Primary Progressive Aphasia (PPP)-Causes and Symptoms
One of the definitions of language is that of the human being’s own capacity to express thoughts and feelings through words. Unfortunately, there are cases in which this ability is truncated. One such case is aphasia, which is known to disable people from speaking.
A rare type of aphasia is primary progressive aphasia (PPP) which is characterized by a progressive degeneration of speech ability in patients who maintain relatively intact the rest of their cognitive, instrumental or behavioural skills.
Causes of primary progressive aphasia
Primary progressive aphasia (PPP), also called Mesulam aphasia, is a neurodegenerative disease that results in a pathology of the linguistic domain .
It develops gradually and occurs in people who do not suffer any other alteration in the other cognitive areas, nor do they experience behavioural alterations or are limited in their daily activities.
During the first stages of development of the disease, the patient is completely autonomous in terms of achieving any task, however the degenerative course of this pathology finally leads to generalized dementia.
Unlike secondary aphasias, primary aphasias appear to have no specific origin or cause. Still, some studies have attempted to detect the presence of atrophy patterns associated with this aphasia. Using magnetic resonance imaging, characteristic atrophies of each type of aphasia have been observed:
- Lower frontal and left insular atrophy in grammatical PPP
- Bilateral anterior temporal atrophy with left predominance in the semantic variant
- Left temporoparietal atrophy in the speech therapy variant
Types of primary progressive aphasia
Researchers in this field detail three variants of this type of aphasia in which, as mentioned in the previous section, each is associated with a functional anatomical pattern.
These variants are the agramatical/non-fluent variant, the semantic variant and the logopenic variant.
1. Agramatical variant
This variant is characterized by very difficult speech and a completely agrammatic production.
To clarify this concept, it should be noted that agramaticism consists of the emission of short sentences with a very simple structure; omitting functional expressions, which are those that serve as a link between words.
The first symptom of the disease tends to be difficulty in planning speech . This starts to become slow and very laborious.
Certain minor grammatical errors can be detected early by applying oral production tests. In which APP patients usually make some mistake in sentences with a complex grammatical construction.
2. Semantic variant
Also called semantic dementia, in which the patient presents enormous difficulties when naming any object or thing ; presenting normal performance in the rest of the linguistic functions, at least at the beginning of the disease.
During the course of the disease, semantic memory gradually deteriorates, while other difficulties in understanding the meaning of objects appear. These difficulties in identifying and accessing knowledge occur regardless of the sensory mode in which the stimuli are presented.
Generally, there is a gradual decrease in the patient’s knowledge of the world around them.
3. Logopenic variant
It is considered the least common of the three variants, which have two characteristic features:
- Difficulty in accessing vocabulary
- Errors in sentence repetition
The clearest way to exemplify this type of aphasia is to represent it as the constant feeling of “having something on the tip of your tongue”. The patient does not suffer from an agramaticism, but rather finds recurrent difficulties in finding the words he or she is looking for; presenting, moreover, phonological errors .
This last point raises the suspicion that patients suffering from primary progressive aphasia also present a deterioration in the phonological store; since the understanding of isolated words and short phrases is correct, but difficulties appear when interpreting long phrases.
Diagnosis: Mesulam criteria
There are two distinct stages when making a diagnosis of primary progressive aphasia:
- Patients should meet the characteristics of Mesulam for PPP without considering any specific variant.
- Once the PPP has been diagnosed, we will move on to determine which variant it is by evaluating the linguistic cognitive processes.
Mesulam Criteria for PPP
These criteria described by Mesulam in 2003 take into account both diagnostic inclusion and exclusion criteria. These criteria are as follows:
- The language becomes a speech in slow and progressive. Whether in naming objects, in syntax or in oral comprehension.
- Other activities and functions that do not involve intact communication skills.
- Aphasia as the most prominent deficit at the onset of the disease. Although all other psychological functions can be affected during the course of the disease, language is most impaired from the outset.
- APP is ruled out if there is a stroke, tumor, or trauma related to aphasia in the patient’s history.
- If there are strange behavioural changes more evident than the aphasic alteration, PPP is ruled out.
- If there are significant alterations in episodic memory, non-verbal memory or visuospatial processes will not be considered PPP.
- If Parkinsonian symptoms such as stiffness or tremor appear, PPP is ruled out.
Treatment
There is no cure or medication for PPP. However, there are speech therapies that help improve and maintain the patient’s ability to communicate.
These therapies focus on the person’s efforts to compensate for the deterioration of language skills . In this way, although the evolution of the disease cannot be stopped, the condition can be controlled.
Evolution and prognosis
Although PPP can occur in a wide range of age groups, it is more likely to occur in people between 50 and 70 years old . As mentioned above, there is no cure for PPP at the moment, so the prognosis for this disease is somewhat demoralizing.
Once the disease is established, this aphasic disorder tends to progress in ways that eventually lead to severe cases of mutism. But unlike other dementias, the patient becomes dependent much later.
As for the presence of additional deficits, language is the only or at least the most predominant clinical manifestation. But if there are cases of other alterations at the cognitive, behavioural, extrapyramidal level, etc. However, it is not known how often generalized dementias appear during the course of the disease.