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.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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