Content Supplied by NHS Choices


Aphasia is a communication disorder which makes it difficult to read, write or speak.

Aphasia is a condition that affects the brain and leads to problems using language correctly.

People with aphasia make mistakes in the words they use, sometimes using the wrong sounds in a word, choosing the wrong word, or putting words together incorrectly.

Aphasia also affects speaking and writing in the same way. Many people with the condition find it difficult to understand words and sentences they hear or read.

Why does aphasia happen?

Aphasia is caused by damage to parts of the brain responsible for understanding and using language. Common causes include:

  • stroke, thought to be the most common cause, around one in three people experience some degree of aphasia after having a stroke
  • severe head injury
  • brain tumour
  • progressive neurological conditions (conditions that over time cause progressive brain and nervous system damage, such as Alzheimer’s disease)

Read more about the causes of aphasia.

Types of aphasia

Some more common types of aphasia are:

  • Broca's aphasia
  • Wernicke's aphasia
  • global aphasia
  • aphasia in Alzheimer's disease
  • primary progressive aphasia (PPA)

These are described below.

Broca's aphasia

In Broca's aphasia, also known as non-fluent or expressive aphasia, a person has great difficulty speaking and can only manage to string a small number of words together in short, halting sentences. However, it is usually possible to understand the meaning of their speech. For example, a person with Broca's aphasia might say, " no...milk".

Wernicke's aphasia

In Wernicke's aphasia, also known as fluent aphasia, a person is able to speak normally and use long, complex sentences, but the actual words they use do not make sense, or they include nonsense words in their speech.

Many people with Wernicke's aphasia are often unaware their spoken language makes no sense to others and can become angry or frustrated by the lack of understanding shown by others.

Global aphasia

Global aphasia is a severe form of aphasia. Someone with the condition has difficulty with all forms of communication, including speaking, reading, writing, correctly naming objects or people, and understanding other people’s speech.

Aphasia in Alzheimer's disease

People with Alzheimer's disease usually have trouble thinking of the right word, or remembering people's names. This is called anomia or anomic aphasia. As the condition gets worse, people may have difficulty putting a sentence together and making themselves understood. People usually develop problems with memory and understanding at the same time, which can also make communication more difficult.

Primary progressive aphasia

Sometimes a progressive brain disease causes aphasia but doesn't affect memory or other thought processes for a long time, possibly for several years. This is called primary progressive aphasia (PPA).

Read more about the symptoms of aphasia.

How is aphasia treated? 

A speech and language therapist (SLT) usually diagnoses the condition by testing your language capabilities. They can also help arrange treatment.

Speech and language therapy is the main type of treatment for people with aphasia. This aims to help restore some of your ability to communicate and also help you develop alternative ways of communicating, if necessary.

The effectiveness of treatment is different for everyone, but most people with aphasia make at least some degree of recovery and some recover fully. Even if aphasia persists, it does not necessarily mean a person is unable to live an independent and meaningful life.

However, the chances of recovery for people with aphasia related to progressive neurological conditions is poor because there is no way of repairing or preventing the ongoing injury to the brain associated with these types of conditions.

When aphasia is caused by a progressive condition, treatment focuses on making the most of what people can still do, and on developing other ways of communicating, to prepare for a time when speaking will be more difficult.

Read more about diagnosing aphasia and treating aphasia.


Due to the challenges of living with aphasia, some people with the condition develop further problems.

People may experience what are sometimes called "catastrophic reactions". These are sudden and overwhelming outbursts of frustration and anxiety, often in the form of aggression or screaming. However, these reactions are only temporary and should pass.

Losing the ability to communicate effectively can understandably also lead to depression in many people with aphasia. Discussing feelings openly or taking medication can be helpful in managing this.

Read more about complications of aphasia.

Content Supplied by NHS Choices


The main sign of aphasia is difficulty with communication, although the condition affects everyone differently.

The main sign of aphasia is difficulty with communication, although the condition affects everyone differently.

In cases where aphasia has been caused by a sudden brain injury, such as a stroke or a severe head injury, symptoms will usually develop straight after the injury.

In cases where there is gradual damage to the brain as a result of a condition that gets worse over time, such as dementia or a brain tumour, the symptoms may develop gradually.

Broca's aphasia

Someone with Broca's aphasia will usually have the following signs and symptoms:

  • slow and halting speech
  • they may struggle to get certain words out, such as the names of objects, places or people
  • the content of their speech is usually stripped down to simple elements and only contains basic nouns and verbs, for example, "want drink" or "go town today"
  • their writing ability is often similarly affected

A person with Broca's aphasia may be able to understand spoken language to some degree, but have difficulty understanding grammar. For example, they may be unable to tell the difference in meaning between, "Maureen slapped the naughty boy" and "the naughty boy slapped Maureen."

Their ability to read is usually affected. For example, they may assign different meanings to written words, such as reading ‘symphony’ when the word is actually ‘concert’. They may also lose the ability to sound out written words in their head.

Additional symptoms not directly connected to speech and language but which can occur in people with Broca's aphasia include:

  • an inability to control facial muscles and limbs
  • weakness down one side of their body (usually the right side)

Wernicke's aphasia

A person with Wernicke's aphasia will usually have the following signs and symptoms:

  • They may be able to speak fluently using long sentences, but their speech lacks meaning and often includes nonsense words. For example, they might say “That was just like time for the next week when the bait”. The same difficulty may also occur when they write.
  • They may have difficulty understanding what people say, and what written words mean.
  • They often don't realise that they have difficulty understanding, and don't know why people can't understand them. This is especially true during the initial stages of the condition, and can be frustrating for them.

Additional symptoms can include:

  • some loss of vision
  • difficulties with arithmetic, such as adding, subtracting, multiplying or dividing numbers
  • difficulties with spatial orientation, which is the ability to judge accurately where you are in relation to other objects
  • loss of voluntary limb control

Global aphasia

People with global aphasia have symptoms of both Broca’s aphasia and Wernicke’s aphasia. This can cause severe problems with all aspects of communication, as they have great difficulty with speaking, understanding, reading and writing.

Additional symptoms can include:

  • paralysis of the right side of the body
  • some loss of vision
  • loss of voluntary control of their limbs
  • problems pronouncing certain sounds and words due to difficulties controlling the mouth, tongue and voice box

Primary progressive aphasia

The first problem that people with primary progressive aphasia (PPA) usually notice is difficulty finding the right word or remembering somebody's name. Gradually the problems get worse, and there are three main ways in which this can happen:

  • Speaking becomes hesitant and effortful, and the person makes mistakes in the sounds of words and in grammar.
  • Speaking becomes slow, with short, simple sentences.
  • The person forgets the meaning of complicated words, and later also simple ones, making it more difficult for them to understand other people. Speaking remains easy but they become increasingly vague and general in what they say.

A person with PPA may also experience other symptoms later in their illness, including changes in their personality and behaviour, difficulties with memory and thinking similar to Alzheimer's disease, or difficulties with movement similar to Parkinson's disease.

Content Supplied by NHS Choices


Aphasia is the result of damage to the parts of the brain that are responsible for speaking, reading, writing and understanding others.

Aphasia is the result of damage to the parts of the brain involved in speaking, reading, writing and understanding others.

Collectively, these parts of the brain are known as the brain’s language centre.

The language centre

The language centre is not a single area of the brain. It is a network of specific sections of the brain that work together.

The language centre is made up of:

  • Broca’s area, involved with the production of speech
  • Wernicke's area, involved with understanding spoken and written language
  • the sensory cortex, involved with processing the various signals the body receives, such as sounds (for language) and images (for reading)
  • the auditory cortex, involved with converting the actual physical sounds of spoken language into meaningful information
  • the motor cortex, involved with controlling various parts of the body used to generate speech, including the tongue and voice box

In the past, it was thought damage to a specific part of the brain would always result in a specific type of aphasia, for example, damage to the Broca’s area would always result in Broca’s aphasia. However, the way the language centre works is now thought to be less straightforward than this.

Damage to specific areas of the language centre does not always lead to the expected symptoms. Also, the after effects of brain damage can vary considerably from person to person, making them unpredictable.

Damage to many sections of the brain will usually result in more severe types of aphasia, such as global aphasia.

Brain damage

Ways that the brain can become damaged include the following:

  • stroke: during a stroke the brain is deprived of blood and oxygen, which leads to the death of brain tissue
  • severe head injury: for example, the sort of injury that occurs as a result of a road traffic accident or following a serious fall from height
  • brain tumour: where an abnormal growth of cells develops inside the brain
  • health conditions that cause progressive loss of cells from the brain, such as Alzheimer’s disease. Parkinson's disease does not cause aphasia, but some very similar conditions may do so, such as progressive supranuclear palsy (PSP) or corticobasal degeneration (CBD)
  • infections that affect the brain, such as meningitis (an infection of the outer layer of the brain) and encephalitis (an infection of the brain itself), although this is a much rarer cause of aphasia

Content Supplied by NHS Choices


Aphasia is usually diagnosed after tests carried out by a specialist called a speech and language therapist.

Aphasia is usually diagnosed after tests carried out by a specialist called a speech and language therapist.

Communication assessment

There are several tests used to assess an individual’s communication skills.

These tests often involve simple exercises, such as asking a person to name as many words as they can think of beginning with the letter F, or asking them to name objects in the room. The results can then be used to build up a detailed picture of a person’s language capabilities.

Imaging scans

Imaging techniques can be used to assess the extent of any brain damage. The two most widely used types of imaging in diagnosing aphasia are:

Less commonly, a type of scan known as a positron emission tomography (PET) scan may be used to assess the state and functionality of the brain. PET scans are usually only used to carry out clinical research at specialist centres.

A PET scan works by detecting energy produced by positrons (positively charged particles). This allows researchers to study a number of processes inside the brain, such as blood flow, inflammation, and the release of dopamine (a chemical associated with physical pleasure). Therefore, a PET scan can provide an insight into how the brain is functioning, as well as simply seeing what it looks like.

This type of information can be useful in diagnosing aphasia associated with progressive damage to the brain, such as damage caused by Alzheimer’s disease.

Content Supplied by NHS Choices


Sometimes aphasia will improve on its own without treatment, but a type of treatment called speech and language therapy is usually recommended.

Sometimes aphasia will improve on its own without treatment, but a type of treatment called speech and language therapy is usually recommended.

This treatment is carried out by a speech and language therapist (SLT). If you were admitted to hospital, there should be a speech and language therapy team there. 

If you weren't admitted to hospital or didn't see an SLT while you were there, you can ask your GP to refer you. In some areas you can contact your local speech and language therapy department directly.

For people with aphasia, speech and language therapy aims to:

  • help you communicate to the best of your ability 
  • help restore as much of your speech and language as possible
  • find alternative ways of communicating

Evidence suggests that speech and language therapy is more effective if it is started as soon as possible, as most people who make a recovery do so within six months. However, it is important to remember there can be improvements even after many years.

How the therapy is carried out will depend on your circumstances. If appropriate, an intensive course of speech and language therapy may be recommended as this can be more effective. This involves longer individual sessions spread out over a shorter period of time.

However, speech and language therapy can be exhausting and an intensive course of treatment will not be suitable for everyone. For some people, short but frequent sessions may be recommended to begin with.


The treatment you receive will depend on your general health and the difficulties you have with your speech, language or social skills, as there is no universally accepted treatment for aphasia. 

It is therefore important that an assessment is carried out before therapy begins so the therapist can identify your strengths and which aspects of language you have the most difficulty with.

The therapist will initially informally assess your language and communication by talking to you and your family. They will try to determine if your problems are related to understanding language or if you have problems expressing yourself.

The SLT should then carry out a formal assessment to focus on the areas that need to be targeted in therapy. Other health problems that may impact on your ability to communicate, such as hearing or sight problems, will also be taken into account.

After these assessments, your SLT will have a good idea of the extent of your communication difficulties and will start putting together a treatment plan.

Speech and language therapy techniques

The specific speech and language therapy techniques used and the aims of the treatment will depend on each person's circumstances. Some examples of the techniques that may be used are described below.

If you have difficulty understanding words, your SLT may ask you to carry out tasks such as matching words to pictures or sorting words by their meaning. The aim of these tasks is to improve your ability to remember meanings and link them with other words.

If you have difficulty expressing yourself, your SLT may ask you to practise naming pictures or judge whether certain words rhyme. They may also ask you to repeat words that they say, with prompting if necessary. If you are able to complete tasks with single words, your therapist will work on your ability to construct sentences.

Some techniques may involve working with a computer. Other methods may include group therapy with other people with aphasia, or working with family members. This will allow you to practise conversational skills, such as taking turns speaking, or rehearse common situations, such as making a telephone call. 

Alternative methods of communication

An important part of speech therapy is using your strengths to find different ways for you to communicate. Your therapist will help you develop alternatives to talking, such as using gesture, writing, drawing or communication charts.

Communication charts are large grids containing letters, words or pictures. They allow someone with aphasia to communicate by pointing at the word or letter to indicate what they want to say.

For some people, specially designed electronic devices, such as voice output communication aids (VOCAs), may be useful. VOCAs use a computer-generated voice to play messages aloud. This can help if you have difficulty speaking but you are able to write or type. There are also applications (apps) available on smartphones and computer tablets that can do this.

The funding available for alternative communication technologies such as VOCAs varies throughout the UK. Some local health or education authorities pay for them, but it may be necessary to buy the equipment yourself, fundraise or borrow equipment from a charity.

Communicating with a person with aphasia

If you live with or care for a person with aphasia, you may be unsure about the best way to communicate with them. You may find the following advice helpful:

  • After speaking, allow the person plenty of time to respond. If a person with aphasia feels rushed or pressured to speak, they may become anxious, which can affect their ability to communicate.
  • Use short, uncomplicated sentences and do not change the topic of conversation too quickly.
  • Avoid asking open-ended questions. Closed questions that have a yes or no answer can be better.
  • Avoid finishing a person's sentences or correcting any errors in their language. This may cause resentment and frustration for the person with aphasia.
  • Keep distractions to a minimum, such as background radio or TV noise.
  • Use paper and a pen to write down key words or draw diagrams or pictures to help reinforce your message and support their understanding.
  • If you do not understand something that a person with aphasia is trying to communicate, do not pretend you understand. The person may find this patronising and upsetting. 
  • Use visual references, such as pointing, gesture and using objects, to support their understanding.
  • If they are having difficulty finding the right word, prompt them – ask them to describe the word, think of a similar word, try to visualise it, think of the sound the word starts with, try to write the word, use gesture or point to an object.

Other treatments

Research is currently being carried out to study whether other treatments can benefit people with aphasia. These include:

  • medication – such as piracetam, bifemelane, piribedil, bromocriptine and idebenone
  • transcranial magnetic stimulation – where an electromagnet placed on the scalp is stimulated for a short time using an electric current to stimulate parts of the brain affected by aphasia

Although some studies have suggested these treatments may benefit some people with aphasia, further research is necessary. You can search the database of clinical trials for aphasia to find trials that are studying these treatments.

Content Supplied by NHS Choices


The challenges of living with aphasia can sometimes cause further problems.

The challenges of living with aphasia can sometimes cause further problems.

Catastrophic reactions

Many people with aphasia experience episodes of what is sometimes called a catastrophic reaction. This is where a person suddenly experiences overwhelming feelings of frustration, anger, depression or a general feeling that they cannot cope with their immediate situation.

Signs of a catastrophic reaction include:

  • anxiety
  • aggression
  • crying or laughing uncontrollably
  • screaming
  • stubbornness

A catastrophic reaction is often triggered when a person with aphasia becomes acutely aware of their communication difficulties. Therefore, it commonly occurs at the start of a course of speech and language therapy.

If someone in your care experiences a catastrophic reaction, you should remain as calm as possible and try to reassure them these feelings will pass and everything will be alright.


Because losing the ability to communicate can be a devastating experience, depression is a common complication of aphasia.

In addition, many conditions associated with aphasia, such as stroke or Alzheimer’s disease, may change the chemistry of a person’s brain, making them more vulnerable to depression.

Research suggests as many as eight out of 10 people with aphasia will experience at least one episode of depression.

Due to obvious communication problems, it may be difficult for someone with aphasia to let others know they are feeling depressed. Possible signs that a person with aphasia may be feeling depressed include:

  • lack of energy
  • little interest or enthusiasm in speech and language therapy
  • lack of appetite
  • weight loss
  • withdrawing from social contact with others
  • insomnia

If you are concerned someone you know with aphasia may be depressed, if possible, encourage them to communicate how they feel and whether they think they may benefit from treatment for depression. You should also make your concerns known to a member of their care team.

The types of anti-depressant known as selective serotonin reuptake inhibitors (SSRIs) have proved to be moderately effective in treating depression in people with aphasia.

Content Supplied by NHS Choices


As stroke is one of the main risk factors for developing aphasia, taking steps to prevent a stroke will in turn help reduce the risk of aphasia

There is no guaranteed method of preventing aphasia. However, there is some general lifestyle advice that can reduce your risk of developing conditions that are associated with aphasia, such as Alzheimer’s disease (or other forms of dementia) or stroke.

For example, you should:

  • stop smoking (if you smoke)
  • avoid drinking large amounts of alcohol
  • eat a healthy, balanced diet that includes at least five portions of fruit and vegetables every day
  • use a combination of exercise and a calorie controlled diet to achieve a healthy weight, which is particularly important if you are overweight or obese
  • exercise for at least 30 minutes each day because this will improve both your physical and mental health
  • stay mentally active, for example, by reading, writing or taking an adult education course

Below is a list of topics that provide more detailed information and advice about the conditions that are associated with aphasia.


Share this page