonological dyslexia, and usually appears a little later, in children between 9 and 12 years old. The alterations in this case focus on three areas: auditory discrimination, immediate auditory memory and other psycholinguistic abilities.
Here the child confuses similar-sounding words. He also has comprehension problems, omission errors (he “skips” words when reading) and changes in writing, with frequent syntactic errors.
3. Mixed dyslexia
The last dyslexia, mixed or deep dyslexia, combines the problems of the two previous types. In addition, it entails a null understanding of what is read.
Evaluation
The most widely used tests to assess reading and, by extension, dyslexia are: the TALE and the EMLE-TALE (2000), based on a behavioral model and aimed at children between 1st and 4th grade of Primary Education; the PROLEC-R, based on a cognitive model, for children between 1st and 6th grade of Primary Education; the PROESC (more oriented to writing), for children from 3rd year of Primary Education to 4th year of ESO, and finally the EDIL-1 and the ECL.
Causes
The causes of dyslexia vary according to the type of theoretical model.
1. Biological model
This model bets on a genetic influence , and mentions some brain alterations present in dyslexia, such as asymmetry of the temporal plane and anomalies in the development of the cerebral cortex and the medial and lateral geniculate nucleus.
2. Neuropsychological model
The neuropsychological model proposes a maturational delay in the left hemisphere (the language hemisphere) in people with dyslexia. It establishes that in dyslexia, at 6-7 years of age, a delay in sensorimotor and visuoperceptive functions appears.
On the other hand, at 9-12 years old, he explains that the delay occurs in verbal and conceptual functions. In short, this model is committed to a dysfunction that causes a series of neuropsychological deficits that influence learning.
3. Cognitive model
The cognitive model of dyslexia refers to the concept of “logogen”, proposed by Morton. According to this author, the logogen includes the entire mental lexicon, which would be altered in people with dyslexia.
In the cognitive model we also find Uta Frith, who developed a three-phase model of reading acquisition: the logographic, alphabetic and orthographic phase. In dyslexic subjects, difficulties would appear in any of the three phases (or in more than one).
4. Behavioral model
This model refers to learned behaviors to explain dyslexia (or rather, poorly learned behaviors) . Toro & cols., behavioral authors, establish three sequential phases in the reading process: decoding (1st year of Primary Education), fluency and intonation (2nd year of Primary Education) and comprehension (3rd year of Primary Education).
In dyslexia there would be difficulties in these three phases (or in any of them).
5. Integrative model
The integrative model was proposed by Uta Frith as well, and refers to a multifactorial origin of dyslexia , including biological, behavioral, cognitive, and environmental factors.
Bibliographic references
- APA (2014). DSM-5. Diagnostic and Statistical Manual of Mental Disorders. Madrid. Pan American.
- Horse, V., Simon, M.A. (2002). Child and adolescent clinical psychology manual. Specific disorders. Pyramid: Madrid.
- Cuetos, F. (2010). Psychology of reading. Learning to read. Chapter VIII. WK Education: 169-194.
- Puente, A., Jiménez, V. and Ardila, A. (2009). Brain abnormalities in dyslexic subjects. Latin American Journal of Psychology, 41(1): 27-45.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.