WHAT IS APHASIA?
What is Aphasia?
Aphasia is a communication disorder that results from damage or injury to language parts of the brain. About a third of all stroke case in the United States leads to Aphasia, and at least 2 million people in the USA have been diagnosed with Aphasia (1). Aphasia is more common in older adults, particularly those who have had a stroke (1).
Aphasia doesn’t impair the ability to think or a person’s intelligence, rather, people with Aphasia may have difficulty expressing their thoughts and struggle with understanding others. However, with treatment and practice, many people with Aphasia improve over time (1).
The symptoms of Aphasia can vary greatly depending on which area of the brain is damaged and how severe the damage is. Most people with Aphasia are aware that they are having trouble communicating. This can be frustrating for both people with Aphasia and their loved ones. Early diagnosis and treatment can help people with mild to moderate Aphasia regain some of their language abilities and learn new ways to communicate effectively (1).
Aphasia is not a disease but rather a symptom of underlying neurological conditions.
What Causes Aphasia?
In most cases, Aphasia result from damage to the parts of the brain responsible for language; usually in the left hemisphere or the areas that connect the two hemispheres of the brain. Damage can result from stroke, head injury, brain tumor, or infection.
Stroke: Most people with Aphasia have suffered a stroke. A stroke occurs when blood flow to the brain is blocked by a clot or by bleeding in the brain. The cells in the area of the brain deprived of oxygen begin to die within minutes causing damage to the part of the brain that controls language ability(2).
Brain tumor: Although not as common as strokes, brain tumors can also cause damage that leads to Aphasia. For example, tumors or swelling in areas of the brain that control language ability can cause symptoms similar to those caused by strokes(3).
Head injury: Damage to the language areas of the brain caused by an injury can result in Aphasia. Injury may cause sudden onset of symptoms or may lead to progressive decline over time, depending on the severity and location of the injury (4).
Aphasia may also sometimes occur with dementia, Alzheimer's disease, and progressive neurological disorders(3).
What Are the Types of Aphasia?
Global Aphasia
Global Aphasia is a communication disorder most commonly caused by a left hemisphere brain injury.
The disorder is characterized by severe deficits in language skills such as:
- speaking,
- listening,
- reading,
- writing.
The severity of the symptoms depends on the extent, location and cause of the injury to the brain.
People with Global Aphasia may have difficulty recognizing words or writing coherently. These individuals may be able to understand some simple gestures or phrases, but have much difficulty understanding longer sentences even if spoken slowly. They may be able to say individual words that are not meaningful or short phrases. Their ability to read or write is severely impaired (3).
Global Aphasia typically has one of two causes: stroke or traumatic brain injury (TBI). Individuals who have suffered strokes often experience mild aphasic symptoms for several days followed by worsening of symptoms over time. Patients with TBI often experience symptoms immediately after the injury occurs.
Expressive Aphasia
Expressive Aphasia is a language disorder that results from damage to the brain (specifically, Broca's area in the dominant hemisphere). It is also called non-fluent Aphasia or Broca's Aphasia(4).
Expressive Aphasia is characterized by an effortful and non-fluent speech output, meaning that the output of speech is slow, labored, and has frequent pauses between words. The individual typically knows what he/she wants to say but cannot get the words out. Fluency is not affected by expressive Aphasia. People with this type of Aphasia often have difficulty finding specific words even though they may be able to describe them. They can also repeat phrases (Aphasia) readily.
Other characteristics of expressive Aphasia include:
- Echolalia - the repetition of others' speech,
- Perseveration - repeating the same word or phrase over and over again,
- Paragrammatism - switching parts of speech inappropriately.
Wernicke's (Sensory) Aphasia
Wernicke's (sensory) Aphasia is a language disorder resulting from damage to Wernicke's area in the brain's left temporal lobe. It is characterized by fluent, but inconceivable speech. The patient will use made-up words, called neologisms, or words unrelated to the context of the conversation. In severe cases, patients may not be able to understand any spoken language and linguistic knowledge may not be preserved; for example, a patient with severe cases of this type of Aphasia cannot distinguish between voices based on pitch and tone alone(4).
The patient may also exhibit:
- Anomia (difficulty recalling names),
- Agraphia (difficulty writing) and,
- Acalculia (difficulty performing arithmetic).
How is Aphasia Diagnosed?
If your doctor suspects you have Aphasia, they will refer you to a speech-language pathologist for further tests. A speech-language pathologist is a professional who specializes in communication disorders, including Aphasia. He or she will ask the patient about their medical history and make observations during their conversation. The patient may be asked to name objects and talk about familiar topics, as well as follow requests and directions, read text, and write words or sentences.
A speech-language pathologist may administer other tests to determine the severity of language loss, identify strengths and weaknesses in language abilities, and predict the possibility of improvement with treatment (4). These tests may include:
- A written assessment of the patient’s reading comprehension skills,
- An oral assessment of the patient’s speaking abilities, a written assessment of the patient’s spelling abilities and,
- An oral assessment of the patient’s listening skills.
Tests that assess the severity of other problems often associated with Aphasia, such as memory difficulties or weakness on one side of the patient’s body may be provided. This information can provide additional information about the patient’s other cognitive needs.
How is Aphasia Treated?
People with Aphasia can often benefit from treatment to improve their communication skills. Speech-language pathologists, trained in treating people with speech and language disorders, provide treatment to help improve communication abilities (5).
Speech-language therapy programs typically include:
- Individualized training that builds on the person's strengths to improve language skills.
- The use of alternative methods of expression, such as gestures or drawing, when words fail.
- Treatment for family members and caregivers on how to support communication and manage frustration.
Treatment for Aphasia varies with each person. However, most people with Aphasia will benefit from therapy with a speech-language pathologist (6).
People who have suffered a stroke might benefit from rehabilitation in the hospital followed by further rehab in an outpatient setting. Rehabilitation may help improve some of the language skills lost due to the stroke and relearn how to perform daily tasks.
The goal of treatment is to help people with Aphasia communicate as effectively as possible. Speech and language therapy generally consists of three types of treatment (7):
- Restorative treatment: This type of treatment helps people relearn lost language skills by practicing different ways to express themselves, such as through gestures or writing.
- Compensatory treatment: This type of treatment teaches people new strategies or ways to communicate that they can use while they are recovering or relearning their language abilities, such as using word boards or picture cards to supplement speech.
- Maintenance treatment: This type of treatment helps people retain their improved communication skills over time by providing information about the disorder and ongoing practice using their new language skills on a daily.
The extent of recovery depends on the severity of the brain damage, the type of Aphasia, and how much time passes between the injury and treatment. In about half of all cases, symptoms improve with time and treatment. But in many cases, recovery stops after a year or two; full recovery rarely occurs after that (6).
Many people with Aphasia continue to make improve their communication abilities years after suffering an injury. This improvement often results from learning new ways to communicate or using different parts of their brains to process language (7).
Conclusion
Aphasia can occur at any age. It is most common in older adults, particularly those who have had a stroke. Aphasia can also occur in young people and children, especially if they have suffered some type of brain damage due to head trauma, stroke or tumor. From 2011 to 2012, among 152,972 adults who were hospitalized for a stroke in the eight representative states (Oregon, Arizona, Colorado, Florida, Kentucky, North Carolina, South Carolina, Arkansas), 28,086 (18.4%) of the patients discharged had Aphasia (8).
The study of Aphasia has long been of interest to neurologists, as it can be used to understand how language is represented in the brain. Areas of the brain involved with languages such as Broca's and Wernicke's have been studied extensively, especially since the advent of effective neuroimaging techniques such as functional magnetic resonance imaging (FMRI).
Recent research suggests that Aphasia may result from the failure of multiple speech-related circuits rather than one. Studies using transcranial magnetic stimulation (TMS) show that stimulating Broca's area alone does not produce any errors in repetition or naming tasks, but stimulating both at the same time produces errors in both tasks. This suggests that there are two circuits in the language system: one for speech production, and one for speech comprehension.
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