To break down the term primary progressive aphasia: ‘primary’ relates to it being brain tissue changes rather than an external cause, ‘progressive’ means worse over time and ‘aphasia’ refers to a neurological (brain-related) language problem.

The three most common types of PPA are:

• Progressive nonfluent aphasia (PNFA), also known as the nonfluent/agrammatic variant of PPA (nfvPPA). PNFA can affect a person’s ability to use speech, form sentences that make sense, or use grammar appropriately. For instance, somebody with PNFA might have problems producing the words that they want to say – their speech might sound very slow or physically difficult, or they may get the order of words in a sentence mixed up. Difficulties with word order and sentences can be present in writing as well as speech.
• Semantic dementia (SD), also known as the semantic variant of PPA (svPPA). SD affects a person’s ‘semantic memory’, which is the store of knowledge that we gain throughout our lives about the world we inhabit – who people are, what objects are, and what words mean. If you said to somebody with semantic dementia “Please pass me the scissors”, they might reply, “What are scissors?” – although this might only happen with less common items in the early stages. People with SD can speak quite fluently – but they may seem to use more general words, such as “thingy”.
• Logopenic aphasia (LPA), also known as the logopenic variant of PPA (lvPPA). Somebody with LPA might have difficulties with searching for the right word to say, although their ability to physically produce speech is not affected. These word-finding difficulties can lead to long pauses in conversations. People with LPA can also get parts of words muddled up, for instance saying “aminal” instead of “animal”.

PNFA and SD fall within a larger group of dementias called frontotemporal dementia (FTD), indicating the parts of the brain mainly affected in these conditions: the frontal and temporal lobes.

LPA, by contrast, is usually caused by the same ‘proteins’ in the brain that cause Alzheimer’s disease – some people refer to it as an unusual (‘atypical’) form of Alzheimer’s disease.

PPA usually starts between the ages of 50 and 70. However, it can also affect older people and rarely, younger people as well.

Causes

The average adult human brain contains around 100 billion cells. These cells are maintained and supported by proteins that keep them functioning healthily. In PPA, these healthy proteins start to go wrong within cells in areas of the brain that control language (known as the frontal and temporal lobes). This ultimately causes damage to these brain cells, and this damage spreads outwards. For PNFA and SD, these are usually the same proteins as in a larger group of dementias called frontotemporal dementia (FTD), whilst LPA is usually caused by problems with the same proteins seen in Alzheimer’s disease.

We do not fully understand what might cause these proteins to stop working healthily in people with PPA, and why this seems to happen in the parts of the brain that control language. In rare cases, PPA can be genetic, meaning that a specific faulty gene might be causing these proteins to stop working in the way that they should. This is only the case for a small minority of people with PPA. If you have a genetic form of PPA it may also be referred to as familial frontotemporal dementia (fFTD). For more information about this please visit our fFTD page.

In non-genetic cases of PPA (which account for around 90% of people with PPA), we are not yet sure what causes the disease to happen. Key questions remain as to why these proteins stop working and cause damage in certain areas of the brain, and why (and how) they particularly affect the language system in the brain.

However, it is important not to lose sight of the tremendous advances in understanding PPA that have already been made – advances that have been directly inspired and enabled by patients, their families and supporters.

Diagnosis and testing

To diagnose PPA, a neurologist will usually conduct several assessments to determine whether the person is having difficulties with language more than with anything else – for a diagnosis of PPA, problems with language must be the first and most obvious symptoms. Next, they will need to determine whether the person’s language problems are caused by PPA, or by something else. To do this, they will ask for a detailed history: what difficulties is the person having, and when did they start? Ideally, they will ask the same questions of someone who knows the person well.

A neuropsychologist may also assess how exactly a person’s language is affected. For example, is it their ability to produce speech, problems finding the right word to say, their understanding of words, or a combination of all three?

An MRI brain scan can also be helpful – this allows the neurologist to see a picture of the inside of the person’s brain – and they can look for any areas that show signs of damage. As most people’s language systems are in the left side of their brain, the neurologist might look for changes here, and specifically within the frontal and temporal lobes that are known to be affected in PPA.

Sometimes, the neurologist might ask for a lumbar puncture or “spinal tap”. The fluid that can be taken in this way is the same fluid that flows around in our brains – and so analysing this fluid can give an indication as to whether the person’s PPA might be caused by the same proteins that cause typical Alzheimer’s disease.

PPA is very rare, and many people describe long and frustrating journeys through different medical professionals before receiving a diagnosis. Even then, many people will not be told which subtype of PPA they are likely to have. Others will be told that whilst they clearly have a type of PPA, their symptoms don’t neatly match to one of the three major variants described here.

It is therefore important that healthcare professionals are better informed about PPA and equipped to recognise the symptoms. Rare Dementia Support is working to improve understanding of PPA and other rare dementias and there are some useful resources available on our Learning page.

By increasing awareness and understanding of PPA, we hope to ensure that healthcare professionals and communities are better equipped to support people affected by a diagnosis. Help us by sharing your stories and contacting us at contact@raredementiasupport.org.

< Back to PPA main page