Primary progressive aphasia is a type of dementia, most often due to frontotemporal degeneration but may also be caused by Alzheimer’s disease. Primary progressive aphasia is progressive, as the name implies, and shortens lifespan.
There are three main subtypes of primary progressive aphasia. They include logopenic variant primary progressive aphasia, semantic variant primary progressive aphasia, and nonfluent/agrammatic variant primary progressive aphasia. Sometimes a person’s symptoms do not fit well into any of these three main subtypes, and that is called unclassifiable primary progressive aphasia.
In logopenic variant primary progressive aphasia, a person’s initial symptoms tend to be word finding difficulty. Sentences become full of many pauses, and there may be round-about ways they try to get their point across due to not being able to think of a more precise word (circumlocutions). Mixing up the letters in words may also occur (phonemic paraphasic errors). As the disease progresses, non-language functions become more affected, such as memory. Logopenic variant primary progressive aphasia is also known as the language variant of Alzheimer’s disease, because it most commonly is due to Alzheimer’s disease, and not frontotemporal degeneration like the other subtypes.
Semantic variant primary progressive aphasia is sometimes called semantic dementia. In this type of dementia, a person has problems not just with finding words, but also with understanding the meaning of words. A caregiver may notice a lot of “what is…” questions in conversation. Objects may be used incorrectly because knowledge of what they are is also lost. Other symptoms include problems with reading or writing certain words properly (surface dyslexia or dysgraphia), and difficulty with recognizing familiar faces (prosopagnosia). As the disease progresses comprehension worsens, and behavioral and dietary changes may develop, similar to behavioral variant frontotemporal dementia.
Nonfluent/agrammatic variant primary progressive aphasia is the least common of the main three subtypes of primary progressive aphasia. In this type of dementia, speech is very difficult for a person to produce, resulting in slow, effortful, broken sentences with incorrect grammar. Understanding complex instructions may be difficult, however, the meaning of individual words is retained. As the disease progresses, a person may lose the ability to speak, swallowing problems may develop (dysphagia), and more physical symptoms of parkinsonism can develop as in corticobasal degeneration, especially on the right side of the body.
There is no cure for primary progressive aphasia. A comprehensive evaluation can clarify if a person’s symptoms are due to primary progressive aphasia and which subtype it is. Since each subtype has a different expected course of symptoms, anticipatory guidance with safety recommendations can be maximized by knowing which specific condition a person has. Speech-language therapy and swallow therapy are often recommended as well.