Primary Progressive Aphasia
What is primary progressive aphasia (PPA)?
Primary progressive aphasia (PPA) is caused by degeneration in the parts of the brain that control speech and language (the left, or ‘dominant,’ side of the brain in the frontal, temporal and parietal regions). This type of aphasia begins gradually, with speech or language symptoms that will vary depending on the brain areas affected by the disease. For example, in one type of PPA, people may initially have trouble producing speech, or articulating, whereas in another variant, word-finding and comprehension problems are more pronounced. PPA has three variants: nonfluent/agrammatic, logopenic and semantic. These syndromes result from a variety of underlying diseases, but frontotemporal lobar degeneration (FTLD) (both tau and TDP-43 subtypes) or Alzheimer’s disease are most often the cause.
The majority of patients with PPA have problems expressing themselves with language while memory stays relatively intact, especially during the first two years of decline. Difficulties reading and writing may develop as the disease progresses. At the UCSF Memory and Aging Center, we have found a small group of patients with PPA who develop new creative skills in music and art as their language skills decline.
Semantic Variant PPA
(also known as semantic dementia or PPA-Semantic)
The most common complaint of people with semantic variant PPA is increasing trouble naming people, objects, facts and words. Remembering names of people, even good friends, can become quite difficult for people with this type of PPA. As the disease progresses, patients lose not only the ability to name things, but also the meaning, or conceptual knowledge, for the words that they are trying to name. For example, early in the illness, a patient might lose the word for a low-frequency word such as falcon, later on forget the word for a more common word like chicken, then call all winged creatures "bird," and eventually call all animals "things". "What is a bird?" might be a typical response for someone in the advanced stages of the disease. People with semantic variant PPA usually know they are having trouble finding words. They may have increasing trouble understanding conversation, as their understanding of words declines. Speech production skills and memory for day-to-day events are usually spared. Like the behavioral variant of FTD, muscle function, an understanding of where one is, and the sense of day and time tend to function as before. Some people may develop an inability to recognize familiar faces. In the late stages, similar behavioral changes to those seen in behavioral variant frontotemporal dementia (bvFTD) may appear. Symptoms associated with the semantic variant are caused by damage to the left temporal lobe, an area critical for assigning meanings to words. Semantic variant PPA accounts for 20% of frontotemporal dementia (FTD) cases.
Nonfluent/Agrammatic Variant PPA
(also known as progressive nonfluent aphasia or PPA-Agrammatic)
People with nonfluent PPA tend to come to the doctor's office with complaints about “speech difficulty,” or pronouncing words. Unlike cases of semantic variant PPA, in which a person maintains the ability to speak but loses word meanings, patients with the nonfluent variant have difficulty producing language fluently even though they retain the meanings of words. Patients may talk slowly or have difficulty articulating words, particularly when talking on the phone or in groups of people. Understanding long or complex sentences may become difficult as well. Over time, patients with the nonfluent variant may begin to use short sentences, omitting smaller words, like articles and adjectives. In recent years it has become apparent that many patients with the nonfluent variant go on to develop Parkinsonian symptoms that overlap with progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD), such as an inability to move the eyes side-to-side, muscle rigidity in the arms and legs, and weakness in the muscles around the throat. These patients tend not to show the behavioral characteristics of FTD until quite late in the disease, and they are keenly aware of their difficulties. Depression and social withdrawal are common features of the nonfluent variant. As the disease progresses, less and less language is used, as speech production becomes increasingly difficult. Symptoms associated with the nonfluent variant of PPA are caused by changes in the left posterior frontal lobe and surrounding brain areas. The nonfluent PPA variant accounts for about 20% of all people with frontotemporal dementia.
Logopenic Variant PPA
(also known as logopenic progressive aphasia or PPA-Logopenic)
Word-finding difficulties are the most prominent feature in patients with logopenic PPA. While speech production skills are spared, patients with this variant may talk slowly, pausing often to try to think of the words they want to say. Over time, patients with logopenic PPA may have trouble understanding long or complex verbal information, due to problems holding onto lengthy information that they hear. Patients with the logopenic variant do not lose the underlying meanings of words, as is the case in the semantic variant. Language difficulties associated with the logopenic variant are due to shrinking, or atrophy, in the left posterior temporal cortex and inferior parietal lobule. Alzheimer’s disease is the most common cause of logopenic PPA.
Treatment of primary progressive aphasia (PPA)
People with language difficulties may benefit from speech therapy to help them learn alternative ways to supplement and compensate for their lost skills. Maintaining adequate communication and social connections is critical. Unlike many people who develop aphasia from head injury or stroke, people with PPA do not typically improve with time, but a therapist may be helpful in maximizing abilities and exploring other ways to communicate. Non-verbal techniques for communicating, such as gesturing or pointing to pictures may help people express themselves.
Aphasia identification cards explaining that the person has a language problem may be helpful. Many speech pathologists and occupational therapists have their own practices, while others are available through local hospitals and medical centers. Ask your doctor for a referral.
Resources for primary progressive aphasia (PPA)
- 2011 updated diagnostic criteria for PPA
- International PPA Connection
- The National Aphasia Association (NAA)
- The Primary Progressive Aphasia Program at Northwestern University