Mixed transcortical aphasia is a more severe form of aphasia that causes an inability to speak or understand others. It is similar to global aphasia in that it affects multiple aspects of a person’s language skills. However, with mixed transcortical aphasia, the person can still repeat words they hear or sing familiar songs.
In this article, you will learn more about the causes and characteristics of mixed transcortical aphasia, and what you can do to treat it.
Causes of Mixed Transcortical Aphasia
Mixed transcortical aphasia is a unique form of language disorder. Unlike other types of aphasia, the main language areas of the brain (Broca’s and Wernicke’s areas) are not damaged. Rather, the language association areas are injured. These areas surround Broca’s and Wernicke’s areas and connect them to the rest of the brain.
Doctors believe that damage to the language association areas actually isolates Broca’s and Wernicke’s areas from the rest of the brain. This prevents the production of spontaneous speech and comprehension of written and spoken language. That is why another term for mixed transcortical aphasia is isolation aphasia.
The most common cause of mixed transcortical aphasia is a watershed stroke, which is a stroke that affects one or more of the watershed regions of the brain. These regions are located at the farthest point from the major cerebral arteries in the brain. Because they are so far from the arterial supply, they are especially vulnerable to a decrease in blood flow.
The carotid artery is one of the main arteries that supply blood to the language association areas of the brain. Therefore, when a stroke occurs in this artery, it can severely damage these areas and lead to aphasia.
Symptoms of Mixed Transcortical Aphasia
Mixed transcortical aphasia shares many of the same characteristics as global aphasia, such as the inability to speak or comprehend language. It also possesses some unique characteristics of its own.
For example, a defining feature of mixed transcortical aphasia is a striking ability to repeat words, phrases, and even entire sentences. This makes it the functional opposite of conduction aphasia, in which the person cannot repeat any words at all.
The following are a few of the most common symptoms of mixed transcortical aphasia:
- Slow, halting speech
- Speech does not have typical rhythm or prosody
- Spoken language is mostly a repetition of what was said to them (echolalia)
- Difficulty initiating speech
- Impaired reading and writing abilities
- Repetition skills are completely intact or only mildly impaired. For example, they could repeat a 3-4 word sentence correctly.
Because mixed aphasia is so similar to global aphasia, treatment will also take a similar approach.
Treatment for Mixed Transcortical Aphasia
The best way to treat mixed transcortical aphasia, as with most types of aphasia, is through speech therapy. Speech therapy exercises work by activating neuroplasticity.
Neuroplasticity refers to the brain’s ability to form neural pathways in response to repetition or changes in environment. These pathways can allow undamaged portions of the brain to take control of functions that were previously controlled by damaged ones.
Therefore, even if a stroke severely damages the brain regions that normally control language association, it is still possible for other areas to compensate.
To activate neuroplasticity, the patient must engage in repetitious exercise. The more you stimulate your brain through exercise, the more neural pathways your brain will create in response. With these new neural pathways in place, you can begin to regain speech function.
One effective speech therapy exercise for treating mixed transcortical aphasia is constraint-induced language therapy, which we will discuss below:
Constraint-Induced Language Therapy
Constraint-Induced Language Therapy (CILT) was designed to help people with severe aphasia regain their speaking skills.
The goal of CILT is to force the person to engage their speaking by eliminating compensatory tactics. As they practice this skill, the brain can relearn how to use and understand language and the patient can hopefully begin to regain speech function again.
During constraint-induced language training, a patient must:
- Avoid using tactics such as gestures or writing
- Communicate only by speaking
- Practice heavily for at least one hour per day.
With enough practice, you can activate neuroplasticity and should see improvements in your speech.
However, one difficulty during therapy for mixed transcortical aphasia is that the patient has not only lost speaking skills but language comprehension as well. Therefore, the patient may not be able to understand the instructions the speech therapist gives them, which will make participating in CILT difficult, if not impossible.
If CILT is too difficult, another effective treatment is drawing therapy. Drawing has been shown to activate regions in the right hemisphere, which can allow patients to access knowledge in a different side of their brain.
Studies conducted on drawing therapy show that it increased naming abilities in patients with both acute and chronic aphasia. It was especially useful in patients with global aphasia. Since mixed transcortical aphasia shares so many characteristics with global aphasia, it’s likely that drawing therapy will also be effective for those patients.
It’s important to note that the act of drawing itself is what is critical for engaging the brain, not the quality of the drawing. Therefore, even people without any artistic background can benefit from drawing therapy.
How Long Does Recovery from Mixed Aphasia Last?
According to most statistics, 60% of stroke patients still have speech problems six months after their stroke. Because mixed transcortical aphasia is a severe form of aphasia though, the recovery may take even longer.
However, while aphasia recovery can take years, improvement is always possible. In fact, even decades after a stroke, neuroplastic changes in the brain can still occur.
The brain requires constant stimulation to trigger neuroplasticity. That’s why daily practice of speech therapy exercises is so crucial. Just ten minutes a day can lead to many benefits later on. The more you stimulate the brain, the more progress you can make in your aphasia recovery.
Understanding Mixed Transcortical Aphasia
Mixed transcortical aphasia is a severe type of aphasia that impairs a person’s speech and comprehension skills. But the patient’s repetition skills remain intact. Therefore, they will mostly repeat what they hear others say, a condition known as echolalia.
Because transcortical aphasia shares so many similarities with global aphasia, treatment can also take a similar approach. If constraint-induced language therapy is too difficult at first, patients may benefit from simpler treatments, such as drawing therapy.
As with all types of aphasia, the best way to recover is to work closely with a speech therapist, who can assess your symptoms and devise a treatment plan that meets your specific needs.
Featured Image: ©iStock/Pornpak Khunatorn