NIDCD...Improving the lives of people with communication disorders

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES ∙ National Institutes of Health

NIDCD Fact Sheet | Voice, Speech, and Language

Aphasia

What is aphasia? 

Aphasia is a disorder that results from damage to portions 

of the brain that are responsible for language. For most 

people, these areas are on the left side of the brain. 

Aphasia usually occurs suddenly, often following a stroke 

or head injury, but it may also develop slowly, as the result 

of a brain tumor or a progressive neurological disease. 

The disorder impairs the expression and understanding of 

language as well as reading and writing. Aphasia may cooccur with speech disorders, such as dysarthria or apraxia 

of speech, which also result from brain damage.

Who can acquire aphasia? 

Most people who have aphasia are middle-aged or older, 

but anyone can acquire it, including young children. 

About 1 million people in the United States currently have 

aphasia, and nearly 180,000 Americans acquire it each 

year, according to the National Aphasia Association.

What causes aphasia? 

Aphasia is caused by damage to one or more of the 

language areas of the brain. Most often, the cause of 

the brain injury is a stroke. A stroke occurs when a blood 

clot or a leaking or burst vessel cuts off blood flow to

part of the brain. Brain cells die when they do not receive 

their normal supply of blood, which carries oxygen and 

important nutrients. Other causes of brain injury are 

severe blows to the head, brain tumors, gunshot wounds, 

brain infections, and progressive neurological disorders, 

such as Alzheimer’s disease.

Areas of the brain affected by Broca’s 

and Wernicke’s aphasia

Front Left Side View Back

Broca Wernicke

What types of aphasia are there?

There are two broad categories of aphasia: fluent and

nonfluent, and there are several types within these groups.

Damage to the temporal lobe of the brain may result 

in Wernicke’s aphasia (see figure), the most common 

type of fluent aphasia. People with Wernicke’s aphasia 

may speak in long, complete sentences that have

no meaning, adding unnecessary words and even 

creating made-up words. 

For example, someone with Wernicke’s aphasia may say, 

“You know that smoodle pinkered and that I want to get 

him round and take care of him like you want before.” 

As a result, it is often difficult to follow what the person is 

trying to say. People with Wernicke’s aphasia are often 

unaware of their spoken mistakes. Another hallmark of 

this type of aphasia is difficulty understanding speech.
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The most common type of nonfluent aphasia is Broca’s 

aphasia (see figure on previous page). People with Broca’s 

aphasia have damage that primarily affects the frontal 

lobe of the brain. They often have right-sided weakness 

or paralysis of the arm and leg because the frontal lobe is 

also important for motor movements. People with Broca’s 

aphasia may understand speech and know what they 

want to say, but they frequently speak in short phrases 

that are produced with great effort. They often omit small 

words, such as “is,” “and” and “the.”

For example, a person with Broca’s aphasia may say, 

”Walk dog,” meaning, ”I will take the dog for a walk,” 

or ”book book two table,” for ”There are two books on 

the table.” People with Broca’s aphasia typically 

understand the speech of others fairly well. Because of 

this, they are often aware of their difficulties and can 

become easily frustrated.

Another type of aphasia, global aphasia, results from 

damage to extensive portions of the language areas of 

the brain. Individuals with global aphasia have severe 

communication difficulties and may be extremely limited 

in their ability to speak or comprehend language. They 

may be unable to say even a few words or may repeat 

the same words or phrases over and over again. They 

may have trouble understanding even simple words 

and sentences.

There are other types of aphasia, each of which results 

from damage to different language areas in the brain. 

Some people may have difficulty repeating words 

and sentences even though they understand them 

and can speak fluently (conduction aphasia). Others 

may have difficulty naming objects even though they 

know what the object is and what it may be used for 

(anomic aphasia). 

Sometimes, blood flow to the brain is temporarily 

interrupted and quickly restored. When this type of injury 

occurs, which is called a transient ischemic attack, 

language abilities may return in a few hours or days.

How is aphasia diagnosed? 

Aphasia is usually first recognized by the physician 

who treats the person for his or her brain injury. Most 

individuals will undergo a magnetic resonance imaging 

(MRI) or computed tomography (CT) scan to confirm 

the presence of a brain injury and to identify its precise 

location. The physician also typically tests the person’s 

ability to understand and produce language, such as 

following commands, answering questions, naming 

objects, and carrying on a conversation.

If the physician suspects aphasia, the patient is usually 

referred to a speech-language pathologist, who performs 

a comprehensive examination of the person’s 

communication abilities. The person’s ability to speak, 

express ideas, converse socially, understand language, and 

read and write are all assessed in detail.

How is aphasia treated? 

Following a brain injury, tremendous changes occur in the 

brain, which help it to recover. As a result, people with 

aphasia often see dramatic improvements in their 

language and communication abilities in the first few 

months, even without treatment. But in many cases, 

some aphasia remains following this initial recovery 

period. In these instances, speech-language therapy is 

used to help patients regain their ability to communicate.

Research has shown that language and communication 

abilities can continue to improve for many years and 

are sometimes accompanied by new activity in brain 

tissue near the damaged area. Some of the factors that 

may influence the amount of improvement include the 

cause of the brain injury, the area of the brain that was 

damaged and its extent, and the age and health of 

the individual.

Aphasia therapy aims to improve a person’s ability to 

communicate by helping him or her to use remaining 

language abilities, restore language abilities as much as 

possible, and learn other ways of communicating, such as 

gestures, pictures, or use of electronic devices. Individual 

therapy focuses on the specific needs of the person, while 

group therapy offers the opportunity to use new 

communication skills in a small-group setting.

Recent technologies have provided new tools for 

people with aphasia. “Virtual” speech pathologists 

provide patients with the flexibility and convenience 

of getting therapy in their homes through a computer. 

The use of speech-generating applications on mobile 
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devices like tablets can also provide an alternative 

way to communicate for people who have difficulty

using spoken language.

Increasingly, patients with aphasia participate in activities, 

such as book clubs, technology groups, and art and 

drama clubs. Such experiences help patients regain 

their confidence and social self-esteem, in addition

to improving their communication skills. Stroke clubs, 

regional support groups formed by people who have had 

a stroke, are available in most major cities. These clubs 

can help a person and his or her family adjust to the life 

changes that accompany stroke and aphasia. 

Family involvement is often a crucial component of 

aphasia treatment because it enables family members to 

learn the best way to communicate with their loved one. 

Family members are encouraged to: 

} Participate in therapy sessions, if possible.

} Simplify language by using short, uncomplicated 

sentences. 

} Repeat the content words or write down key words to 

clarify meaning as needed. 

} Maintain a natural conversational manner appropriate 

for an adult. 

} Minimize distractions, such as a loud radio or TV, 

whenever possible. 

} Include the person with aphasia in conversations. 

} Ask for and value the opinion of the person with 

aphasia, especially regarding family matters. 

} Encourage any type of communication, whether it is 

speech, gesture, pointing, or drawing. 

} Avoid correcting the person’s speech. 

} Allow the person plenty of time to talk. 

} Help the person become involved outside the home.

Seek out support groups, such as stroke clubs. 

What research is being done 

on aphasia? 

Researchers are testing new types of speech-language 

therapy in people with both recent and chronic aphasia 

to see if new methods can better help them recover word 

retrieval, grammar, prosody (tone), and other aspects 

of speech.

Some of these new methods involve improving cognitive 

abilities that support the processing of language, such as 

short-term memory and attention. Others involve activities 

that stimulate the mental representations of sounds, 

words, and sentences, making them easier to access 

and retrieve.

Researchers are also exploring drug therapy as an 

experimental approach to treating aphasia. Some studies 

are testing whether drugs that affect the chemical 

neurotransmitters in the brain can be used in combination 

with speech-language therapy to improve recovery of 

various language functions. 

Other research is focused on using advanced imaging 

methods, such as functional magnetic resonance 

imaging (fMRI), to explore how language is processed 

in the normal and damaged brain and to understand 

recovery processes. This type of research may advance 

our knowledge of how the areas involved in speech and 

understanding language reorganize after a brain injury. 

The results could have implications for the diagnosis and 

treatment of aphasia and other neurological disorders.

A relatively new area of interest in aphasia research is 

noninvasive brain stimulation in combination with speechlanguage therapy. Two such brain stimulation techniques, 

transcranial magnetic stimulation (TMS) and transcranial 

direct current stimulation (tDCS), temporarily alter normal 

brain activity in the region being stimulated. 

Researchers originally used these techniques to help them 

understand the parts of the brain that played a role in 

language and recovery after a stroke. Recently, scientists 

are studying if this temporary alteration of brain activity 

might help people re-learn language use. Several clinical 

trials funded by the National Institute on Deafness and 

Other Communication Disorders (NIDCD) are currently 

testing these technologies.

NIDCD-funded clinical trials are also testing other 

treatments for aphasia. A list of active NIDCD-funded 

aphasia trials can be found at https://ClinicalTrials.gov.
Where can I find additional

information about aphasia?

The NIDCD maintains a directory of organizations that 

provide information on the normal and disordered 

processes of hearing, balance, taste, smell, voice, 

speech, and language. Visit the NIDCD website at 

http://www.nidcd.nih.gov to search the directory. 

Use the following keywords to help you find 

organizations that can answer questions and provide 

information on aphasia: 

} Aphasia

} Speech-language development

} Augmentative and alternative communication

More NIDCD fact sheets on Voice, Speech, 

and Language:

} Apraxia of Speech 

Visit the NIDCD website at http://www.nidcd.nih.gov

to read, print, or download fact sheets.

For more information, additional addresses and phone 

numbers, or a printed list of organizations, contact us at:

NIDCD Information Clearinghouse

1 Communication Avenue 

Bethesda, MD 20892-3456 

Toll-free Voice: (800) 241-1044 

Toll-free TTY: (800) 241-1055 

Fax: (301) 770-8977 

Email: nidcdinfo@nidcd.nih.gov

http://www.nidcd.nih.gov

Follow the NIDCD on Twitter at @NIDCD

The NIDCD supports and conducts research and 

research training on the normal and disordered 

processes of hearing, balance, taste, smell, voice, 

speech, and language and provides health information, 

based upon scientific discovery, to the public.

Aphasia 

NIH Pub. No. 97-4257

December 2015

NIH...Turning Discovery Into Health®