Wernicke's aphasia: description, symptoms and causes
Cerebrovascular accidents and traumatic brain injuries, among many other causes, can cause the appearance of alterations in the understanding or production of spoken and written language if they damage the structures or brain connections that control these functions. We refer to these disorders as "aphasias".
In this article we will describe the main symptoms and the most frequent causes of Wernicke's aphasia , which is characterized by a pronounced deficit in the understanding of language and other problems associated with it.
- Related article: "Aphasias: the main language disorders"
What are aphasias?
Aphasias are language disorders that occur as a result of injuries to the brain. Depending on the regions and neural pathways that are affected, very different signs may appear, which leads to different types of aphasia.
However, in many cases the deficits combine differentiated alterations or they occur in a generalized way. When the latter happens, usually as a result of massive damage in the left hemisphere of the brain, we speak of global or total aphasia.
Some of lThe basic criteria that are used to classify aphasias they are the degree of verbal fluency, the quality of the articulation of phonemes, the ability to understand and to repeat words spoken by other people, the correction of syntax and the presence of unintentional or erroneous phonemes.
Given that the structures of the brain that control the production and understanding of speech correspond to the areas responsible for literacy, the deficits of aphasia appear not only in relation to spoken language but also in writing.
- Maybe you're interested: "The 15 most frequent neurological disorders"
Description of Wernicke's aphasia
Wernicke's aphasia is mainly characterized by the presence of difficulties in understanding the language , which in turn leads to an inability to repeat the words of other people; this criterion is very relevant in the neuropsychological evaluation of aphasias.
On the contrary, and unlike what happens in other aphasias (particularly in Broca's), in Wernicke's the fluency of speech is maintained-in fact, in many cases it becomes excessively fluid. However, frequent errors appear and patients are not usually aware of them.
According to Aleksandr Luria, who calls this disorder "acoustic-agnostic aphasia," the key problem of Wernicke's aphasia is in the analysis and synthesis of phonemes during the process of speech perception ; the deficit is due to injuries in the secondary areas of language, which control these functions.
This type of aphasia it is also known as "receptive aphasia", "sensory", "comprehension", "acoustic", "syntactic" and "central" . These qualifiers refer to some of the most defining characteristics of Wernicke's aphasia, which we will describe in detail below.
It is important to differentiate Wernicke's aphasia from Wernicke-Korsakoff syndrome, a disorder that affects memory and other cognitive functions and that normally occurs as a consequence of chronic alcoholism or other factors that cause a deficiency of thiamine (vitamin B1), such as the desnutrition.
- Maybe you're interested: "Broca's aphasia: symptoms and causes of this disorder"
Symptoms and main characteristics
Wernicke's aphasia can be identified primarily from the speech of the affected person. Although this one has a normal rhythm, fluency and prosody , is characterized by frequent repetitions, errors and the inclusion of meaningless words and phrases.
The most characteristic symptoms and features of Wernicke's aphasia are associated with receptive deficits, which impede the adequate processing of language. Among the main clinical features of this disorder we find the following:
- Severe deficit in listening comprehension and reading of the language .
- Inability to repeat words and phrases correctly.
- Difficulty remembering or pronouncing names of objects and living beings (anomie).
- Maintenance or excess of fluency of speech and writing.
- Absence of alterations in the articulation of phonemes.
- Substitution of words by others with a similar meaning (semantic paraphasias).
- Use of words without meaning (neologisms).
- Incomprehensible and incoherent speech and writing by the so-called "word salad".
- Lack of awareness of linguistic errors (anosognosia).
Causes of this disorder
Aphasias occur normally as a result of strokes , although any other type of factor that causes damage in certain regions of the brain is likely to cause aphasia: traumatic brain injuries, brain tumors, neurodegenerative disorders, viral infections ...
In the case of Wernicke's aphasia the lesions are localized in the posterior part of the upper rotation of the left temporal lobe . Previously this disorder was specifically associated with damage to the first left superior temporal gyrus, which corresponds to area 22 of the classification made by Brodmann or "Wernicke area".
Damages in this section of the temporal superior turn not only affect the frontal lobe regions directly involved in the language, but also isolate them from most of the temporal, parietal and occipital lobes.
