Primary progressive aphasia: types, symptoms, outlook

The name breaks down into three parts. "Primary" means language is the first and most prominent thing to go wrong. "Progressive" means symptoms keep developing. "Aphasia" means a loss or weakening of the ability to use and understand language. Rare Dementia Support sums it up as a neurological language difficulty that gets worse over time.

PPA is a form of dementia, but it does not look like the memory-led dementia most people expect. A person can follow a TV plot, manage a bank account and recognise family while struggling to find the word for a kettle. That mismatch is one reason the condition is often missed or put down to stress or ageing in the early months.

The NHS lists primary progressive aphasia among the other names for frontotemporal dementia, a condition caused by clumps of abnormal protein in the frontal and temporal lobes of the brain. These areas control language, behaviour and the ability to plan and organise.

Doctors divide PPA into variants according to which part of language is hit hardest. The boundaries are not always clean, and Rare Dementia Support notes that some people have symptoms that do not neatly match any one variant.

Everyone loses a word now and then. What marks PPA is a steady, lasting change that others around the person start to notice and that does not recover with rest or a better night's sleep. Rare Dementia Support points out that the earliest stage may be intermittent, difficult for the person to describe, and recognised mainly by people who know them well.

• Speech that has become slow, laboured or distorted even though the person knows exactly what they want to say.

• Trouble understanding longer or more complicated sentences.

• Leaving out small words or using the wrong word forms, for example "I enjoy going swim".

• Reaching for general words such as "thing" in place of the precise word.

• Asking what familiar words mean.

• Long pauses mid-sentence while searching for a word, or swapping letters and syllables inside words.

• Spelling and grammar mistakes in emails or texts that were never a problem before.

In PPA, normally helpful proteins inside brain cells start to go wrong in the language areas of the brain. This damages the cells, and the damage spreads outwards. Rare Dementia Support explains that non-fluent and semantic variants usually involve the same proteins as frontotemporal dementia, whereas the logopenic variant usually involves the proteins seen in Alzheimer's disease.

That difference has practical importance. Because logopenic PPA is often an unusual form of Alzheimer's disease, the charity notes that some medicines used for typical Alzheimer's disease may be worth trying when Alzheimer proteins are the cause. Alzheimer's Society takes a similar view and describes logopenic aphasia as generally a type of Alzheimer's disease rather than frontotemporal dementia.

Why the proteins fail, and why they do so in language regions, is not yet understood. Inherited forms exist but are uncommon. The NHS suggests that anyone with a family history of frontotemporal dementia could ask a doctor about referral to a geneticist.

There is no single test. The NHS says that for frontotemporal dementia, diagnosis draws on an assessment of symptoms, an assessment of mental abilities, blood tests to rule out similar conditions, brain scans and sometimes a lumbar puncture. It is normally helpful to have someone who knows the person well describe the symptoms.

For PPA specifically, Rare Dementia Support explains that a neurologist, or sometimes a psychiatrist, checks whether language is affected more than anything else and whether another cause explains it. A neuropsychologist may analyse exactly which language skills are affected. An MRI brain scan looks for shrinkage in the left frontal and temporal lobes, and a lumbar puncture can help show whether Alzheimer proteins are involved.

The same charity is candid that PPA is relatively rare, that many people describe long journeys through different professionals, and that some are not told which variant they probably have. Asking for a speech and language therapy assessment alongside the neurology review is reasonable.

The NHS states that there is currently no treatment that will slow frontotemporal dementia, but treatments can help control some symptoms. Speech and language therapy is the mainstay for communication. The NHS aphasia page says a therapist can assess symptoms, help improve speaking, reading and writing, and teach different ways to get a message across.

Where aphasia is caused by a condition that worsens over time, the NHS says treatment may focus on learning and practising other ways to communicate, such as drawing, body language or technology. Rare Dementia Support suggests tools such as text messages or video calls in place of phone calls, label-and-picture cues, and thumbs up or down for yes and no when the words get muddled.

• Speech and language therapy for word-finding, speech effort, alternative communication and later swallowing assessment.

• Occupational therapy for technology, home adaptations and keeping everyday tasks manageable.

• Dietitian input through a GP if appetite or eating habits change.

• Planning calls and outings in advance, choosing quieter places when hearing in noise becomes harder.

• Support groups for the person and family, including those run by Rare Dementia Support.

Rare Dementia Support is open about how hard it is to give an accurate forecast for PPA. One person may progress quite quickly while another progresses slowly, and the charity says better prognostic information is one of the biggest gaps in current care. It describes a six-stage framework developed with PPA support groups in the UK and Australia, while stressing that stages are arbitrary and not everyone follows them in order.

Over time, language problems usually widen. Alzheimer's Society says most people with non-fluent variant PPA eventually stop speaking, and that behaviour, movement and swallowing can become affected as the disease spreads. For frontotemporal dementia as a whole, the NHS gives an average survival of around 8 to 10 years after symptoms start, adding that this is highly variable.

Many families find early planning worthwhile. Rare Dementia Support suggests discussing future care wishes, updating a will, considering lasting power of attorney, and telling the DVLA and insurer about the diagnosis if the person drives. It also notes that people with a diagnosis may be entitled to certain welfare benefits and that carers can contact their local Carers' Centre.

See a GP if speech or word-finding has changed over weeks to months and is not getting better. Taking a family member or friend who can describe the changes is helpful, as is writing down examples.

Sudden changes are different. The NHS aphasia page advises calling 999 if someone suddenly has face weakness, arm weakness or numbness, slurred or confused speech, difficulty finding words, or loss of sight in one or both eyes, because these can be signs of a stroke. Sudden aphasia is far more often caused by stroke than by PPA, and stroke needs immediate treatment.