Classification and characteristics of different forms of aphasia
Acquired speech disorder (aphasia) occurs after circumscribed brain damage, in most cases due to a stroke. Depending on which area of the brain is affected, different and very individual disturbance patterns can be seen. In everyday clinical practice, one often refers to a division into global aphasia, Broca aphasia, Wernicke aphasia and amnestic aphasia. In most cases, the symptoms change and improve in the course of the disease. The loss of speech is by no means a disturbance of thinking and is not synonymous with a loss of communication skills.
A brief overview
The variety of individual disorder patterns in aphasia and the occurrence of mixed and special forms mean that there is no generally applicable classification that is used without restriction in everyday clinical practice. The most comprehensive (but still rough) orientation is provided by the classification according to Poeck et al. (1989), which is also widely used in practice. This classification is based on aphasias caused by a stroke. A distinction is made between 4 syndromes: global aphasia, Broca aphasia, Wernicke aphasia and amnestic aphasia.
The following characteristic features are described as key symptoms for the respective forms, a speech and communication disorder acquired through a cerebral infarction, and occur in very different degrees in the sick:
- Global aphasia: Serious disturbances of all language modalities (speaking, understanding, reading, writing) and largely incomprehensible or missing statements.
- Broca aphasia: Main disorder of motor speech functions and speech production with a slow, non-fluid, agrammatic and telegram-style speech.
- Wernicke's aphasia: Disorder of the sensory language center with a limited understanding of the language and a fluent and excessive, but often incomprehensible language.
- Amnestic aphasia: Word-finding disorder, which enables communication as far as possible, but causes a stagnant, inaccurate and tedious speech ability.
Since this classification only shows a tendency of the respective form and hardly takes into account possible accompanying symptoms, a precise individual diagnosis of the disorder is essential, especially for an appropriate consideration of the treatment options for aphasia. It is assumed that there is an acute phase in the first four to six weeks, in which the syndromes are still subject to major changes and are less typical than at a later point in time. The symptoms also usually improve much more clearly in this initial phase than in the post-acute phase (from six weeks to one year after the event) or in the chronic phase (from one year after the event).
There are also aphasias that occur as a result of tumors, injuries and bleeding and do not correspond to the described forms. There are also combinations of disorders in which, for example, neuropsychological disorders are added to aphasia. This can lead to the fact that aphasia is not clearly recognized or accompanying symptoms such as poor memory and concentration or confusion can be erroneously attributed to aphasia. Other special features can be found in children and multilingual people.
Global aphasia: when all symptoms come together
People with global aphasia are most restricted because all language skills are severely impaired. This occurs when the main trunk of the middle cerebral artery (arteria cerebri media) is affected by a stroke and causes an interrupted blood supply in a relatively large area in the brain. The speech is then missing completely or is incomprehensible.
Repetitions of words, syllables or sounds ("tamtamtamtam") often occur, or the same phrases and idioms are used again and again ("Oh, man!" And "oje, oje, oje"), which are known in the professional world as stereotypes and automated speech systems can be designated. Affected people can only produce words or sequences of sounds with great effort and the statements usually make no sense to the listener. In very severe cases, the spontaneous speech is completely on these so-called recurring utterances reduced. Monophasia is a special form in which those affected can only reproduce individual words or fragments of sentences.
Understanding is also impaired in global aphasia, as are reading and writing. The latter not only affects free writing, but also the ability to copy can be lost. In many cases there is - at least temporarily and especially in the early stages - an immense communication impediment. In addition, there is a lack of awareness of the senseless statements, especially at the beginning. Affected people don't always hear what they're saying at the same time. And even if the problem is identified, the ability to speak - even with great effort to improve expression - generally remains severely impaired. Sometimes global aphasia can improve over the course of time and change into the forms of Broca or Wernicke aphasia or other mixed forms.
Broca aphasia: Above all, a disorder in speech production
If the supply area of the praerolandica artery (branch of the cerebral artery) is affected in the event of a stroke, damage usually occurs in the so-called Broca area. This is a region of the cerebral cortex that is mostly located in the left hemisphere and is named after its discoverer, the French surgeon Paul Broca (1824-1880). This area of the brain is one of the two main components of the language center and mainly performs motor functions. The sensory functions are assigned to the other component and located in the so-called Wernicke area. The language disorder defined by Broca is similar to "motor aphasia" (another common classification), but takes more into account the complex relationships of the language.
Damage in the area of this motor language region mainly affects speaking, while speech comprehension is largely preserved. The language is slowed down, fluid, agrammatic and telegram-style. Usually only short sentences are formed, in which the verbs are not conjugated and articles, prepositions and other function words are missing (for example "Young school" instead of "The boy goes to school"). What is typical is a spontaneous speech that can only produce individual words and partial sentences with great effort and with many pauses. Overall, the vocabulary appears to be limited and the reduced, robot-like style of speech makes it difficult to identify the conveyed feelings of the speaker in addition to the content. In contrast, aphasicians themselves perceive the intonation and gestures and facial expressions of their interlocutors very well and quickly and reliably recognize the content of non-verbal communication.
Furthermore, there is a mix-up of words within the words (phonematic paraphasias, for example, "ax" to "pencil") and sometimes meaning-related words (semantic paraphasies, for example. "Pencil" to "ballpoint pen"). If dysarthria is added, the spoken language is even more impaired and appears indistinct, or some sounds can no longer be formed.
Writing is usually affected in the same way as speaking. In contrast, speech comprehension and reading are often only slightly disturbed. In more serious cases, those affected can also have great difficulty tracking conversations and fully understanding their interlocutor. Among other things, this is often due to a slowdown in speech processing, which leads to more problems when listening than when reading.
The development of this language disorder is very individual and depends on various factors. In the best case, Broca aphasia can change to amnestic aphasia and gradually adapt to the original speech behavior.
Wernicke's aphasia: A limited understanding of language
If the sensory language center is affected by a stroke, this is due to an insufficient supply in the area of the temporal artery posterior, which lies in the rear section of the first temporal fold. The German neurologist Carl Wernicke (1848–1905) first described the Wernicke area, which was located here and later named after him. This area can only be found in the dominant hemisphere, in which speech is processed both by motor and sensory means. This is usually left for right-handed people, left or right for left-handed people. In the past, the term “sensory aphasia” was also used for this form of speech disorder.
The symptoms relate primarily to language comprehension and self-awareness. In contrast to Broca aphasia, those affected have a fluent and rather exaggerated language, which, however, often uses words incorrectly, is distorted in terms of sound and nested incorrectly, so that sentences and parts of sentences appear to be meaningless (paragramatism). Often, the sentences formed are ineffective and in many cases there are confusion of words and even the formation of new words (neologisms, for example "learning house" for "school").
The term "Wernicke jargon" or "jargon aphasia" describes the most severe form of this form, in which almost only word replacements are used that no longer reveal the actual content of what has been said. There is a risk that these jargon phasicians will be mistakenly thought to be mentally disturbed or mentally confused.
It is not uncommon for a continuous flow of speech (logorrhea) to be difficult to interrupt. This seems to be connected with the fact that parts of the sentence and words that have to be uttered buzz through the mind non-stop. This makes it difficult for the sick to adjust and listen to the conversation partner. For example, Wernicke aphasicians often cannot understand what others are telling you. Often, however, self-awareness is also disturbed among those affected. Then they don't hear that they speak incomprehensibly or what they say, but hear what they want to think and say.
Because of the problems of understanding and the disturbed self-perception, interpersonal interaction is often more difficult than with other forms. But even if the people affected can hardly make themselves clear in terms of content, the mood and intention of the speaker are quite clear. The transporting melody and emphasis is usually preserved.
Reading and writing skills are equally affected, with reading being particularly affected by impaired language understanding. The written language often improves faster, so that writing and reading often represent the start of therapy.
As with Broca aphasia, favorable developments can allow a transition to amnestic aphasia and gradually return to normal speech behavior.
Amnestic aphasia: lack of access to your own vocabulary
This mildest form of aphasic disorder cannot be assigned to a specific brain region like the other forms of damage. Different causes lead primarily to a word finding disorder, which also occurs with the disorder patterns of other aphasias. Typically, those affected come to a halt when they want to say something specific. Loud and word mix-ups occur less and mostly in connection with the search for a certain word.
In amnestic aphasia, replacement strategies can facilitate communication, such as rewriting and querying words or repeating words of the interlocutor. Those affected remain largely able to communicate. Despite an almost normal language ability, the utterances often seem cumbersome, imprecise, structureless and tedious. Writing skills are also affected by the word-finding disorder. Reading and understanding, on the other hand, are hardly disturbed.
With these comparatively light symptoms, the aphasic sufferers no less from the language failures. Simple jobs at work and in private life such as phone calls and shopping can become major hurdles in everyday life and can lead those affected into strange and uncomfortable situations.
Other concomitant disorders often occur together with aphasia. Typical symptoms are the following impairments:
- Dysarthria: Disruption of the control and coordination of speech movements,
- Apraxia: Disturbance in the planning of movement sequences (frequent impairment of the speaking apparatus, the mouth and face muscles and the limbs),
- Disorder of verbal learning and verbal memory,
- Difficulty concentrating,
- Perseverations (unintentional repetitions of language and non-linguistic actions),
- Paralysis and loss of visual field.
This all complicates the communication skills of an aphasic person and sometimes the disorders are difficult to distinguish from each other (especially with apraxia and dysarthria). Nevertheless, it is important that all disorders are treated accordingly. (jvs, cs)
Author and source information
This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
Dr. rer. nat. Corinna Schultheis
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- Federal Association for the Rehabilitation of Aphasicians e. V .: Aphasia (call: June 26, 2019), aphasiker.de
- German Stroke Aid Foundation: Forms and Effects of Aphasia (Call: June 26, 2019), schlaganfall-hilfe.de
- Mayo Clinic: Aphasia (call: June 26, 2019), mayoclinic.org
ICD codes for this disease: F80, R47ICD codes are internationally valid encodings for medical diagnoses. You can find yourself e.g. in doctor's letters or on disability certificates.