Primary progressive aphasia is a rare neurological syndrome that is considered to be a sub-type of frontotemporal dementia. As its name implies, the disease primarily affects a person’s ability to understand and to produce language. In many ways, this person sounds similar to a person who has had some kinds of strokes. It was first described in 1982, by Mesulam, who listed the following diagnostic criteria:
- Gradual decrease in word processing, object naming, and syntax
- Typically intact premorbid language functioning
- Acalculia – difficulty performing simple mathematical calculations
- Ideomotor apraxia – inability to perform pantomimed movements
One thing that distinguishes PPA is that it develops slowly, over time. Conversely, someone who has had a stroke will show a relatively sudden onset of symptoms. Also, the person who has had a stroke will usually show some improvement in symptoms with the aid of speech-language therapy, whereas the person with PPA will not improve significantly. The person with PPA can continue to perform routine self-care tasks, and even to be successfully employed, for some time after they begin to show changes in their communication skills. The precise symptoms that a person displays will vary, depending on what portion of the brain is most affected. However, here are some of the more common indicators:
- Hesitations in speech as the person struggles to find the word he wants to say
- Difficulty naming objects
- Difficulty understanding both spoken and written forms of language
- Errors in the use of word endings, pronouns, conjunctions, and word tenses
- Difficulty understanding word meanings
- Errors in spelling
PPA often begins with the person having difficulty with the formation of words, and his speech may sound slurred or indistinct. As the disease progresses, the person will eventually become almost completely mute. Typically, comprehension of language will remain intact until the latter stages of the disease. Less common is a form of the disease that starts out with word-finding difficulties, leaving articulation (pronunciation) relatively intact.
Often, the person with PPA will respond differently in dissimilar situations. For example, he may experience increased difficulty in high-stress situations or when he needs to use more specialized terminology, than when conversing with close friends. It’s also possible that written language may be impaired to a lesser degree than spoken language, or vice versa.
PPA is characterized by a shrinking of that portion of the left hemisphere of the brain that controls language. There may be scar tissue, and abnormal proteins may be present as well.
Persons who have learning disabilities may be at increased risk for development of PPA, possibly because both conditions involve the use of language. There are also some rare genetic malformations that can place a person at risk for the disease, especially if they have other family members who have it. One study showed that men who have a vasectomy are at increased risk, but this research has not been replicated.
The individual with PPA will generally lose the ability to speak at all, usually within about ten years of the onset of the disease. Eventually, other cognitive abilities may be affected as well, and the person may lose the ability to care for himself. Understandably, depression is common.
As with other forms of dementia, there is no one specific test that can be used to determine that a person has PPA. Diagnosis typically involves ruling out other disorders that may produce similar symptoms. (There are some other forms of dementia for which communication difficulties are often the first, or primary, symptom.) These tests will generally include an evaluation by a speech-language pathologist, who can also assist in measuring cognitive skills. It is important that this cognitive testing be done in such a way that results are not impacted by the person’s communication difficulties. Blood tests can rule out other possible disorders such as infections and metabolic deficiencies. And brain imaging tests can identify the presence of brain damage due to a stroke or a tumor.
Some medications used in the treatment of Alzheimer’s disease have been used with persons who have PPA. However, these have not proven to be effective, and no other drugs have as yet been identified to alleviate symptoms of the disease. Research is on-going. Speech and language therapy has definite benefits, specifically with helping the person learn to compensate for his impaired ability to communicate. It is also vitally important that the person’s family and caregivers learn to provide support by paying close attention to the impaired person, providing feedback and requesting clarification, providing more time for communication, and using gestures and other aids to increase comprehension. Loss of the ability to communicate is often very traumatic, and others will need to assume more of the burden of assuring that the person is making his/her needs known.