Neurological Conditions
Aphasia and Neurological Communication Disorders
What aphasia is, its relationship to stroke and other neurological events, and the absence of county prevalence data.
Beginner explanation
Aphasia is a disorder caused by damage to the areas of the brain responsible for language — usually on the left side of the brain. It affects how people express and understand language, and can affect reading and writing too.[1]
Stroke is the leading cause of aphasia. Aphasia can also follow a head injury or brain surgery, develop gradually from a brain tumor, result from brain infections, or arise as part of dementia.[1]
Key definitions
- Fluent aphasia
- Speech flows in long sentences but may carry little meaning; Wernicke’s aphasia is the best-known type and often includes difficulty understanding language.
- Nonfluent aphasia
- Short, effortful phrases that leave out small words; Broca’s aphasia is the best-known type.
- Global aphasia
- Severe difficulty producing and understanding language after extensive damage to language areas.
- Primary progressive aphasia (PPA)
- Aphasia that is the first and most noticeable sign of dementia and worsens over time.
- Dysarthria and apraxia of speech
- Speech disorders that can occur alongside aphasia.
Sources[1]
Condition characteristics
Most people with aphasia are middle-aged or older, but anyone can develop it, including young children. NIDCD cites the National Aphasia Association’s estimate that about 2 million people in the United States live with aphasia, and that about one third of stroke survivors have aphasia.[1]
People with Wernicke’s aphasia are often unaware of their mistakes, while people with Broca’s aphasia usually are aware and can become frustrated. Because the frontal lobe also controls movement, Broca’s aphasia may come with right-sided weakness.[1]
After a transient ischemic attack (“mini-stroke”), language may be affected for hours or days but usually recovers.[1]
Risk factors
Because stroke is the leading cause, the risk factors for stroke — including high blood pressure, heart disease, diabetes and smoking — indirectly raise the risk of aphasia. Other causes include traumatic brain injury, brain tumors, infections and progressive conditions such as Alzheimer’s disease and frontotemporal dementia.[1, 2]
Prevention and public health context
Because stroke is the leading cause, preventing stroke also prevents aphasia caused by stroke. When aphasia does occur, the doctor treating the brain injury often identifies it first and should refer the person to a speech-language pathologist for a full assessment.[1, 2]
Many people improve a great deal in the first few months after a stroke or brain injury, and language can keep improving for years. Speech-language therapy helps people use remaining abilities, restore language where possible and learn other ways to communicate, such as gestures, pictures or electronic devices. Access to therapy is one of the factors that affects recovery.[1]
Texas data context
No county-level aphasia measure exists, so none is mapped. The related PLACES stroke measure shows the modeled share of adults who report ever having had a stroke — the leading cause of aphasia — but it does not tell us how many of those adults have aphasia.[1, 3]
Related measures on the Explore map
- Stroke among adults (modeled estimate)
Advanced material (optional)
Primary progressive aphasia can be caused by different types of dementia, including Alzheimer’s disease, vascular dementia, Lewy body dementia and frontotemporal dementia. Researchers are still learning how particular PPA subtypes relate to particular dementias.[1]
Technology such as remote therapy with speech-language pathologists and speech-generating apps is expanding access to treatment, and group activities like book clubs and choirs can help people rebuild confidence and communication skills.[1]
References
- Aphasia. National Institute on Deafness and Other Communication Disorders (NIH). https://www.nidcd.nih.gov/health/aphasia (accessed 2026-10-18).
- Risk Factors for Stroke. Centers for Disease Control and Prevention. https://www.cdc.gov/stroke/risk-factors/index.html (accessed 2026-10-18).
- PLACES Measure Definitions: Health Outcomes. Centers for Disease Control and Prevention. https://www.cdc.gov/places/measure-definitions/health-outcomes.html (accessed 2026-10-18).