Primary Progressive Aphasia (PPA)

Primary progressive aphasia (PPA) is a condition in which language gradually breaks down, while memory and other thinking skills are at first relatively unaffected. "Aphasia" means a loss of language. In PPA it is caused by slowly progressive damage to the language areas of the brain, usually in the temporal and frontal lobes, rather than by a stroke or injury.

Most PPA is a form of frontotemporal dementia (FTD), sometimes called "language-led" dementia. Symptoms usually begin before the age of 65. The actor Bruce Willis brought PPA into public view after his family announced in 2022 that he had aphasia, and later that he had FTD (read his story).

The types of PPA

There are three main types, each with a different pattern of language problems.

Semantic variant PPA (semantic dementia)

People gradually lose the meaning of words. Speech stays fluent and grammatically correct, but they:

• Struggle to name objects, people and places, starting with less common words
• Use vague words such as "thing" or "thingy" instead of specific names
• Lose understanding of what words mean, so they may ask "what is a…?" about everyday words
• Later lose knowledge of what objects are for, such as how to use cutlery or a toothbrush

Changes in behaviour similar to behavioural variant FTD are common, such as rigid routines or changes in eating.

Non-fluent variant PPA (also called agrammatic or progressive non-fluent aphasia)

People have increasing difficulty producing speech. They may:

• Speak slowly and with great effort, with many pauses
• Leave out small linking words, so speech sounds like a telegram ("Tired. Going bed now.")
• Make grammar mistakes and put words in the wrong order
• Struggle to form the sounds of words (apraxia of speech)
• Understand single words but find complex sentences harder

Over time, most people with non-fluent variant PPA stop speaking. Some also develop movement problems similar to Parkinson's disease, such as stiffness, slowness and poor balance.

Logopenic variant PPA

People have trouble finding words and pause often during conversation, but understand words and use grammar correctly. They may struggle to repeat sentences. Unlike the other two types, logopenic PPA is usually caused by the brain changes of Alzheimer's disease rather than FTD. That matters for treatment and planning, so an accurate diagnosis is important.

Some people do not fit neatly into one type and are described as having mixed or atypical PPA.

How PPA is diagnosed

The hallmark of PPA is communication problems that get worse over two to three years without major changes in other thinking or behaviour. Diagnosis usually involves a neurologist and a speech and language therapist, and may include:

• Detailed language testing: naming, understanding, repeating, reading and writing
• An MRI scan, which can show shrinkage in specific language areas
• A PET scan, which can show changes in how the brain uses energy in language areas, or check for proteins linked to Alzheimer's disease
• Blood tests or a lumbar puncture to rule out other conditions
• Genetic testing in some cases, especially with a family history (see is frontotemporal dementia hereditary?)

How PPA progresses

PPA gets worse over time, but often slowly. Many people continue to look after themselves and take part in daily activities for several years. Eventually people with PPA lose the ability to speak and write, and later to understand spoken or written language; this may take anywhere from 3 to 15 years. As the condition spreads, changes in behaviour, memory and movement often develop, and the different types of FTD start to look more alike.

Survival varies by type. Semantic dementia tends to progress the most slowly, with a median survival of around 12 years from the first symptoms. See the stages of frontotemporal dementia for more on life expectancy.

Treatment and support

There is no treatment that slows or stops PPA, but a lot can be done to help people communicate and stay involved:

• Speech and language therapy can teach strategies for communicating as speech declines, such as gestures, writing, pictures, communication books and electronic devices. Starting early, while skills are still good, helps people learn and practise these tools.
• Simplifying conversation: speaking slowly, using short sentences, asking yes/no questions and giving extra time all help.
• Planning ahead: because language will decline, it is important to make decisions about finances, legal matters and future care while the person can still express their wishes.
• Support for families: losing the ability to talk with someone is a profound loss. Support groups for FTD and younger-onset dementia can help families cope.

Related pages

• 7 stages of frontotemporal dementia
• Behavioural variant FTD
• Frontotemporal dementia vs Alzheimer's