What Causes Aphasia? Common Triggers Explained Simply
Imagine knowing exactly what you want to say but not being able to get the words out. Or hearing someone speak, but the words feel scrambled and unfamiliar. That’s the reality for people with aphasia—a communication disorder that affects how the brain processes language. It can impact speaking, understanding, reading, or writing.
But what causes aphasia? Why does it happen, and who is at risk? In this post, we’ll break it down simply—no medical degree required.
What Is Aphasia?
Aphasia is a language disorder caused by damage to parts of the brain responsible for communication—usually the left hemisphere, where most language functions are located.
It’s not a problem with intelligence. People with aphasia still know what they want to say. The challenge is in accessing or expressing language because the pathways in the brain are disrupted.
Key Fact:
Aphasia is always caused by brain damage—not by mental decline or emotional stress.
Common Causes of Aphasia
Let’s walk through the most common triggers of aphasia, explained in plain language.
1. Stroke
This is the most common cause of aphasia.
A stroke happens when blood flow to part of the brain is cut off, either because of a blockage (ischemic stroke) or a burst blood vessel (hemorrhagic stroke). When brain cells don’t get the oxygen and nutrients they need, they die—and if the area damaged controls language, aphasia can result.
Why Stroke Causes Aphasia:
● The brain’s language centers (like Broca’s area and Wernicke’s area) are especially vulnerable during a stroke.
● Damage may be sudden and severe, depending on how long the brain goes without oxygen.
Symptoms After Stroke:
● Trouble speaking clearly
● Mixing up words or using the wrong ones
● Difficulty understanding others
● Challenges with reading and writing
Not everyone who has a stroke develops aphasia, but it’s a frequent outcome when the left side of the brain is affected.
2. Traumatic Brain Injury (TBI)
A fall, car accident, or head injury can lead to a traumatic brain injury, or TBI. If the left side of the brain or specific language-processing areas are damaged, aphasia can develop.
Why TBI Triggers Aphasia:
● Physical impact can bruise or tear parts of the brain.
● Swelling and bleeding (even if temporary) can interrupt communication signals in the brain.
● The injury may affect multiple brain functions, including memory and problem-solving, along with language.
Who's at Risk:
● Athletes in contact sports
● Older adults prone to falls
● Anyone involved in serious accidents
Recovery from TBI-related aphasia varies. Some people see significant improvement with therapy, while others may have lasting symptoms.
3. Brain Tumors
A brain tumor, whether benign (non-cancerous) or malignant (cancerous), can press on or invade the brain’s language centers. This pressure can disrupt the ability to process or produce language.
How Tumors Cause Aphasia:
● Tumors growing in or near language areas interfere with neural activity.
● Surgical removal, chemotherapy, or radiation may also impact surrounding brain tissue and lead to temporary or permanent language changes.
Red Flags:
● Gradual decline in speaking or understanding
● Personality changes
● Seizures or headaches
Aphasia caused by tumors tends to develop gradually, unlike the sudden onset seen with strokes or injuries.
4. Brain Infections
Serious infections that affect the brain—like encephalitis (brain inflammation) or meningitis (inflammation of the brain’s protective layers)—can cause aphasia.
Why:
● Infections can lead to swelling or tissue damage in areas that handle speech and comprehension.
● The immune response itself may damage healthy brain cells.
While less common than strokes or trauma, infection-related aphasia may improve with treatment of the infection and speech-language therapy.
5. Neurodegenerative Diseases
Certain progressive conditions gradually damage the brain and can lead to a specific form of aphasia called Primary Progressive Aphasia (PPA).
Unlike other types of aphasia that occur suddenly, PPA starts slowly and worsens over time.
Conditions Linked to PPA:
● Frontotemporal dementia
● Alzheimer’s disease
● ALS (Amyotrophic lateral sclerosis)
Early Signs of PPA:
● Trouble finding the right word
● Pausing frequently in conversation
● Grammar errors or jumbled speech
There’s no cure for PPA, but therapy can help individuals maintain communication skills as long as possible.
6. Seizures and Epilepsy
Seizures that affect the left side of the brain can sometimes lead to transient aphasia—a temporary inability to speak or understand language.
This type of aphasia may:
● Last from a few minutes to hours
● Occur after a seizure (called postictal aphasia)
● Be a warning sign of an underlying neurological condition
If you or someone you know experiences this, it’s important to seek medical evaluation.
Types of Aphasia (Brief Overview)
Not all aphasia is the same. The cause often determines the type and severity.
Here are a few common types:
| Type | Main Symptoms | Common Cause |
|---|---|---|
| Broca’s Aphasia | Slow, broken speech; good comprehension | Stroke (frontal lobe) |
| Wernicke’s Aphasia | Fluent but meaningless speech; poor comprehension | Stroke (temporal lobe) |
| Global Aphasia | Severe impairment in all language areas | Major stroke or trauma |
| Anomic Aphasia | Trouble finding words, especially nouns | Various causes |
| Primary Progressive Aphasia | Gradual loss of language ability | Neurodegenerative disease |
| Type | Main Symptoms | Common Cause |
|---|---|---|
| Primary Progressive Aphasia | Gradual loss of language ability | Neurodegenerative disease |
Can Aphasia Be Treated?
Yes. Treatment depends on the cause, severity, and timing. Some people recover fully; others learn new ways to communicate.
Common Treatments:
● Speech-language therapy (core approach)
● Group therapy for practicing conversation
● Assistive devices (apps, communication boards)
● Family involvement to support communication at home
For stroke or injury-related aphasia, early intervention improves outcomes. For progressive types, therapy focuses on preserving abilities and adapting communication methods.
Final Thoughts
Aphasia doesn’t discriminate. It can affect anyone after a stroke, injury, tumor, or illness. The most important step is understanding the cause—and getting the right support.
If you or a loved one is showing signs of aphasia, consult a medical professional and a speech-language pathologist. The earlier you intervene, the better the chance for recovery or improvement.
Need Help with Aphasia?
At Anywhere Speech & Language, we offer personalized online therapy for individuals with aphasia, no matter where you are. Whether you’re recovering from a stroke, living with PPA, or supporting a loved one through brain injury—we're here to help you find your voice again.
Contact us today to get started.