Primary Progressive Aphasia (PPA) is a disorder caused by degenerative diseases of the brain, in which speech and language functions deteriorate gradually over a period of years, while memory and other abilities remain relatively preserved.

Symptoms can begin as early as the 40's, but can appear any time afterwards. Initially, the symptoms of PPA are confined exclusively to the area of language functions. This can involve things such as increased difficulty thinking of words, problems reading or writing and reduced ability to understand speech. Sufferers may also lose ability to perform even simple mathematical operations and thus are no longer able to handle money. However, as the disease progresses, eventually other abilities such as memory, attention, personality and behaviour, diminish as well.

Patients with PPA can give the impression that they can't remember because they usually can't express themselves well. However, the fact that their memory system is working relatively well is apparent from their actions: they are able to perform activities of daily living independently. They do not get lost. They continue to perform daily chores and routines.

This form of dementia tends to occur more often in men than in women.