Some brain injuries can cause different types of language disorders.
Aphasias are language disorders due to lesions in the brain , which produce abnormal functioning in this part of the nervous system.
But the human brain is a very complex set of organs, and that’s why different types of injuries will give rise to different symptoms. For this reason, neurologists, psychologists and psychiatrists distinguish between different types of aphasia, each of which is associated with a different affectation in the use of language and a damaged brain region.
In this article we will see a summary of the existing types of aphasia , explaining what its symptoms and causes are.
On the other hand, it must be taken into account that the lesions that produce these alterations can only take place in the hemisphere in which most of the mental processes associated with language occur, and which is normally the left hemisphere.
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The 7 types of aphasia
When we think about our ability to use language, it is possible that we understand this psychological ability as a whole, something that cannot be divided into different mental processes.
However, the study of clinical cases of people with different types of aphasia shows us that where there seems to be only one mental faculty called “language”, there are actually several processes that are coordinated with each other to allow us to function well in the emission and understanding. messages through symbols and signs, both in spoken and written language.
As normally in healthy people these processes are always expressed together, their existence as something individual and separate from the rest goes unnoticed, but the differences between them are evidenced in certain patients with brain injuries.
So let’s see what these types of aphasia are, how they differ , and what symptoms they manifest.
1. Wernicke’s aphasia
In Wernicke’s aphasia, also called receptive aphasia or comprehension aphasia , the area of the brain that is damaged is the back of the superior temporal gyrus, or Wernicke’s area .
It is an area of the cerebral cortex located in the part of the temporal lobe closest to the parietal lobe, and is associated with language comprehension . In addition, it owes its name to the fact that it was discovered as such by the neurologist Carl Wernicke.
On the other hand, other parts of the brain that are very close to Wernicke’s area and are often also damaged in patients with this type of aphasia are the supramarginal gyrus and the angular gyrus.
The symptoms of Wernicke’s aphasia have to do above all with the comprehension of language, whether oral or written, and also with serious problems when saying sentences with meaning.
Both the speech and the writing of these patients are fluent, but there is an excessive use of function words and little real content, in addition to the fact that sentences with meaning are not put together. In addition, there are many problems when it comes to repeating the sentences heard.
In general, people with this type of aphasia do not completely give up speaking even though they do not understand or make themselves understood, and they have logorrhea (verbal incontinence) .
2. Broca’s aphasia
This type of aphasia, also known as expressive aphasia, differs from the previous one in that here language production is more affected than language comprehension , which in some cases remains almost intact.
The neurological alteration that produces this disorder is a lesion in Broca’s area, a part of the frontal lobe that intervenes in the production of language, although it also has a certain role in its comprehension.
Thus, people with Broca’s aphasia will understand what is said to them when they are spoken to, and it is also very likely that they will understand what they read, but they will be unable to speak and write with minimal fluency.
Compared with patients with receptive aphasia, patients with this language disorder prefer not to talk too much and do not have logorrhea. However, as in the previous case, problems will appear when repeating phrases that they hear others say.
3. Driving aphasia
This is one of the less frequent types of aphasia. It is characterized by preserving the ability to understand spoken language and to produce spoken language fluently (although it contains paraphrases, the substitution of syllables, words and phrases for others that do not make sense in that context).
The most affected area is the repetition of speech: by asking a patient with conduction aphasia to repeat a sentence, his speech fluency will disappear and he will have serious difficulties even when saying the first syllable.
The damaged part of the brain that is the cause of this type of aphasia is thought to be the arcuate fasciculus, a group of neurons that connect Broca’s and Wernicke’s areas to each other, although it is more likely that there are other, more complex areas as well. surface areas that are affected.
4. Motor transcortical aphasia
In motor transcortical aphasia, the ability to repeat sentences heard remains almost intact, but there are severe difficulties when initiating speech , while language comprehension is less impaired.
It is believed that the cause of this type of aphasia lies in a lesion in certain areas of the frontal lobe, whose dysfunction would mean that there is hardly any connection between the parts of the brain responsible for the production of speech and the executive functions, dedicated to initiating actions by own will.
5. Sensory transcortical aphasia
As happens in motor transcortical aphasia, in this alteration the ability to repeat what others say orally is preserved relatively well, but unlike the previous one, speech is fluent (although with substitution of words for others that are inadequate) and language comprehension is poor.
Thus, sensory transcortical aphasia is similar to Wernicke’s aphasia, but unlike Wernicke’s, the sentences heard can be repeated.
The brain damage associated with this type of aphasia is similar to that behind Wernicke’s, although somewhat lower, so that Wernicke’s area is not as damaged as in receptive aphasia.
6. Anomic or amnesic aphasia
As its name suggests, this disorder is characterized by anomie: the inability or difficulty in finding the right word to express something . It belongs to the type of fluent aphasia, such as Broca’s or driving, but unlike what happens in these, the inability to put together a coherent speech does not appear constantly and distributed in everything that is said, but rather more isolated, at times when finding a specific word counts.
On the other hand, patients with this condition have certain problems when it comes to repeating sentences and understanding spoken language, but they do not get completely blocked when trying, as happens with other types of aphasia.
It is not known in detail what lesions are the cause of this alteration, but it is hypothesized that they occur in the parietal and temporal lobes of the cerebral hemisphere in which language processes predominate.
7. Overall aphasia
Global aphasia is the closest thing there is to a disorder that affects all mental processes related to the production and comprehension of language , including the repetition of language. Thus, it is a type of non-fluent aphasia in which you cannot repeat what others say and you cannot understand what you have heard or read.
Normally, the brain lesions that produce it affect large areas of the cerebral hemisphere in which language dominates, especially Wernicke’s area and all the areas in the rear area of the Silvio fissure, although parts linked to the area are also usually damaged. of Broca.
Bibliographic references
- Kuljic-Obradovic, D.C. (2003). Subcortical aphasia: three different language disorder syndromes?. European Journal of Neurology.
- Nolen-Hoeksema, S. (2014). Neurodevelopmental and Neurocognitive Disorders. In Abnormal Psychology (6th ed.). New York: McGraw-Hill.
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