The 6 types of aphasia (causes, symptoms and characteristics)

The term language refers to the selection and ordering of words according to the rules. When this language is produced orally or verbally, a series of acquired skills is needed, both at a vocal, auditory, visual and motor level; in order to achieve correct communication.

However, when a person suffers some type of brain injury, aphasias can appear, which, strictly speaking, are disorders in the use of language, accompanied by a speech disorder.

However, there are different types of aphasias depending on the areas of the brain injured; as well as according to what symptoms the person presents.

• Recommended article: "Aphasias: the main language disorders"

What is aphasia? Definition and causes

Mainly, aphasia is the total or partial inability to use language. The deficits related to the different types of aphasia range from trouble finding words to the complete inability to speak.

Likewise, the different aphasias also include problems in written language, oral comprehension, reading or having to operate with numbers. In other cases, people have deficits in oral expression but keep their comprehension capacity intact. That is why it is necessary to detect in each patient what specific speech and language alterations they are subjected to in order to develop an adapted treatment.

The causes of aphasia are varied, but all occur in circumstances of brain injury:

• Head trauma
• Tumors of the central nervous system
• Stroke (most common cause of aphasia)
• Degenerative diseases (Alzheimer disease, Parkinson's disease, etc.)
• Localized or diffuse infections of the brain

Types of aphasia

The symptoms of aphasias depend both on the location of the brain lesions and on the compensatory reactions of the brain tissue that remains intact.

However, there are a series of common brain lesions that seem to group certain dysfunctions.

1. Broca's aphasia or major motor aphasia

In the Broca's aphasia deficits in the motor aspects of language and writing predominate, it is also accompanied by agrammatism and in many cases to language comprehension disorders. On occasion, sensory problems may appear on the right side and hemiparesis, which refers to a decreased motor strength or partial paralysis affecting only one arm or one leg on the same side of the body.

This aphasia is the consequence of a large lesion that includes the cortical and subcortical elements along the frontal and superior portion of the Silvio fissure, also including the insula; but its name comes from the implication that the inferior frontal gyrus or Broca's area has in this disorder.

The most common causes of Broca's aphasia can be:

• Embolic occlusion of the superior division of the left middle cerebral artery
• Frontal lobe abscess
• Tumor Hypertensive hemorrhage of putamen
• Metastatic lesions
• Subdural hematoma

During the evolution of Broca's aphasia, the patient may be in the acute or subacute phase. While the acute phase occurs, the patient is practically mute, he cannot understand and is unable to communicate; also suffering a strong emotional impact. As the patient progresses, comprehension begins to improve, while deficits in language and writing persist. As this improves, he is able to speak aloud, not without much slowness and effort.

Articulation and intonation are also affected, so language becomes primarily a speech of nouns and adjectives in which functional words such as articles, prepositions or conjunctions; becoming an ungrammatical and telegraphic language.

After the acute and subacute phases, speech difficulties may persist. However, a therapy in which language is worked can significantly improve the patient's condition.

Finally, due to paralysis of the right hand, many patients cannot continue to write with the right hand; so it requires a reeducation of writing with the left hand or take advantage of new technologies to enable communication.

2. Transcortical motor aphasia

This aphasia manifests similar problems to Broca's aphasia. The main difference is that transcortical motor aphasia there is a deficit in speech production, especially when starting a speech, in the spontaneity or in the organization of this.

The articulatory aspect of speech is usually not difficult, and understanding of language remains intact, as does the production of names of places and people.

The cause of problems similar to those of Broca's aphasia may be due to the fact that the genesis of the disorder is due to a small subcortical lesion above Broca's area. At present, the implication of a circuit from the supplementary motor area, through the subcallosal fascicle to the basal ganglia and Broca's area.

3. Wernicke's aphasia

Wernicke's aphasia is characterized by fluent speech but with a large number of substitutions and paraphasiaalong with difficulties in understanding.

During the subacute phase, understanding of language is usually very impaired in severe cases, reaching complete misunderstanding. However, speech is easily, clearly and correctly articulated, and the rhythm contour is similar to that of normal speech. After these phases, listening comprehension tends to improve and paraphasia is reduced.

If compared to Broca's aphasia, in the Wernicke's aphasia functional words are present, but there are semantic and grammatical confusion. In addition, in this type of aphasia the motor area is intact so there is no paralysis on the right side, for what patients can write, even though the content is disorganized and confusing, as is the speaks.

4. Conduction aphasia

In this syndrome, what is seriously impaired is repetition. Conduction aphasia is a fluid aphasia with almost normal understanding; but in which, in severe cases, fluency is seriously compromised due to problems in isolated word production; thus becoming a sequential speech and short sentences.

Traditionally, it has been believed that this aphasia appeared as a consequence of a lesion in the fibers that connect the Broca and Wernike areas. But it has been discovered that there is also an association with lesions in the superior temporal gyrus and in the insula.

In addition to difficulties in repetition, these patients have problems with word selection and phonemic sequencing within individual words.

5. Global aphasia

People with global aphasia suffer from severe speech disorders, including fluency and comprehension problems; so communication is strictly affected.

The most common cases are those in which patients can only say a few words and their understanding of language is also very limited, since they cannot read or write either.

The most common cause of global aphasia is a lesion that destroys much of the speech-related areas of the dominant hemisphere and arising from obstruction of the left internal carotid artery or cerebral artery half.

6. Amnesic or anomic aphasia

Since anomia is a common feature of fluent, Wernicke's and conduction aphasia, only anomic aphasia will be discussed. when the difficulty of finding commonly used words appears relatively isolated.

Bibliographic references:

• Kuljic-Obradovic, D.C. (2003). Subcortical aphasia: three different language disorder syndromes?. European Journal of Neurology. 10 (4): 445–8.