Wernicke's aphasia: description, symptoms and causes

Strokes and head 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 brain structures or connections that control these functions. We refer to these disorders as "aphasias."

In this article we will describe the main symptoms and the most common causes of Wernicke's aphasia, which is characterized by a pronounced deficit in language comprehension 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 damage to the brain. Depending on the regions and neural pathways that are affected, very different signs can appear, which gives rise to the different types of aphasia.

However, in many cases the deficits combine differentiated alterations or are generalized. When the latter happens, usually as a consequence of massive damage to the left hemisphere of the brain, we speak of global or total aphasia.

Some of lThe basic criteria used to classify aphasias 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, correctness of syntax and the presence of unintended phonemes or wrong.

Since the brain structures that control speech production and comprehension correspond to the areas responsible for speech literacy, the deficits of aphasia appear not only in relation to spoken language but also in the writing.

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Description of Wernicke's aphasia

Wernicke's aphasia is characterized mainly by the presence of difficulties in understanding language, which in turn leads to an inability to repeat other people's words; This criterion is very relevant in the neuropsychological evaluation of aphasias.

On the contrary, and unlike what happens in other aphasias (in particular in Broca's), in Wernicke remains fluent in speech - in fact, in many cases he becomes excessively fluent. However, frequent errors appear and patients are usually not aware of them.

According to Aleksandr Luria, who calls this disorder "acoustic-agnosic aphasia", the key problem in Wernicke's aphasia is found in the analysis and synthesis of phonemes during the speech perception process; the deficit is due to lesions in the secondary language areas, which control these functions.

This type of aphasia It is also known as "receptive", "sensory", "comprehension", "acoustic", "syntactic" and "central" aphasia.. 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 which occurs normally as a result of chronic alcoholism or other factors that cause a deficiency of thiamine (vitamin B1), such as malnutrition.

• You may be 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. Even though this has normal rhythm, fluency, and prosody, is characterized by frequent repetitions, mistakes, 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 proper language processing. Among the main clinical characteristics of this disorder we find the following:

• Severe deficit in listening and reading comprehension of language.
• Inability to repeat words and phrases correctly.
• Difficulty remembering or pronouncing names of objects and living things (anomie).
• Maintenance or excess of the fluency of speech and writing.
• Absence of alterations in the articulation of phonemes.
• Substitution of words for others with a similar meaning (semantic paraphasias).
• Use of words without meaning (neologisms).
• Incomprehensible and incoherent speech and writing due to 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 to certain regions of the brain is susceptible to cause aphasia: head injuries, brain tumors, neurodegenerative disorders, infections viral ...

In the case of Wernicke's aphasia, the lesions are localized at the back of the superior gyrus of the left temporal lobe. This disorder was previously associated specifically with damage to the first temporal gyrus. upper left, which corresponds to area 22 of the classification made by Brodmann or "area of Wernicke ”.

Damage to this section of the superior temporal gyrus does not only affect the regions of the frontal lobe involved. directly into language, but also isolate them from most of the temporal, parietal, and occipital.