Brain Featured

Understanding the impacts of aphasia on the brain

Written by Lindsay Smith

Bruce Willis’ family recently announced that the actor will be retiring because of an aphasia diagnosis. Some may be wondering what aphasia is and how it can impact language and communication abilities. Dr. Sara Mitchell, neurologist at Sunnybrook, explains more about aphasia and how it affects the brain.

What is aphasia

“Aphasia is a disorder of language and communication,” says Dr. Mitchell. “It can impact people’s expression of language, their comprehension of language and it can also impact reading and writing.”

There are two main types of aphasia: expressive aphasia and receptive (comprehension) aphasia.

Expressive aphasia tends to affect Broca’s area of the brain in the frontal lobe, the area that controls expression and speech.

“With [expressive aphasia], someone might have difficulty with producing speech, such as finding the right words,” Dr. Mitchell says. “For instance, if they can’t find the word they’re looking for, they may replace it with a word that has a similar meaning. They might say ‘sofa’ instead of ‘table,’ or they might replace it with another word that sounds like table. Generally, people with expressive aphasia have intact comprehension of speech.”

Individuals with an expressive aphasia also tend to have slower speech; it takes them longer to say what they want to because they’re either having trouble finding the right words, putting them together or articulating them.

Comprehension aphasia tends to affect Wernicke’s area of the brain in the temporal lobe, the area that controls language comprehension.

“People have difficulty with understanding speech, and often their speech is fluent but sounds like a ‘word salad,’ so they’re able to produce speech, but it’s much less comprehensible,” says Dr. Mitchell.

It is also possible for someone to have mixed symptoms of both expressive and comprehension aphasia.

What causes aphasia

There are several potential causes of aphasia. Many people with aphasia have suffered a stroke that has impacted an area of their brain controlling language, or a critical component of the language network.

“But there are other types of insults to the brain that can result in aphasia,” says Dr. Mitchell, including a tumour or other structural lesion, or a “neuro-degenerative process” such as a dementia that predominantly affects language called a ‘primary progressive aphasia.

And while aphasia may sound the same as dementia, Dr. Mitchell says there is a distinction.

“Dementia is an umbrella term that refers to memory and thinking difficulties that impact the person’s day-to-day functioning. There are many different types of dementia,” she says.

The most common type of dementia is Alzheimer’s disease, which primarily impacts memory, but can also affect language. But Dr. Mitchell says that in Alzheimer’s disease, a person’s memory is classically most affected, with language and other thinking problems being secondary or later problems.

“We classify different types based on what the first, main symptom is,” says Dr. Mitchell. “The aphasia type of dementia is called a ‘primary progressive aphasia’ and is a rarer type of dementia where the primary problem from early on in the disease course if language disturbance and this can remain the primary problem for the majority of the disease course.”

Treatment options

Dr. Mitchell says the most important treatment for aphasia is communication and language therapy.

Typically, speech language pathologists work with aphasia patients, providing intensive communication training, adaptive techniques and assistive technology devices to help people function.

“The brain does have the ability to maintain connections that are already formed, so working on maintaining language function and functional communication is really important,” says Dr. Mitchell. “It’s such an important part of human connection and interaction, to be able to express yourself and understand those around you.”

About the author

Lindsay Smith