Primary Progressive Aphasia

What is primary progressive aphasia?

Primary progressive aphasia (PPA) is a language disorder that is considered one of the clinical subtypes of frontotemporal dementia. Much of the information related to frontotemporal dementia has some relevance to people who have primary progressive aphasia.

Primary progressive aphasia is a neurodegenerative disease in which the early symptoms are characterized by gradually progressive language disturbances. On average, symptoms of primary progressive aphasia begin in the 50s or 60s. As with some patients with frontotemporal dementia, symptoms have been seen in patients as young as 20 and in others over 80.

What are the symptoms of primary progressive aphasia?

The language disturbance associated with primary progressive aphasia is typically grouped into three clinical subtypes.

Progressive nonfluent aphasia
In patients with progressive nonfluent aphasia (PNFA), the ability to produce speech deteriorates. Speech is usually characterized as being “hesitant” and agrammatical.” People often initially become more hesitant to speak, gradually begin to talk less, and eventually become mute.

Research into the language symptoms that characterized progressive nonfluent aphasia suggests a gradually progressive deterioration in knowledge of the grammatical organization and the production of sounds that characterize language. Receptive language (understanding what others say) is usually maintained early in the disease, although increased difficulties with comprehension do occur as the disease progresses.

Semantic dementia
The hallmark of semantic dementia is the loss of word meaning. People with semantic dementia have difficulty generating or recognizing familiar words. For example, when a patient is shown a picture of a boat, a person would be unable to generate the word “boat” and further would not recognize the word “boat” when it was provided. Patients will often make statements such as, “What is boat?” This happens for uncommon words first, but as the disease progresses, higher-frequency nouns become affected. Verbs and abstract words are often spared. Patients will have difficulty reading aloud words that are not spelled phonetically, as pronunciation requires knowledge of the word’s meaning. An example might be the word “yacht.”

Semantic dementia is a “fluent aphasia,” meaning that the grammatical structure and flow of spontaneous speech is retained early in the course of the disease. Patients may be able to use circumlocutions (“talk around”) to convey the meaning of a specific word they fail to generate. In later stages, word-finding pauses in speech emerge, and symptoms progress to difficulty naming familiar objects.

Some people with semantic dementia have problems recognizing familiar objects or faces. This typically occurs when the non-dominant temporal lobe is involved in the pathological process, and the presence of these symptoms can help corroborate the diagnosis.

Logopenic aphasia
Logopenic aphasia is also a “fluent aphasia. In patients with logopenic aphasia, the most prominent deficits are an early defect in finding words. The structure of speech remains grammatically correct, but verbal communication is typically described as having excessively long word-finding pauses. Unlike semantic dementia, the meaning of words is not lost. Confrontation naming (naming an object or illustration) is impaired, but when provided the correct response, a person with logopenic aphasia will recognize the correct word (unlike a person with semantic dementia), and pronunciation is generally intact. Comprehension of single words and simple phrases generally will remain intact, while comprehension of longer or more complex sentences may be impaired.

Social and behavioral symptoms, which are hallmarks of early frontotemporal dementia, do not typically appear early in the clinical course of primary progressive aphasia. However, these symptoms do occur in most patients as the disease progresses.

What causes primary progressive aphasia?

Primary progressive aphasia is a neurodegenerative disease that affects the brain. In most people with progressive nonfluent aphasia, the pathological changes in the brain are related to the protein tau. In those diagnosed with logopenic aphasia, pathological changes of Alzheimer’s disease have been reported in up to 60-80 percent of patients. In those with semantic dementia, pathological changes are more typically associated with the protein TDP-43.

These associations improve our understanding of primary progressive aphasia and frontotemporal dementias. As research progresses, we hope that treatments will become available for the different pathological changes associated with primary progressive aphasia, and that these treatments may then be tailored to an individual’s suspected pathological process.

Heredity/Genetics of primary progressive aphasia

The majority of cases of primary progressive aphasia are sporadic, meaning that the disease is neither inherited nor caused by a genetic mutation. As with other frontotemporal dementias, approximately 10 percent of cases are associated with a known genetic mutation, either in the gene encoding the microtubule associated protein tau (MAPT) or in the gene encoding progranulin (PGRN).

About 20 percent of individuals affected by progressive aphasia have a family history of neurodegenerative disease, such as ALS (Lou Gehrig’s disease), Alzheimer’s disease or Parkinson’s disease. These individuals may have some increased hereditary predisposition for developing a neurodegenerative disease.

What are risk factors for primary progressive aphasia?

Having a family history of frontotemporal dementia is associated with an increased risk of developing primary progressive aphasia. There are no other known risk factors for primary progressive aphasia.

How is primary progressive aphasia diagnosed?

Taking a careful history and performing a thorough neurological and cognitive examination is essential to making a diagnosis of primary progressive aphasia. Laboratory and other diagnostic tests may be performed to exclude other possible contributors to a person’s symptoms. For some patients, neuropsychological testing may help to confirm the diagnosis once it is suspected and can help to emphasize to families the language-specific nature of a person’s symptoms.

An MRI scan of the brain’s structure may identify atrophy (shrinking) in parts of the brain characteristic of primary progressive aphasia. In progressive nonfluent aphasia, this characteristically involves the inferior frontal gyrus, dorsolateral prefrontal cortex and other parts of the frontal lobes. In semantic dementia, atrophy is more prominent in the anterior temporal regions. In logopenic aphasia, atrophy typically appears in the temporal-parietal junction and the temporal-occipital junction. Functional brain imaging with FDG-PET or SPECT may also provide corroborative evidence to support the diagnosis and classification of primary progressive aphasia.

Laboratory investigations, cerebrospinal fluid analysis, EEG or other testing may be recommended to exclude other medical or neurologic conditions. These tests may or may not be recommended, depending upon an individual’s clinical presentation. If ALS (Lou Gehrig’s disease) is suspected, electromyography (EMG) may be recommended to confirm this diagnosis.

What treatments exist for primary progressive aphasia?

There is no cure for primary progressive aphasia. Treatment focuses on medications that may alleviate the severity of symptoms associated with the disease and help to ensure the safety of patients and those around them.

Speech therapy can help an individual maintain language function. It can also help family members and caregivers understand the person’s symptoms and develop alternative communication strategies. Many patients with primary progressive aphasia retain areas of preserved intellectual function even after language deficits have progressed, resulting in significant frustration.

Additional information related to clinical manifestations of primary progressive aphasia, information for caregivers, recent research findings, patient advocacy and links to other Internet-based resources may be obtained through the Association for Frontotemporal Degeneration at:

Association for Frontotemporal Degeneration
Email: info@ftd-picks.org
Website: http://www.ftd-picks.org/
Telephone: (866) 507-7222

A support group exists for patients and caregivers of patients with PPA. They can be contacted through:
Email: PPA-support-subscribe@yahoo.com

Additional information regarding aphasia and information regarding support for patients and caregivers is available through the National Aphasia Association. They can be contacted at:

National Aphasia Association
Email: naa@aphasia.org
Website: http://www.aphasia.org
Telephone: (800) 922-4622