Dyslexia: Types, Symptoms, Causes, Treatments And Consequences

The  Dyslexia is a learning disorder that is characterized by difficulty reading all kinds of texts even though the person holds normal intelligence. It is the most common reading disorder that exists, and affects a large number of people of all ages and conditions to a greater or lesser extent.

Dyslexia can cause a wide variety of different problems. Some of the most common are the difficulty to spell, the decrease of the maximum speed at which the person can read, problems to write words correctly, errors when pronouncing aloud what is being read, and difficulties in reading comprehension.

People with dyslexia suffer from these problems with reading since they were children, the first symptoms generally appearing in the first years of school age. Individuals who were able to read normally at first but later lost the ability suffer from a related but distinct disorder known as alexia.

The exact causes of dyslexia are not known. However, it is believed that this learning disorder could be related to problems in the area of ​​language processing in the brain. The causes of dyslexia are generally considered to be both genetic and environmental.


Dyslexia is estimated to affect approximately 20% of the adult population. However, not all people with this disorder have the same symptoms. Next we will see some of the most common variants of this pathology.

Phonological dyslexia

One of the most common forms of dyslexia is that which causes difficulty in recognizing the individual sounds of each letter and combining them to form whole words. People with this variant of the disorder may have trouble spelling or breaking a word into its component syllables.

At the same time, people with phonological dyslexia also have difficulties when it comes to representing sounds graphically, because they are not able to associate each letter with the phoneme that corresponds to it. It is precisely from this problem that their inability to read correctly comes.

Superficial dyslexia

The main trait of people who suffer from superficial or direct dyslexia is the difficulty to read words that are written differently from the way they are pronounced. This variant is believed to be more related to the visual pathway of the brain, rather than the auditory one.

Despite the fact that there are not many words in Spanish that are spelled differently than how they are pronounced, people with this difficulty can also have problems in our language. For example, they may have trouble recognizing homophone words, or with arbitrary spelling.

However, superficial dyslexia causes much more serious problems for people who have to read in a language in which the writing is different from the pronunciation, such as English or French.

Rapid self-recognition dyslexia

Another of the most common types of dyslexia is the one that causes the person to take more time than normal to recognize the written form of letters or numbers. Generally, it is not considered as serious as the rest of the alternative forms of this pathology.

Still, rapid self-recognition dyslexia can cause serious difficulties in some settings, especially those where the person is required to write or read at high speed.

Mixed or profound dyslexia

Mixed dyslexia is generally considered the most serious form of this condition. When it appears, the two ways of recognizing words are damaged: auditory and visual. Due to this, errors of all kinds can appear in reading and writing.

People with mixed dyslexia have very serious difficulties understanding the meaning of a written word. In addition, they present both semantic errors, such as difficulties in recognizing pseudowords and understanding abstract words, function words (such as prepositions and determiners) and conjugated verbs.


The symptoms of dyslexia vary tremendously between individuals, both in the intensity with which they occur and in the areas they affect. Depending on the type of dyslexia we are talking about, we can find tremendously varied symptoms.

However, what is quite common among all people who suffer from dyslexia are the consequences that this pathology causes. Next we will see what are the most common signs that may indicate that an individual may have a difficulty of this type to read.

Symptoms in preschool-age children

Dyslexia is usually detected once a person has begun their primary education, at the time when the teaching of reading and writing begins. However, in some cases it is possible to discover this pathology before this moment, even before the child enters school.

Before the ability to read and write is acquired, the signs that may indicate the future presence of dyslexia have to do with language. For example, a child may have developed a less extensive vocabulary than other individuals her age. At the same time, it is common for pronunciation errors to occur in complex words.

On the other hand, these children often have difficulties expressing themselves correctly in a spoken way. This may mean, for example, that they frequently forget the word they want to use, or that they put together phrases that are not related to each other.

Finally, preschool children with dyslexia often show little interest and difficulty understanding rhymes, nursery rhymes, and word games. They also tend to show very low interest in learning the letters of the alphabet. However, these indicators do not necessarily have to mean that the child will have this problem.

Symptoms in school-age children

Symptoms of dyslexia often become really obvious for the first time when the child enters school and has to start learning to read and write. Between the ages of 5 and 12, it is possible to detect this disorder in most cases.

The first difficulty that usually appears is learning the name and sound of each letter. Because of this, children with dyslexia have trouble spelling words correctly, as well as making many mistakes in writing.

Some of the most common mistakes are the representation of figures in a reverse way (such as writing a “b” instead of a “d”), or changing the order of the letters in a word. Furthermore, their handwriting is often very bad, and they have difficulty writing at high speeds.

At the reading level, children of this age also do it much slower than their peers. At times, they can express that they see the letters as if they were blurred or moved, although it has been proven that when this happens trying to improve vision with glasses is useless.

Symptoms in adolescents and adults

The symptoms that we have seen so far tend to remain in adolescence and adulthood as well. However, due to the importance of reading and writing in these stages of life, there are also other indirect signs that could help diagnose dyslexia if it has not been done by that time.

The most important symptom in adulthood is the difficulty to produce coherent and organized texts, even with extensive knowledge on a topic. Because of this, people with dyslexia often have trouble writing reports, papers, or essays.

These difficulties can bring serious problems both during student life (such as causing the notes that are taken to be of low quality) and at work. The person with dyslexia will generally try to avoid reading and writing as much as possible, which can have very negative consequences.


Since dyslexia was first identified in 1881, researchers have tried to find the cause of this disorder. Although it has not yet been discovered why some people have reading problems of this type, several factors have been found that seem to influence the appearance of this pathology.

In general, it is possible to divide the causes of dyslexia into three types: neuroanatomic, genetic, and environmental.

Neuroanatomic causes

Using modern neuroimaging techniques, such as functional magnetic resonance imaging or positron emission tomography, it has been discovered that people with dyslexia present both anatomical and functional differences at the brain level with those who do not have this disorder.

However, the abnormalities that individuals with dyslexia present at the brain level are not always the same. In some cases, for example, people with this disorder may have less activation in the parts of the left lobe associated with reading, such as the inferior frontal gyrus.

Others, however, have alterations more related to the cerebellum . In these cases, speech fluency problems are more likely to appear, since this brain organ is related to motor control and automation of certain tasks.

However, as is often the case in neuroscience studies, today it is impossible to decide whether the brain alterations of people with dyslexia were already present at birth, or if on the contrary they appear due to environmental factors. Therefore, we do not know if they are a cause or a consequence of the problem.

Genetic causes

Investigations of the possible connection between genetic factors and dyslexia have their origin in studies carried out through autopsies of patients suffering from this problem. In most of these cases, abnormalities have been found that suggest that genes may play a fundamental role in the appearance of the pathology.

For example, many of the patients examined after their death had microscopic malformations in the cerebral cortex, known as ectopias. In other cases, some vascular micromalformations were also present, in addition to micro-gyrations (parts of the brain less dense than usual).

All of these studies seem to suggest that genetics play a fairly important role in the development of dyslexia, although it cannot be said that it is the only cause. These malformations are believed to occur before or during the sixth month of fetal development, when the brain changes the most.

At the genetic level, some genes have been linked to dyslexia, including DCDC2, KIAA0319 and DYX1C1.

Influence of environmental factors

Numerous scientists have tried to discover the weight of the environment against genetics in the appearance of dyslexia. The main mechanism for discovering this ratio is twin studies. These indicate that, although genes appear to play a larger role, the environment can prevent or lessen symptoms.

In addition to this, today we know that capacities such as memory and learning can only be developed to their maximum potential if there is a suitable environment. Therefore, it is believed that something similar could happen with reading. The relationship between the environment and the expression of genes is known as epigenetics.


Dyslexia is a type of disorder that will occur throughout the lives of people who suffer from it. With efficient intervention, in many of the cases develop optimal learning to read and write (International Dyslexia Association, 2016).

Early identification and early treatment is essential to achieve control of deficits and successful adaptation to different levels academics.

In many cases, the intervention of a specialized therapist who uses different multisensory strategies will be required to work with the reading difficulties. It is important that the intervention is carried out through a systematic method that involves several senses (International Dyslexia Association, 2016).

Students with dyslexia often require repeated feedback and a high amount of practice to develop correctly and effective word recognition skills (International Dyslexia Association, 2016).

Academic modifications are frequently applied to facilitate curricular success. Students with dyslexia tend to take longer to complete homework or note-taking aids (International Dyslexia Association, 2016).

Can the symptoms of dyslexia be controlled?

In principle, there is no treatment that will eliminate the symptoms of dyslexia completely. However, if compensatory strategies are used from a very early age, many of the children with this pathology can learn to read more or less normally.

The focus of these treatments is usually to teach children to correctly associate each letter with the sound it represents. In this way, many of the difficulties caused by dyslexia disappear or diminish significantly.

On the other hand, in cases where dyslexia is very severe, the affected person can greatly benefit from other support systems. Among the most common are the use of calligraphic fonts specially designed for dyslexics, or the use of automatic reading and voice dictation technologies.

Using these types of strategies, even people with dyslexia who are unable to learn to read and write at an acceptable level can lead almost normal lives.


The impact of specific reading disorder is different for each person and depends largely on the severity and the interventions specific that are being carried out.

The main problems that people with dyslexia have are difficulty recognizing words, reading fluency and in some cases difficulty in spelling and writing (International Dyslexia Association, 2016).

In many cases, they can also present expressive language problems even though they were exposed to good language models in their familiar contexts and schoolchildren before. Difficulties may appear to express themselves clearly or to understand the totality of the messages emitted by other people (International Dyslexia Association, 2016).

Although on various occasions it is difficult to recognize or identify some of these language problems, they can trigger consequences important at school, work or in social relationships.

In addition, it can also affect the personal image; many students come to feel less capable, underestimating both their abilities and potential abilities (International Dyslexia Association, 2016).


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