What is Primary Progressive Aphasia?
What is Primary Progressive Aphasia?
Primary progressive aphasia (PPA) is a clinical dementia syndrome that is caused by neurodegenerative diseases including Alzheimer’s disease or a form of Frontemporal Lobar Degeneration. Below, we break down the PPA term to uncover how each word contributes to the definition of the syndrome.
Primary
Impairment is prominent in a single domain (language) with relative sparing of other domains early on (e.g., memory, personality and perception)
Progressive
The impairment will get worse over time, since it is caused by neurodegenerative disease
Aphasia
Refers to the language impairment that individuals experience
What are the symptoms of Primary Progressive Aphasia?
With primary progressive aphasia (PPA), the impairments in language appear gradually and get worse over time. In many instances, the person with PPA may be the first to notice that something is wrong and the changes in language may initially be attributed to stress or anxiety. Symptoms vary from one person to the next. The initial symptoms can include:
- Slowed speech
- Word-finding hesitations
- Sentences with abnormal word order in speech or emails
- Substitution of words (e.g., “table” instead of “chair”)
- Using words that are mispronounced or incomprehensible
- Difficulty understanding what words mean
- Difficulty following a conversation despite normal hearing
- Forgetting the names of familiar objects
- Inability to think of names of people, even though the person is recognized
- New impairments in spelling
Scientists have proposed three “subtypes” or “variants” of PPA based on initial symptoms. However, each person with PPA is unique and may have symptoms that do not fit neatly into one subtype or may have features of more than one subtype.
What Causes Primary Progressive Aphasia?
The symptoms of PPA occur when brain cells malfunction in language-related parts of the brain due to the accumulation of abnormal proteins. The underlying diseases causing PPA are called “neurodegenerative” because they cause gradually progressive brain cell death that cannot be attributed to other causes, such as head trauma, infection, stroke or cancer.
There are several types of neurodegeneration that can cause PPA. The three most commonly encountered types are:
- Frontotemporal lobar degeneration with abnormal tau protein accumulation (FTLD-tau)
- Frontotemporal lobar degeneration with abnormal TDP-43 accumulation (FTLD-TDP-43)
- Alzheimer’s disease (AD)
When abnormal proteins from AD or one of the forms of FTLD attack the language areas of the brain, PPA results. PPA is caused by AD in approximately 30 to 40 percent of cases and by one of the forms of FTLD in approximately 60 to 70 percent of cases.
The neuropathologic diagnosis of AD or one of the forms of FTLD can only be definitively determined at autopsy through examination of brain tissue with a microscope. However, scientists are working to identify biomarkers that can be used to make the diagnosis during life. Specialized brain scans using positron emission tomography (PET) and examination of cerebral spinal fluid (CSF), obtained through lumbar puncture, are two biomarkers currently being investigated to assist with determining the neuropathologic diagnosis. Scientists are working to identify additional reliable biomarkers.