Aphasia

What is it?
Aphasia is the partial or total loss of the ability to understand words and use language because of a brain injury
Who gets it?
Aphasia often occurs in people who have had a stroke. In fact, 20% of all people who have a stroke each year, develop some type of aphasia. People who have suffered brain damage from a head injury, infection (such as encephalitis), or brain tumor may develop aphasia. Aphasia also occurs in people with Alzheimer's disease. Researchers have found no connection between aphasia and age, gender, or race.
What causes it?
To understand what causes aphasia, it helps to know a little bit about the structure of the brain. The main portion of the brain, the cerebrum, is divided into halves called the left and right hemispheres. The cerebrum is further divided into lobes, the frontal, parietal, occipital, and temporal. In most people, language control is located in the left hemisphere of the brain, called the language dominant area of the brain. It is here that we store information about word meaning, how to formulate spoken and written language, and how and when to use words properly. So, damage to the left hemisphere most often results in the symptoms of aphasia. However, research has shown that many left-handed people have language areas in both the left and right hemispheres of the brain. These people can develop aphasia from damage to either side of the brain. Injuries that result in aphasia can be caused by stroke, head injury, brain tumor, or infection.
Types of aphasia are classified according to the area of the brain that is injured. One type, called Broca's aphasia, results from damage to the frontal lobe of the language-dominant area of the brain. Wernicke's aphasia is caused by damage to the temporal lobe, or the side portion, of the language-dominant area of the brain. Global aphasia is caused by damage to both the left temporal and frontal lobes. Transcortical aphasia is caused by damage to the language areas of the left hemisphere that are outside the primary language areas. Subcortical aphasia results from damage to areas of the brain that are not language-dominant areas.
What are the symptoms?
The symptoms of aphasia may be temporary or permanent, depending upon the amount of brain damage. Aphasia affects one or more of a person's language functions. These could include speech, naming, repetition, hearing comprehension, reading, and writing. The functions affected depend upon the type of aphasia an individual has. For example, people with Broca's aphasia may not be able to speak at all. Or they may be able to use single-word statements or full sentences after great effort. They frequently omit words that are conjunctions and articles (and, or, but, the, a), which results in speech that sounds abrupt and choppy. People with Broca's aphasia can understand and process what others are saying, so they often become depressed and frustrated by their own inability to communicate. They may have difficulty reading, and weakness on the right side of the body may make writing difficult. Broca's aphasia is also called motor aphasia.
People with Wernicke's aphasia speak in long, run-on sentences that include words that aren't needed, difficult to understand, or simply made up. These patients are completely unaware of their language difficulties, and may not even understand what other people say at all. While they may still be able to write, what they write may not be understandable. People with Wernicke's aphasia also have difficulty reading. Because global aphasia affects more than one area of the brain, it can affect all language areas, and is the most severe form of aphasia. However, symptoms vary depending on the location and extent of injury.
There are three types of transcortical aphasia: transcortical motor aphasia, transcortical sensory aphasia, and mixed transcortical aphasia. People with transcortical aphasia suffer partial or total loss of the ability to communicate verbally or use written words, but can still repeat words, phrases, or sentences. Subcortical aphasia results in either the partial or total loss of the ability to speak or use written words. It is typical of a person who has had a stroke or other injury to the brain to have difficulty naming people or objects. This is called anomic or nominal aphasia. The patient might describe the object or person instead of naming it. All other language functions are unaffected. People with conduction, or associative, aphasia cannot repeat words, sentences, and phrases. While they can understand what others say, they may have difficulty finding the right words when speaking, and so may correct themselves frequently and skip or repeat words. Conduction aphasia is uncommon. Aphasia is rare in children, but the symptoms can begin with speech delays and progress to the loss of communication skills in all areas.
How is it diagnosed?
Anyone who has suffered a stroke or any type of brain injury is assessed for any effects on language skills. The doctor will listen to the patient speak, and ask him or her to identify and name common objects, repeat words or phrases, and demonstrate understanding of things that are said. It is important to determine whether the patient is having difficulty with speaking or difficulty with understanding. The patient will also be asked to write down some thoughts to assess written language skills. Standardized tests, administered by a speech pathologist or neuropsychologist, are often used in the diagnosis. These tests might include the Boston Diagnostic Aphasia Examination, the Western Aphasia Battery, and the Porch Index of Speech Ability. Test results are used to pinpoint the area of the brain that has been injured and to develop a speech therapy program best suited to the patient. Magnetic resonance imaging (MRI) and computed tomography scans (CT) are also helpful in mapping the area of the brain that is affected and to diagnose a brain tumor.
What is the treatment?
The primary treatment for most causes of aphasia is speech therapy, which is begun as soon as the patient's condition allows. There are no drugs available to cure or treat aphasia. The speech therapist works with the patient to strengthen his or her remaining language skills and to find ways to compensate for the skills that have been lost. Techniques might include exercising the facial muscles, repetition of words, using flash cards to improve memory of object names, using pictures of objects and activities to communicate with others, completing reading and writing exercises in workbooks, and using computer programs to aid in speech, hearing, and reading comprehension, as well as recall. Recovery from aphasia depends upon the severity of the brain injury. More than half of the patients who have symptoms of aphasia after a stroke, infection, head injury, or as a result of a brain tumor will recover. While people who are left handed are more likely to develop aphasia after a brain injury, they tend to recover more fully. This is because they have language centers on the right and left side of the brain so language abilities can be recovered from either side. Surgery is only used to treat the cause of aphasia, such as to reduce pressure from a brain tumor or to reduce swelling from head trauma.
Self-care tips
The types of events that cause aphasia, such as stroke and head injury, are difficult to predict or prevent. For this reason, there are no guidelines for preventing aphasia. However, individual and family commitment to a physician-guided speech therapy program can result in full to partial recovery.