Aphasia – Causes, symptoms and treatment



Aphasia is a loss of the ability to use and understand language. It results from damage to the part of the brain that is associated with language. The most common cause of aphasia is stroke.

Aphasia may be classified in several ways. When people with brain damage forget words and experience difficulty communicating with others, they have expressive aphasia. Aphasia characterized by problems understanding spoken or written words is called receptive aphasia. Receptive and expressive aphasia often occur simultaneously.

Some physicians also describe aphasia as either fluent or non-fluent. Aphasia is considered fluent if the patient is able to speak at a volume, speed and intonation that is similar to normal speech. If the patient has problems producing sentences or words, the aphasia is considered non-fluent.

Aphasia can be further categorized according to the location of damage in the brain:

  • Broca’s aphasia. Caused by damage to the frontal lobe of the brain and results in a highly simplified language system that is reliant on interpretation by the listener.

  • Wernicke’s aphasia. Caused by damage to the temporal lobe of the brain and results in the patient using nonsense words in fluent-sounding sentences.

  • Global aphasia. Caused by damage to various parts of the brain and may result in severe difficulties speaking and understanding words.

Often mistaken for aphasia, apraxia (loss of motor function, particularly in the mouth and tongue) is another symptom of brain damage that may accompany aphasia. People with aphasia may also experience depression, paralysis and memory loss.

Although the most common cause of aphasia is stroke, it may also be caused by other conditions, such as:

  • Alzheimer’s disease
  • Traumatic brain injury
  • Brain tumors or lesions
  • Landau-Kleffner syndrome

Treatment of aphasia typically focuses on rehabilitation of the patient’s language ability through individual or group therapy with a speech-language therapist. Although prevention of aphasia may not always be possible, taking measures to reduce the risk of stroke may be the most effective way to prevent aphasia.

Aphasia can make simple attempts to communicate difficult. There are certain steps that people with aphasia can take to ease their ability to communicate, such as carrying a pen and paper with them at all times. It is important for friends and family members of individuals with aphasia to remain patient and supportive. Research into potential treatment for aphasia is ongoing.

About aphasia

Aphasia is a loss of the ability to use and understand language. It is not a disease, but a symptom of brain damage. Aphasia can result from any type of injury to the part of the brain associated with language. For most people, this involves damage to the left side of the brain.

Some individuals with aphasia have problems understanding the language of other people. This is called receptive aphasia. Others have problems communicating with people. This is called expressive aphasia. It is also common for people to have both receptive and expressive aphasia. Most people with aphasia also have problems reading and writing.

There is no one language center in the brain. Instead, several large networks of neurons (nerve cells) connect the parts of the brain that are associated with hearing, understanding and producing language. Damage to any part of the neuron networks or the areas of the brain they connect may result in varying degrees and types of aphasia.

An estimated 1 million Americans currently have aphasia, according to the National Institute of Neurological Disorders and Stroke (NINDS). The National Institute on Deafness and Other Communication Disorders estimates that an additional 80,000 people in the United States develop aphasia each year.

The extent of aphasia ranges from mild to severe, depending on the location of the brain injury and the education and health status of the patient. People with mild aphasia may be able to communicate with others or carry on a conversation, but may have trouble following complicated discourse. People with severe aphasia may be unable to say or understand anything. Aphasia does not cause intellectual deficiencies. People with aphasia can think and reason to the same capacity as before the aphasia occurred.

Aphasia rarely affects infants or young children who have not yet developed language skills. This is because aphasia is the result of damage to areas of the brain associated with previously learned language. A rare epilepsy syndrome called Landau-Kleffner syndrome may cause aphasia in children who have already developed language skills. Parents of children who experience problems understanding or using language should consult a pediatrician, who can test for signs of other potential language disorders.

Aphasia may sometimes be confused with dysarthria (muscle weakness that impacts ability to speak). People with dysarthria have trouble articulating words because of damage to parts of the nervous system associated with the mechanics of speech. Their speech may be slurred or they may have consistent problems with pronunciation. However, unlike aphasia, people with dysarthria have no problem understanding language.

Aphasia may also sometimes be confused with verbal apraxia (speech impairment due to a loss of motor function). However, verbal apraxia involves impaired motor functioning (e.g., inability to properly move the tongue to form words) rather than brain damage.

Most cases of aphasia occur suddenly. However, in some people, aphasia develops gradually over time. People who experience aphasia should consult a physician as soon as possible as it may be an indication of a serious medical condition (e.g., stroke, brain tumor, Alzheimer’s disease).

Other symptoms related to aphasia

People who experience aphasia may also develop symptoms due to frustration that results from their inability to adequately communicate. Such symptoms may include confusion, disorientation and depression. These symptoms may be more likely to occur among patients who do not live in a supportive environment or who do not interact with people who understand how to communicate with someone experiencing aphasia.

Additional symptoms that may accompany aphasia include:

  • Verbal apraxia. A loss of motor functioning that can impact a person’s ability to speak. In addition to accompanying aphasia, verbal apraxia can sometimes mask the presence of the symptom.
  • Dysarthria. Muscle weakness that impacts ability to speak. People with dysarthria may have slurred speech or problems pronouncing certain sounds.
  • Memory loss. Aphasia that is caused by Alzheimer’s disease or a traumatic head injury may be accompanied by some degree of memory loss. This may be temporary, permanent or degenerative.
  • Impaired movement. Several symptoms relating to impaired movement or loss of movement may also occur with aphasia. For example, apraxia (the inability to perform purposeful movements) and ataxia (loss of coordination) may be caused by damage to the parts of the brain that can also cause aphasia. Problems with movement are especially likely to occur when aphasia is caused by widespread damage to the brain (e.g., due to stroke or head injury). For example, people who sustain frontal lobe damage may experience aphasia and paralysis of one side of their body.

Types and differences of aphasia

Aphasia can generally be described as expressive or receptive. People with expressive aphasia have difficulty speaking with others, whereas people with receptive aphasia have difficulty understanding written or oral communication. Expressive and receptive aphasia often occur simultaneously.

Some physicians may also describe aphasia as either fluent or non-fluent. Aphasia may be described as fluent if the patient is able to speak at a volume, speed and intonation that is similar to normal speech. If the patient has problems producing sentences or words, the aphasia may be described as non-fluent.

Aphasia may be further categorized according to the area of the brain that is damaged, such as:

  • Broca’s aphasia. Caused by damage to a part of the frontal lobe called Broca’s area. People with Broca’s aphasia may retain certain language skills, but are unable to speak in complete sentences or express complex thoughts. Thus, it may be considered a type of non-fluent aphasia. People with Broca’s aphasia often omit small words that connect larger thoughts, such as “and,” “is” or “the.” For example, “Go store” could mean “I want to go to the store,” “You need to go to the store” or “Jimmy will go to the store.”

    Broca’s aphasia tends to be expressive rather than receptive, which means that people with Broca’s aphasia may be able to understand language much better than they can express themselves with it. People with Broca’s aphasia may also have weakness or paralysis on the right side of their body because the frontal lobe is also associated with body movement. Broca’s aphasia is also sometimes referred to as motor aphasia or anterior aphasia.

  • Wernicke’s aphasia. Caused by damage to a part of the temporal lobe called Wernicke’s area. People with Wernicke’s aphasia tend to speak in long, fluent sentences, but may use nonsense words interspersed with real words. Thus, Wernicke’s aphasia may also be considered a type of expressive aphasia. People with this type of aphasia may produce sentences such as “I wanted to walk the weedle but didn’t like before.”

    Unlike people with Broca’s aphasia, people with Wernicke’s aphasia also often have difficulty understanding the speech of other people (receptive aphasia), and may be unaware of their own speech problems. There is usually no body weakness in people with this type of aphasia. Wernicke’s aphasia is also sometimes referred to as sensory aphasia or posterior aphasia.

Patients may have some but not all elements of either Broca’s aphasia or Wernicke’s aphasia. Some patients may have certain elements of both types.

Additionally, aphasia may be described as mild or severe. A mild form of aphasia is amnesia aphasia (also known as anomic aphasia). People with this type of aphasia may have difficulty remembering the correct words for certain objects, although they recognize and understand what the object is. This type of aphasia is common, especially in the early stages of Alzheimer’s disease and following head trauma.

The most severe form of aphasia is global aphasia, which may occur after damage to several parts of the brain associated with language. This typically involves a loss of almost all language function. It includes receptive and expressive aphasia. Global aphasia also involves difficulty with written communication (both reading and writing).

Potential causes of aphasia

Aphasia can be caused by anything that disrupts or damages the part of the brain associated with language. Conditions that may cause aphasia include:

  • Stroke. A life-threatening event in which part of the brain is deprived of adequate oxygen (hypoxia). Also known as a cerebrovascular accident (CVA) or a “brain attack,” a stroke occurs when a blood vessel in the brain bursts or becomes clogged by a blood clot or other mass. This prevents oxygen and nutrients from reaching nerve cells in the affected area of the brain. These nerve cells can die within minutes, and the area of the body that they control can cease to function. Stroke is the most common cause of aphasia.

  • Transient ischemic attack (TIA). A mini-stroke caused by a brief and temporary loss of blood supply to the brain. Although TIAs may result in similar symptoms to a stroke, they last for a short period of time (usually between one and 24 hours) before resolving themselves. TIAs are rarely life-threatening. However, they may be an indication that a person is at risk for a stroke and should be treated as a medical emergency.

  • Dementia. A collection of symptoms including memory loss, behavioral changes and language difficulties. Dementia syndromes that result from damage to the cerebral cortex (such as Alzheimer’s disease and Creutzfeldt-Jakob disease) are more likely to cause aphasia.

  • Head injury. Aphasia may occur if a traumatic head injury damages the part of the brain that is associated with language.

  • Brain tumor or lesion. Tumors or brain lesions, which can cause pressure to build in the brain, can disrupt the function of neurons in the brain. This can lead to aphasia, which may occur suddenly or gradually.

  • Schilder’s disease. A type of multiple sclerosis (MS) that develops during childhood. Schilder’s disease is a progressive disorder, although, like many forms of MS, it may go through periods of remission. This disease may cause aphasia in addition to symptoms such as personality changes, seizures and tremors.

  • Primary progressive aphasia (PPA). A type of dementia that involves the slow degeneration of cells in the areas of the brain associated with language. It is not the same as Alzheimer’s disease, which is more prevalent in people over 65 (although people with Alzheimer’s disease sometimes also develop PPA). The symptoms of PPA usually start when a person is around 50 years old. Unlike sudden-onset aphasia, PPA may cause damage to other areas of the brain as the brain cells continue to degenerate.

  • Landau-Kleffner syndrome. An extremely rare epileptic disorder in children, which may or may not involve seizures. It is also called acquired epileptic aphasia. Children with Landau-Kleffner syndrome may develop normal language skills and then suddenly lose them for no apparent reason. Although seizures (if they are present) often disappear by adulthood, children with Landau-Kleffner syndrome may have difficulty recovering their lost language skills.
  • Infections. Infections that affect the brain, such as meningitis and encephalitis, may cause aphasia. Aphasia caused by infection may develop gradually, depending on the severity and location of the infection. In many cases, aphasia may go away following treatment of the infection. However, sometimes the damage to the brain (and any resulting aphasia) may be permanent.

Diagnosing causes of aphasia

Diagnosing the cause of aphasia usually begins with a medical history and a physical examination. Sometimes the cause of aphasia is obvious and may be diagnosed before aphasia is noticed. This may be the case with severe head injury or stroke. However, sometimes a physician may need to conduct diagnostic tests to identify the cause of aphasia. These tests may include:

  • Imaging tests. Various imaging tests, such as computed axial tomography (CAT) scans and magnetic resonance imaging (MRI), can be used to diagnose problems with the brain. These tests can help identify common causes of aphasia, such as stroke and damage to the brain from a head injury.
  • Electroencephalogram (EEG). During this painless test, small electrodes are attached to the scalp. The electrodes are connected by wires (leads) to an electroencephalograph machine that charts the electrical activity of the brain.

  • Blood tests, including a complete blood count (CBC) and a lipid profile (cholesterol test). Blood tests may be useful in determining whether the patient has a high risk of stroke. High cholesterol, for example, may lead to mini-strokes, which can cause aphasia.

  • Evoked-potential study. The brain’s response to sight, hearing and touch are tested and measured to reveal any other neurological damage that may have occurred.

Treatment options for aphasia

In some cases, aphasia resolves on its own. This is especially common in aphasia that follows a transient ischemic attack, which is a mini-stroke where blood supply is cut off from the brain for a brief period of time before it is restored. In other cases, the aphasia may be long-lasting or permanent.

Aphasia can sometimes be eliminated by treating its underlying cause. This may involve surgery to remove brain tumors or to repair damage caused by a head injury.

Most often, treatment is aimed at rehabilitating patients and recovering their language abilities. Although lost language abilities are not always fully restored, patients may learn to use their remaining language abilities or compensate for lost abilities through new ways of communicating. Speech therapy, physical therapy, occupational therapy and psychological counseling may be recommended. Patients may be asked to engage in certain types of exercises that include reading, writing, following directions and repeating words or sentences.

Group therapy is commonly recommended for people who experience aphasia. This provides patients with an opportunity to socialize and practice communication skills in a safe and supportive environment. Group therapy may also be useful for the family and friends of people experiencing aphasia. It can offer them communication strategies and allow them to discuss their feelings and concerns.

The expected level of improvement depends on many factors, including the cause, extent and location of brain damage and a patient’s motivation level, as well as a patient’s age and general health. In general, a patient’s receptive abilities (to understand communication) may be more completely recovered than a patient’s expressive abilities (to speak). Treatment is more successful if it is started as soon as possible after the onset of aphasia, and is tailored to an individual’s specific needs.

For most people, the recovery process can take up to two years, after which time patients may or may not have recovered complete control of their language skills.

Prevention methods for aphasia

Because most cases of aphasia are caused by stroke, the most effective way of preventing aphasia may be to protect the body against stroke. Prevention methods for stroke may include:

  • Controlling high blood pressure (hypertension). Blood pressure abnormalities must be continually monitored and controlled because they are a chief contributor to strokes.

  • Refraining from or quitting smoking. The risk of stroke begins to decrease a few years after a person quits smoking.

  • Getting treatment for atrial fibrillation (abnormal heart rhythm) or atrial flutter.

  • Getting treatment for sleep apnea.

  • Learning stress management techniques and seeking help for depression or drug abuse. Cocaine, especially, has been linked to hemorrhagic stroke.

  • Reducing cholesterol levels, perhaps by taking cholesterol-reducing drugs.

  • Increasing one’s level of exercise. The U.S. surgeon general recommends that adults participate in moderate physical activity for at least 30 minutes on most days of the week.

  • Maintaining an ideal weight.

  • Limiting use of alcohol to about one glass of wine or one beer per day.

  • Controlling diabetes (a disorder in which the body is unable to produce or properly use the hormone insulin).

  • Eating a heart-healthy diet.

People can also reduce their risk of head injury, which can cause aphasia, by wearing a seatbelt while traveling in a car and wearing protective head gear when appropriate (e.g., while bicycling, rollerblading, playing contact sports).

Many other causes of aphasia (e.g., dementia, Alzheimer’s disease, brain tumor) may not be prevented.

Strategies for communication

Aphasia can make simple attempts to communicate difficult. People with aphasia may wish to carry a card that explains that they experience aphasia and what specific communication problems they have. People who experience aphasia may also benefit from keeping paper and a pen or pencil handy in order to better communicate with others.

Family support is an especially important part of aphasia treatment. It is important that family and friends of people with aphasia understand that the patient should be treated as a valuable member of the family or social group, and that the patient’s opinions are asked for and listened to. There are several communication strategies that family and friends can utilize to ease communication and reduce frustration. These strategies include:

  • Modify language. It is important that people realize that a person with aphasia has the capacity to think and reason normally. Communication may be eased if key words are emphasized and spoken clearly and sentences are simple and short. Baby-talk should not be used as this can belittle and humiliate the patient. In addition, unless a patient with aphasia is also experiencing hearing loss, it is important to speak at a normal volume.

  • Encourage communication. Patients experiencing aphasia should be allowed adequate time to talk. Family and friends should be patient while listening, and resist the urge to correct the patient’s speech.

  • Use alternate modes of communication. The use of visual cues, such as pictures of friends, family, food or other common items, may be useful in communication. People communicating with someone with aphasia should accept the validity of any form of communication, including written notes, hand gestures or intonation.

  • Establish the right environment for communication. In the early stages of recovery from aphasia, patients may find it overwhelming to attempt to communicate with more than one person. Therefore, communication should be conducted one-on-one. Additionally, the area that communication takes place in should be quiet, well-lit and free of excess stimuli to enable both parties to understand each other as well as possible.

  • Encourage involvement outside the home. Joining a support group can be valuable for both the patient and the patient’s family and friends. It may be an opportunity to meet people who are experiencing similar problems and can provide support and advice. It may also allow people with aphasia to practice communicating in a non-judgmental environment.

Ongoing research regarding aphasia

Much of the research concerning aphasia is focused on potential treatment and coping methods for long-lasting and permanent cases of aphasia. The possibility of treating aphasia with drug therapy has been studied for many years. It is thought that increasing levels of the neurotransmitter dopamine may help improve communication function in some people with aphasia. This may be effective when used in conjunction with speech and language therapy. In addition, certain medications are being studied for their potential to reduce the severity of aphasia when administered shortly after some types of stroke.

Research is also being performed to measure the effectiveness of computer-assisted therapy in people with aphasia. Special computer software may help people to improve reading, writing and oral comprehension skills of individuals with aphasia.  

Scientists are also trying to improve their understanding of how aphasia is caused in order to develop more accurate diagnostic methods. This, in turn, may help physicians to better plan treatment.

Questions for your doctor regarding aphasia

Preparing questions in advance can help patients and their caregivers to have more meaningful discussions with healthcare professionals regarding their condition. Patients or their caregivers may wish to ask their doctor the following aphasia-related questions:

  1. What caused my love one’s aphasia?
  2. What type of aphasia does my loved one have?
  3. Has my loved one sustained any other brain damage?
  4. Will my loved one ever regain full control of language skills, and if so, how long do you anticipate it will take?
  5. Can you recommend a speech-language therapist?
  6. Would group therapy be helpful for my loved one? How do I go about finding an appropriate group?
  7. Can you recommend a support group for friends and family of people with aphasia?
  8. Can you recommend strategies to communicate with my loved one?
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