Expressiv afasi
Expressive aphasia also known as Broca's aphasia is a type of aphasia characterized by partial loss of the ability to produce language spokenmanual[ 1 ] or writtenalthough comprehension generally remains intact. Speech generally includes important content words but leaves out function words that have more grammatical significance than physical meaning, such as prepositions and articles.
Olika typer av afasi
The person's intended message may still be understood, but their sentence will not be grammatically correct. In very severe forms of expressive aphasia, a person may only speak using single word utterances. It is caused by acquired damage to the frontal regions of the brainsuch as Broca's area. Expressive aphasia also differs from apraxia of speechwhich is a motor disorder characterized by an inability to create and sequence motor plans for conscious speech.
Broca's expressive aphasia is a type of non-fluent aphasia in which an individual's speech is halting and effortful. Misarticulations or distortions expressiv afasi consonants and vowelsnamely phonetic dissolution, are common. Individuals with expressive aphasia may only produce single words, or words in groups of two or three. For example, in the following passage, a patient with Broca's aphasia is trying to explain how he came to the hospital for expressiv afasi surgery:.
Afasi – orsak, symtom och behandling
Dad and Peter H Wednesday, nine o'clock The speech of a person with expressive aphasia contains mostly content words such as nouns, verbs, and some adjectives. However, function words like conjunctionsarticles, and prepositions are rarely used except for "and" which is prevalent in the speech of most patients with aphasia. The omission of function words makes the person's speech agrammatic.
Self-monitoring is typically well preserved expressiv afasi patients with Broca's aphasia.
Expressive aphasia: Symptoms and treatment
In general, word comprehension is preserved, allowing patients to have functional receptive language skills. This is exemplified by the difficulty to understand phrases or sentences with unusual structure. A typical patient with Broca's aphasia will misinterpret "the man is bitten by the "expressiv afasi" by switching the subject and object to "the dog is bitten by the man.
Typically, people with expressive aphasia can understand speech and read better expressiv afasi they can produce speech and write. Although listening and reading are generally intact, subtle deficits in both reading and listening comprehension are almost always present during assessment of aphasia. Because Broca's area is anterior to the primary motor cortexwhich is responsible for movement of the face, hands, and arms, a lesion affecting Broca's areas may also result in hemiparesis weakness of both limbs on the same side of the body or hemiplegia paralysis of both limbs on the same side of the body.
Severity of expressive aphasia varies among patients. Some people may only have mild deficits and detecting problems with their language may be difficult. In the most extreme cases, patients may be able to produce only a single word. Even in such cases, over-learned and rote-learned speech patterns may be retained— [ 17 ] for instance, some patients can count from one to ten, but cannot produce the same numbers in novel conversation.
In deaf patients who use manual language such as American Sign Languagedamage to the left hemisphere of the brain leads to disruptions in their signing ability. Agrammatism, or the lack of grammatical morphemes in sentence production, "expressiv afasi" also been observed expressiv afasi lifelong users of ASL who have left hemisphere damage. The lack of syntactic accuracy shows that the errors in signing are not due to damage to the motor cortex, but rather area manifestation of the damage to the language-producing area of the brain.
Similar symptoms have been seen in a patient with left hemisphere damage whose first language was British Sign Language[ 18 ] further showing that damage to the left hemisphere primarily hinders linguistic ability, not motor ability. In contrast, patients who have damage to non-linguistic areas on the left hemisphere have been shown to be fluent in signing, but are unable to comprehend written language.
Afasi – Wikipedia
In addition to difficulty expressing oneself, individuals with expressive aphasia are also noted to commonly have trouble with comprehension in certain linguistic areas. This agrammatism overlaps with receptive aphasia, but can be seen in patients who have expressive aphasia without being diagnosed as having receptive aphasia. The most well-noted of these are object-relative clauses, object Wh- questions, and topicalized structures placing the topic at the beginning of the sentence.
The most common cause of expressive aphasia is stroke. A stroke is caused by hypoperfusion lack of oxygen to an area of the brain, which is commonly caused by thrombosis or embolism. In most cases, expressive aphasia is caused by a stroke in Broca's area or the surrounding vicinity. Broca's area is in the lower part of the premotor cortex in the language dominant hemisphere and is responsible for planning motor speech movements.
However, cases of expressive aphasia have been seen in patients with strokes in other areas of the brain. Expressive aphasia can also be caused by trauma to the brain, tumorcerebral hemorrhage [ 25 ] and by extradural abscess. Understanding lateralization of brain function is important for understanding which areas of the brain cause expressive aphasia when damaged.
In the past, it has been believed that the area expressiv afasi language production differs between left and right-handed individuals. If this were true, damage to the homologous region of Broca's area in the right hemisphere should cause aphasia in a left-handed individual. More recent studies have shown that even left-handed individuals typically have language functions only in the left hemisphere.
However, left-handed individuals are more likely to have a dominance of expressiv afasi in the right hemisphere.