What is aphasia?
Aphasia, a disturbance in the formulation and comprehension of language, is due to damage to brain tissue areas responsible for language; aphasia may occur suddenly or develop over time, depending on the type and location of brain tissue damage.
- Strokes are a common cause of aphasia.
- Causes of aphasia are mainly due to strokes, severe head trauma, brain tumors, and brain infections; however, any brain tissue damage for whatever reason that occurs in the language centers of the brain may cause aphasia.
- Two broad categories of aphasia are fluent and non-fluent (also termed Broca's aphasia), but there are subtypes of these categories.
- Aphasia, especially a subtype, is diagnosed by tests given to people to determine the individual's ability to communicate and understand, using language skills; neurologists most frequently diagnose the type of aphasia.
- Aphasia is mainly treated by speech and language therapy and therapy methods are based on the extent and locale of the brain damage.
- Aphasia research is ongoing; studies include revealing underlying problems of brain tissue damage, the links between comprehension and expression, rehabilitation methods, drug therapy, speech therapy, and other ways to understand and treat aspects of aphasia.
What is aphasia?
Aphasia is a neurological disorder caused by damage to the portions of the brain that are responsible for language. Primary signs of the disorder include difficulty in expressing oneself when speaking, trouble understanding speech, and difficulty with reading and writing. Aphasia is not a disease, but a symptom of brain damage.
Who has aphasia?
Most commonly seen in adults who have suffered a stroke, aphasia can also result from a brain tumor, infection, head injury, or dementia that damages the brain. It is estimated that about 1 million people in the United States today suffer from aphasia. The type and severity of language dysfunction depends on the precise location and extent of the damaged brain tissue.
What are the types of aphasia?
Generally, aphasia can be divided into four broad categories: (1) Expressive aphasia involves difficulty in conveying thoughts through speech or writing. The patient knows what he wants to say, but cannot find the words he needs. (2) Receptive aphasia involves difficulty understanding spoken or written language. The patient hears the voice or sees the print but cannot make sense of the words. (3) Patients with anomic or amnesia aphasia, the least severe form of aphasia, have difficulty in using the correct names for particular objects, people, places, or events. (4) Global aphasia results from severe and extensive damage to the language areas of the brain. Patients lose almost all language function, both comprehension and expression. They cannot speak or understand speech, nor can they read or write.
What are the symptoms for aphasia?
Aphasia is a sign of some other condition, such as a stroke or a brain tumor.
A person with aphasia may:
- Speak in short or incomplete sentences
- Speak in sentences that don't make sense
- Substitute one word for another or one sound for another
- Speak unrecognizable words
- Not understand other people's conversation
- Write sentences that don't make sense
The severity and scope of the problems depend on the extent of damage and the area of the brain affected.
Types of aphasia
Your doctor may refer to aphasia as nonfluent, fluent or global:
Nonfluent aphasia. Damage to the language network near the left frontal area of the brain usually results in Broca aphasia, which is also called nonfluent aphasia. People with this disorder struggle to get words out, speak in very short sentences and omit words. A person might say "Want food" or "Walk park today." A listener can usually understand the meaning.
People with Broca aphasia may understand what other people say better than they can speak. They're often aware of their difficulty communicating and may get frustrated. People with Broca aphasia may also have right-sided paralysis or weakness.
- Fluent aphasia. People with this form of aphasia may speak easily and fluently in long, complex sentences that don't make sense or include unrecognizable, incorrect or unnecessary words. They usually don't understand spoken language well and often don't realize that others can't understand them. Also known as Wernicke aphasia, this type of aphasia is the result of damage to the language network in the middle left side of the brain.
- Global aphasia. Global aphasia results from extensive damage to the brain's language networks. People with global aphasia have severe disabilities with expression and comprehension.
When to see a doctor
Because aphasia is often a sign of a serious problem, such as a stroke, seek emergency medical care if you suddenly develop:
- Difficulty speaking
- Trouble understanding speech
- Difficulty with word recall
- Problems with reading or writing
What are the causes for aphasia?
The most common cause of aphasia is brain damage resulting from a stroke — the blockage or rupture of a blood vessel in the brain. Loss of blood to the brain leads to brain cell death or damage in areas that control language.
Brain damage caused by a severe head injury, a tumor, an infection or a degenerative process also can cause aphasia. In these cases, the aphasia usually occurs with other types of cognitive problems, such as memory problems or confusion.
Primary progressive aphasia is the term used for language difficulty that develops gradually. This is due to the gradual degeneration of brain cells located in the language networks. Sometimes this type of aphasia will progress to a more generalized dementia.
Sometimes temporary episodes of aphasia can occur. These can be due to migraines, seizures or a transient ischemic attack (TIA). A TIA occurs when blood flow is temporarily blocked to an area of the brain. People who've had a TIA are at an increased risk of having a stroke in the near future.
What are the treatments for aphasia?
If the brain damage is mild, it's possible to recover language skills without treatment. However, most people undergo speech and language therapy to rehabilitate their language skills and supplement their communication experiences. Researchers are investigating the use of medications, alone or in combination with speech therapy, to help people with aphasia.
Speech and language rehabilitation
Recovery of language skills is usually a slow process. Although most people make significant progress, few people regain full pre-injury communication levels.
Speech and language therapy aims to improve the ability to communicate. The therapy helps by restoring as much language as possible, teaching how to make up for lost language skills and finding other methods of communicating.
- Starts early. Some studies have found that therapy is most effective when it begins soon after the brain injury.
- Often works in groups. In a group setting, people with aphasia can try out their communication skills in a safe environment. Participants can practice starting conversations, speaking in turn, clearing up confusion and fixing conversations that have completely broken down.
- May include use of computers. Using computer-assisted therapy can be especially helpful for relearning verbs and word sounds (phonemes).
Brain stimulation is being studied for aphasia treatment and may help improve the ability to name things. But no long-term research has been done yet. One treatment is called transcranial magnetic stimulation and another is transcranial direct current stimulation.
These treatments aim to stimulate damaged brain cells. Both are noninvasive. One uses magnetic fields and the other uses a low current through electrodes placed on the head.
What are the risk factors for aphasia?
Risk factors for primary progressive aphasia include:
- Having learning disabilities. A learning disability might put you at somewhat higher risk of primary progressive aphasia.
- Having certain gene mutations. Rare gene mutations have been linked to the disorder. If several other members of your family have had primary progressive aphasia, you might be more likely to develop it.
Is there a cure/medications for aphasia?
Certain drugs are being studied for the treatment of aphasia. These include drugs that may improve blood flow to the brain, enhance the brain's recovery ability or help replace depleted chemicals in the brain (neurotransmitters). Several medications, such as memantine (Namenda), donepezil (Aricept, Adlarity), galantamine (Razadyne ER) and piracetam, have shown promise in small studies. But more research is needed before these treatments can be recommended.