When you’re having a conversation with a friend, multiple parts of your brain are involved. Wernicke’s area, in the temporal lobe, processes the sounds created by speech into something you can understand; it also makes written language comprehensible. Broca’s area, in the front of the left hemisphere, turns your thoughts into words and sends that information to the motor cortex and brain stem, which helps to control your face, mouth, tongue and throat muscles to speak.
When your brain is damaged or begins to deteriorate, your ability to understand or produce language may be affected. Aphasia and dysarthria are common communication disorders that can indicate an issue in the brain. UNC Health neurologist Gwenn Garden, MD, explains the difference between aphasia and dysarthria and what you need to know about these two conditions.
Aphasia vs. Dysarthria
“Aphasia is when the brain has trouble generating and understanding language,” Dr. Garden says.
There are several types of aphasia, depending on the part of the brain that’s affected. Some people may retain comprehension of spoken and written language but be able to speak only in short or incomplete sentences. They may struggle to find the words they want to use.
Others might have difficulty comprehending language. They may speak in long sentences that don’t make sense in the context of the conversation and that include unnecessary or made-up words. They probably aren’t aware that what they say is confusing.
People with global aphasia are unable to generate or understand language.
Dysarthria, on the other hand, is about production of speech, rather than comprehension of language.
“People with dysarthria understand language and complicated commands,” Dr. Garden says. “They can’t control the fine muscle movements related to speech, so if you ask them to say a complex sentence, it may not be comprehensible.”
Dysarthria can cause people to slur or speak at an abnormal volume or pace. Because they haven’t lost the ability to comprehend and process language, people with dysarthria are aware that their speech has changed.
Causes of Aphasia and Dysarthria
Both aphasia and dysarthria can be caused by a stroke.
“If people suddenly develop the symptoms of either aphasia or dysarthria, call 911,” Dr. Garden says. “Treatment in the emergency room can help to preserve or restore the parts of the brain necessary for language.”
It is possible to develop both aphasia and dysarthria at the same time, depending on the type of stroke and the parts of the brain that are affected.
“Neurologists have tests that separate your ability to think and say things from your ability to articulate things,” Dr. Garden says.
Both conditions also can develop slowly over time and may indicate a neurodegenerative disease, such as dementia or Parkinson’s disease. A neurologist will conduct a variety of assessments to determine a diagnosis.
Primary progressive aphasia, which is linked with frontotemporal dementia and Alzheimer’s disease, happens when the brain atrophies and loses the ability to produce and understand written and spoken language.
Less commonly, you can experience aphasia and dysarthria because of brain tumors or infections in your brain.
Also, congenital conditions such as cerebral palsy and autoimmune conditions such as multiple sclerosis can lead to dysarthria.
Treatment and Support for Aphasia and Dysarthria
The treatment for aphasia and dysarthria depends on what is causing the condition. You may see improvements as the underlying causes are treated.
“There isn’t a curative treatment for neurodegenerative diseases, but interventions can be helpful and are worth pursuing,” Dr. Garden says. “Lifestyle changes can also slow the progression of neurodegenerative disease.”
Working with a speech language therapist can help you with aphasia or dysarthria.
For aphasia, you might work on relearning words and practicing communication skills. You may also learn how to use other forms of communication, such as signing or using assistive devices, including computers or communication boards.
For dysarthria, therapy may be more focused on increasing and strengthening muscle movement and practicing adjustments to better control the volume and speed of speech. Dysarthria can progress to affect the muscles involved in swallowing, so you may need to work with a therapist on ways to prevent aspiration, when food or liquid gets in the lungs.
“In the case of a stroke, recovery may happen very slowly, with improvements continuing over the course of a year,” Dr. Garden says. “Some language function may lag in return, and it might be necessary to identify workarounds.”
Frustration and isolation are also common; it’s difficult to not be able to speak or to know that you’re not being understood. Doctors and speech therapists can provide guidance on maximizing communication.
It may also be necessary for you or your loved ones to see a mental health provider to deal with the emotional effects of your symptoms. Dr. Garden says that many diagnoses associated with aphasia and dysarthria are anxiety-provoking, so it’s good to acknowledge those worries.
If you’re concerned about your risk for stroke or neurodegenerative disease, talk to your doctor. Need a doctor? Find one near you.