What Is Aphasia?


Aphasia is when an individual has difficulty with their language or speech. Aphasia is caused by damage to specific regions in the brain responsible for language, typically the left hemisphere. The two brain regions associated with aphasia due to their direct involvement in language are Broca’s area and Wernicke’s area. Aphasia can occur suddenly, often following a stroke or traumatic head injury, or it may develop slowly following a brain tumour or progressive neurological disease. Aphasia is specific to the individual and affects everyone differently. Aphasia can affect people of any age, however is most common in those over the age of 65 due to strokes and neurological conditions most likely to affect older individuals.1

Types of aphasia

Aphasia is often classified as either fluent aphasia or non-fluent aphasia, depending on the brain region damaged and consequently whether there are difficulties with understanding or expressing language, or both. 

Fluent aphasia (Wernicke’s aphasia)

Fluent aphasia is associated with damage to Wernicke’s area. Individuals with this type of aphasia can typically speak well and in full and complex sentences, but what they say may not make logical sense. Fluent aphasia is also sometimes referred to as receptive aphasia.

Non-fluent aphasia (Broca’s aphasia)

Non-fluent aphasia is associated with damage to Broca’s area. Individuals with this type of aphasia experience difficulty communicating their thoughts, ideas and feelings with others despite likely knowing exactly what they want to say. Non-fluent aphasia is also sometimes referred to as expressive aphasia.

Mixed non-fluent aphasia

Individuals with mixed non-fluent aphasia resemble those with severe Broca’s aphasia, however unlike with Broca’s aphasia remain limited in their comprehension of speech. 

Anomic aphasia

Anomic aphasia is a milder form of aphasia. With anomic aphasia, the individual can have difficulty supplying the word to specific things they wish to talk about, particularly significant nouns and verbs. Individuals with anomic aphasia typically have fluent and grammatically correct speech, but often use vague words (such as “thing”) and circumlocutions (where they attempt to describe the word they mean).

Primary progressive aphasia (PPA)

PPA is a rare type of dementia, caused by damage to the areas of the brain associated with language. PPA is a progressive condition, and language impairment worsens over time. Usually, the first problem individuals with PPA experience is difficulty finding the right word or remembering somebody’s name.

Global aphasia

Global aphasia is the most severe form of aphasia, and describes individuals who can produce very few recognisable words and understand little to no language. Individuals with global aphasia can neither read nor write.

Other types of aphasia

There are many aphasic deficits which do not fit a specific diagnosis as above but still cause significant language deficits following injury or damage to the brain.2

Causes of aphasia

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

  • Stroke
  • Traumatic brain injury
  • Brain tumour
  • Progressive neurological conditions - these are conditions which cause damage to the brain and nervous system over time, such as dementia1

Signs and symptoms of aphasia

Individuals with aphasia have trouble with the main ways people understand and use language, these are:

  • Reading
  • Writing
  • Speaking
  • Listening

Speaking problems are the most obvious symptom, and individuals with aphasia typically make mistakes with the words they use. This can involve using the wrong sound in a word, choosing the wrong word altogether or putting words together incorrectly so that a sentence does not make sense. Symptoms vary between each individual depending on the type of aphasia. Although aphasia results in communication deficits, it does not affect intelligence.

Aphasia may occur by itself, or alongside other disorders depending on the cause of the condition.1

Management and treatment for aphasia

The main treatment for aphasia is speech and language therapy. Speech and language therapy is carried out by a qualified speech and language therapist, and the aim of the treatment is to help restore as much speech and language as possible, help communication, find alternative methods of communication if necessary, and provide information and support to both the individual with aphasia and their family. 

The prognosis of aphasia with speech and language therapy depends on the underlying cause of aphasia, with the best prognosis being in the immediate few weeks and months following a stroke and the worst prognosis being for those with a progressive neurological condition.1

However, seeking support as early as possible will ensure a better quality of life for anyone suffering from aphasia and their support network.

Diagnosis of aphasia

Aphasia is diagnosed by qualified clinicians, typically involving doctors and speech and language therapists. A series of tests will be run to assess any language deficits and will typically involve tasks such as naming objects, repeating sentences and reading and writing. These tests are used to understand the individual’s ability to communicate, understand speech and grammar, express words/phrases/sentences, and read and write.

Sometimes, CT or MRI scans will be used to investigate any regions of brain damage.


How common is aphasia

Aphasia is common in those who have experienced a stroke, a traumatic brain injury or have a progressive neurological disease such as dementia. There are approximately 2,000,000 in the USA  and 250,000 in Great Britain that have aphasia.3

Can aphasia be prevented

There is no way of preventing aphasia. Lifestyle factors can contribute to the development of the underlying causes of aphasia, such as progressive neurological disease, and so lifestyle changes may help reduce the risk of these diseases and thus aphasia. 

Who are at risk of aphasia

Aphasia is most common in older people over the age of 65, however, it can occur in people of all ages, genders, races and nationalities. 

When should I see a doctor

If you or anyone you know is suffering from signs of aphasia, medical attention should be sought immediately. 


Aphasia can be frustrating and difficult for the individual and their family and friends, however, with the early intervention and speech and language therapy it is manageable. While there is no cure for aphasia, communication can be drastically improved. 


  1. Aphasia. NHS. https://www.nhs.uk/conditions/aphasia/ (accessed 7th April, 2023).
  2. Aphasia definitions. National Aphasia Association. https://www.aphasia.org/aphasia-definitions/ (accessed 7th April, 2023).
  3. Aphasia statistics. National Aphasia Association. https://www.aphasia.org/aphasia-resources/aphasia-statistics/ (accessed 7th April, 2023).
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Amy Louise Bowler

Current Master of Science student – MSc Clinical Neuroscience at University College London (UCL)

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