All brain diseases can cause aphasia

Aphasia - language disorder & communication disorder

Aphasia: A central disorder of language

Acquired central language disorders that occur as a result of damage to localized areas of the brain, especially after a stroke, are called aphasia. Depending on the area affected, there are very different disruption patterns and side effects that make communication more difficult for those affected. Under favorable conditions and if the therapy is successful, the disorders are (partially) reversible. The exact characteristics and also the course are very individual. Older adults are mostly affected, but childhood aphasias are also less common, for example after an accident to the brain.

A brief overview

What is aphasia? How do aphasia occur? And what can those affected expect? The most important facts about these questions are briefly summarized in the following overview, while detailed information can be found in the article below:

  • definition: Aphasia is an acquired, centrally caused language disorder that occurs due to specific brain damage. The term means “missing language”, whereby there is usually no speechlessness, but different impairments of all language modalities. Those affected show deficits in speaking, understanding, reading and writing.
  • causes: Aphasia mainly occurs after a stroke. Most often there is an ischemic cerebral infarction, caused by a vascular occlusion. This can result from arterial embolism or from thrombosis of venous drainage vessels. But cerebral hemorrhages can also be the cause, as well as other locally limited brain injuries and brain diseases.
  • Course and prognosis: Every minute counts in an acute stroke. A dissolution of the thrombus (lysis), which closes the cerebral vessel, must take place no later than 4.5 hours after the onset of the first symptoms, according to the recommendation in the S1 guideline of the German Society for Neurology. All individual cases and thus also the course and prognosis are very individual, so that no general statements can be made. Aphasia is fundamentally and under favorable circumstances (partially) reversible and treatable. The success of the therapy and the duration depends on many factors.
  • diagnosis: While some test procedures allow the language disorder to be categorized and its severity determined as a snapshot, speech therapists still have sensitive and individually adapted methods to accurately diagnose aphasia, monitor its development and treat those affected accordingly.

Definition: aphasia as an acquired language disorder in all modalities

Aphasias are common neuropsychological syndromes that are characterized by a loss of or deficits in the area of ​​fully acquired language due to various circumscribed brain damage. Derived from the Greek, the word is made up of the prefix “a” (missing) and the term “phasiz” (language). As a rule, however, it is not a question of a complete loss of language, but rather different impairments of all four language modalities: language production, language understanding, reading and writing. This means that all language skills no longer work properly and the rule processes and systems previously stored in memory, which are necessary for every linguistic utterance, are no longer available to those affected to varying degrees. Aphasias are disorders of language formation, language memory and language understanding.

Usually the language modalities work closely and coordinated. If there is aphasia, for example, those affected write and say something different than what they think, or they read something aloud other than what they see with their eyes. Often, what is being said is also not perceived or heard. This is known as a parallelism disorder.

Aphasic disorders affect the subregions of language to varying degrees, resulting in many different forms and symptoms. For example, there may be difficulties in finding words, grammar, sentence formation and sound formation, which are noticeable both in speaking and in writing. It can happen that those affected can hardly express themselves or only incompletely and hesitantly or speak fluently with often incorrect and distorted words and sentences. Understanding can also have significant deficits.

A frequently used classification of the various forms of aphasia distinguishes between the most severe form, global aphasia, and the mildest form, amnestic aphasia. Other forms described in more detail are the so-called Broca aphasia (motor) and Wernicke aphasia (sensory).

Concomitant disorders

Other disorders often occur along with aphasia. For example, the coordination of movement sequences, including vocalization and breathing (dysarthria and dysarthrophonia), which are necessary for speech processes, can be impaired.

In the case of an accompanying apraxia, the planning of movements and sequences of movements is impaired, so that, for example, in a speech apraxia, individual sounds are not produced correctly and in a timely manner. Apraxia can also affect the mouth and face muscles or the limbs, so that everyday movements and actions can be restricted.

In addition to the disorders that primarily affect language, the existing brain damage can also lead to other side effects, such as perception and memory disorders, attention and concentration deficiencies, paralysis of one half of the body and face (hemiplegia and facial palsy) or one half-sided (often right-sided) visual field loss (hemianopia). With each of the other disorders mentioned, the ability to communicate verbally and non-verbally, for example using gestures and facial expressions, is reduced.

Relatives often also report mood swings and personality changes in those affected. It is often unclear whether this is a direct consequence of the brain damage or a secondary reaction to the changed life situation. Given the importance of language and communication in interpersonal relationships, be it professional or private, aphasia often has far-reaching psychosocial consequences.

In any case, the aphasia represents a more or less major change for the person affected as well as for the relatives and the immediate environment. Significant for everyday life and for (speech) therapy is the fact that multilingual aphasic patients have their mother tongue most likely to be preserved.

Differentiation from other language disorders

It is important that one only speaks of aphasia if language that has already been acquired is lost. This represents a decisive difference to other and above all congenital language disorders. In contrast to the language problems that exist with congenital deafness or deaf-muteness, extensive linguistic knowledge is still available in long-term memory with aphasia. However, the retrieval and use of this knowledge is impaired.

Aphasia also occurs due to damage to the dominant hemisphere that is limited to certain areas of the brain, but not in the case of diffuse diseases of the brain, which can also lead to speech disorders. Such generalized disorders, such as dementia, do not affect the language system, but disorders in consciousness, perception and thinking are also expressed in language.

In principle, aphasia can also occur in children and adolescents, for example after accidents with brain injuries. But this is rarely the case. It is important to differentiate aphasia from a delay in speech development that can occur in children and which can have similar symptoms. The elementary difference in speech disorders is evident in the various therapeutic approaches. While the language is gradually built up and expanded in a child with a speech developmental disorder, efforts are made in adults with aphasia to mobilize the language knowledge they still have and make it usable again.


The quantitative occurrence of aphasia is still little known. In Germany, around 50,000 new cases of aphasia are expected solely due to strokes. Since many aphasias persist for many years, the prevalence is estimated at 70,000 to 80,000 cases in Germany.

In principle, people of all ages can be affected by aphasia, with (older) adults mainly suffering from this acquired language disorder. According to the Bundesverband Aphasie e.V., aphasia occurs in around 3,000 children and adolescents in Germany every year, particularly as a result of a traumatic brain injury.


Around 80 percent of brain injuries that cause aphasia are stroke (apoplexy) and the damage associated with it. Strokes are the main cause of aphasic disorders. In the vast majority of cases (around 85 percent) ischemic cerebral infarctions are the cause, the so-called white strokes. This leads to a narrowing of the vessels, which results in an insufficient supply of oxygen and glucose in certain arterial areas of the brain. This is often triggered by a so-called thromboembolism, in which a thrombus (blood clot) is washed away from the heart in the blood, for example, and closes a part of a vessel or an entire branch of the vessel elsewhere in the brain.

Far less often (around 15 percent) it is a stroke due to a cerebral hemorrhage, in which, for example, a vessel that has been damaged by arteriosclerosis bursts and bleeds into the brain. But other vascular diseases can also play a role.

Other rare causes of aphasia are skull injuries due to accidents (traumatic brain injury), brain tumors, other brain diseases or operations that lead to damage in the dominant hemisphere.

Most of the time, the left hemisphere is the dominant side on which the language is programmed and provided. This is supplied with blood through three large arteries. The most important of these is the middle cerebral artery (middle cerebral artery), which also supplies the areas of the brain that are important for speech. In the case of strokes of the left hemisphere, it is precisely this supply area that is preferably affected, which is then referred to as media infarction. The size and exact location of the resulting lesion largely determine the severity and prognosis of the speech disorder.

Course and prognosis

A number of different factors play a role in whether, to what extent and in what period of time a lost language ability can be regained. In principle, the cause and severity of the disorder have a significant impact on recovery and the success of the therapy. Those affected with initially only slight language deficits usually have a better chance of complete rehabilitation than those with a severe form. Nevertheless, a favorable course is possible even with severe aphasia.

What the success of the therapy ultimately depends on and the period in which progress can be made is always individually dependent on the personal situation and the exact appearance, including possible accompanying symptoms (physical and psychological). No aphasia can be directly compared with any other and great caution is required when making statements about possible duration of therapy. What is certain is that the earlier a therapy starts, the better the chances of success.

According to the German Society for Neurology, more than 60 percent of those affected with initial aphasia no longer have a language disorder after six months. In about a third, the disorders largely normalize even in the first four weeks, which is referred to as spontaneous regression. Further studies indicate that within a year of occurrence, the remaining communication disorders decrease even further. But progress can still be made beyond the first year.


Various tests are available in the acute and post-acute phase for diagnosis and to determine the severity, such as the token test, the Aachen aphasia bedside test (AABT) and the Aachen aphasia test (AAT). However, these tests are to be viewed as snapshots and do not provide fully valid results. Since the disturbance patterns depend on many factors, vary greatly and develop, such test results must be updated and checked on an ongoing basis. The classifications can help to make better prognoses and to adjust the treatment options accordingly.

Such tests are often only carried out when the person concerned is physically and mentally stable enough for such a stressful performance record. In professional speech therapy, as a central element of every aphasia treatment, further careful and personally tailored methods are usually used for precise diagnostics and for individual therapy planning. (jvs, cs)

Author and source information

This text complies with the requirements of specialist medical literature, medical guidelines and current studies and has been checked by medical professionals.

Dr. rer. nat. Corinna Schultheis, Dr. med. Andreas Schilling
  • Lutz, Luise: Understanding the Silence: About Aphasia, Springer, 4th revised. Edition, 2011
  • Masuhr, Karl F. / Masuhr, Florian / Neumann, Marianne: Neurologie, Thieme, 7th edition, 2013
  • Huber, Walter / Poeck, Klaus / Springer, Luise: Clinic and rehabilitation of aphasia: An introduction for therapists, relatives and those affected, Thieme, 2006
  • Schneider, Barbara / Wehmeyer, Meike / Grötzbach, Holger: Aphasia: Ways out of the language jungle, Springer, 6th edition, 2014
  • German Federal Association for Academic Speech Therapy and Speech Therapy e.V .: Information brochure on aphasia (accessed: 26.06.2019),
  • Revenstorf, Dirk (Ed.), Peter, Burkhard (Ed.): Hypnosis in Psychotherapy, Psychosomatics and Medicine: Manual for Practice, Springer, 3rd revised. and act. Edition, 2015
  • German Society for Neurology (DGN): S1 guidelines for rehabilitation of aphasic disorders after stroke, as of September 2012,
  • Federal Association for the Rehabilitation of Aphasia V .: Aphasia (accessed: June 26, 2019),
  • German Stroke Foundation: Forms and Effects of Aphasia (accessed: June 26, 2019),
  • Mayo Clinic: Aphasia (accessed: June 26, 2019),

Important NOTE:
This article is for general guidance only and is not intended to be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor.

ICD codes for this disease: F80, R47 ICD codes are internationally valid codes for medical diagnoses. They can be found, for example, in doctor's letters or on certificates of incapacity for work.