It is the loss of ability to produce or understand language due to lesions in brain areas. People with this type of aphasia have great difficulty in speaking , it is like a conversational language .
Left cerebral hemisphere as the basis of language
Although similar in appearance, the cerebral hemispheres specialize in different functions. One of the best known is the specialization of the left hemisphere in most people as the basis of verbal language . The understanding of the non-verbal aspects of language and of prosody (phonetics) and its rhythm are located in the right hemisphere.
This is so for 95 % of right-handed people and 70 % of left-handed people, being partially or totally lateralized on the right side in the rest. The left hemisphere is also responsible for controlling the motor skills of the members of the right hemibody (half of the body). In addition, the motor areas are physically close to those of the language , so it is common for some subtypes of aphasia to be accompanied by hemiparesis (inability to move).
Causes of aphasia
Aphasia can be caused by stroke , trauma, brain infection, or neoplasia .
- Cerebrovascular accident or stroke: it is the most frequent cause of aphasia, especially that produced by thrombotic or embolic ischemia .
- Head injury: usually caused by an accident.
- Localized or diffuse infections of the brain, such as brain abscess or encephalitis.
- Tumors of the Central Nervous System
Classification of aphasias
- Broca’s aphasia (motor)
It is produced by injury to the left inferior frontal gyrus (Broca’s area) and adjacent areas. It is characterized by the almost impossibility to articulate and the use of short phrases (telegraphic speech), which are produced with great effort and aprosodia.
- Transcortical motor aphasia
In this case there are problems similar to those of Broca’s aphasia. Usually due to a small subcortical lesion above Broca’s area
- Wernicke’s aphasia
The speech is in this case fluent, although with a high number of substitutions and paraphasias. Added to this are comprehension difficulties.
- Global aphasia
Speech disorders are severe, there are fluency and comprehension problems. Communication is often severely impaired
Treatment
In some cases an individual will fully recover from aphasia without treatment. This type of spontaneous recovery usually occurs after a transient ischemic attack (TIA), a type of stroke in which blood flow to the brain is momentarily interrupted but quickly restored. In these circumstances, language ability may return within a few hours to a few days; however, in most cases of aphasia, recovery of language ability is not nearly as fast, and even less complete.