Primary progressive aphasia: causes and symptoms

One of the definitions of language is the capacity of the human being that he uses to express thoughts and feelings through words. Unfortunately, there are cases where this ability is cut short. One of these cases is aphasias, which are known to disable people for speech.

A rare type of aphasia is primary progressive aphasia (PPA). which is characterized by a progressive degeneration of speech ability in patients who maintain relatively intact the rest of their cognitive, instrumental or behavioral

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Causes of Primary Progressive Aphasia

Primary progressive aphasia (PPA), also called Mesulam's aphasia, is a neurodegenerative disease that materializes in a pathology of the linguistic domain.

This develops gradually and occurs in people who do not suffer any other alteration in the other areas. nor do they experience behavioral alterations or are limited in carrying out their activities everyday.

During the early stages of disease development, the patient is completely autonomous in terms of achieving of any task, however the degenerative course of this pathology ultimately leads to dementia widespread.

Contrary to what happens with secondary aphasias, primary aphasias seem to have no specific origin or cause. Even so, certain studies have attempted to detect the presence of atrophy patterns associated with this aphasia. Through the use of magnetic resonance imaging, characteristic atrophies of each of the types of aphasia have been observed:

• Inferior frontal and left insular atrophy in the grammatical APP
• Bilateral anterior temporal atrophy with left predominance in the semantic variant
• Left temporoparietal atrophy in the logopenic 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 of them is associated with a functional anatomical pattern.

These variants are the ungrammatical/non-fluent variant, the semantic variant, and the logopenic variant.

1. ungrammatical variant

This variant is characterized by being presented in the form of very difficult speech and a completely agrammatic production.

To clarify this concept, it should be noted that agrammatism consists of issuing short sentences with a very simple structure; omitting the functional expressions, which are those that serve as a link between the words.

The first symptom of the disease tends to be difficulty in planning speech.. Which begins to become slow and very laborious.

Certain minor grammatical errors can be detected early by applying oral production tests. In which patients with APP generally make some mistake in sentences with a complex grammatical construction.

2. semantic variant

Also called semantic insanity, in which the patient presents enormous difficulties when it comes to naming any object or thing; Presenting a 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 appear in understanding the meaning of objects. These difficulties when it comes to identifying and accessing knowledge occur regardless of the sensory modality in which the stimuli are presented.

Generally there is a gradual decrease in the set of knowledge that the patient has about the world around him.

3. logopenic variant

It is considered the least common variant of the three, which presents two characteristic features:

• Difficulty in accessing vocabulary
• Sentence repetition errors

The clearest way to exemplify this type of aphasia is to represent it as the constant sensation of “having something on the tip of the tongue”. The patient does not suffer from an agrammatism, but rather finds recurring difficulties when it comes to finding the words he is looking for; presenting, in addition, errors of a phonological type.

This last point leads us to suspect that patients suffering from primary progressive aphasia also have impaired phonological storage; since the comprehension of isolated words and short sentences is correct, but there are difficulties when interpreting long sentences.

Diagnosis: Mesulam criteria

There are two different stages when making a diagnosis of primary progressive aphasia:

1. Patients must meet the characteristics of Mesulam for APP without considering any specific variant.
2. Once the APP has been diagnosed, the variant will be determined by evaluating the linguistic cognitive processes.

Mesulam criteria for PPP

These criteria described by Mesulam in 2003 take into account both the diagnostic inclusion criteria and the exclusion criteria. These criteria are the following:

• The language becomes a slow and progressive speech. Both when it comes to naming objects, as well as in syntax or oral comprehension.
• Other activities and functions that do not involve intact communication skills.
• Aphasia as the most prominent deficit at the beginning of the disease. Although the rest of the psychological functions can be affected during the course of this, language is the most damaged from the beginning.
• APP is ruled out if there is a presence of aphasia-related stroke, tumor, or trauma in the patient's history.
• If there are strange behavioral changes that are more evident than the aphasic alteration, APP is ruled out.
• If there are important alterations in episodic memory, non-verbal memory or in visuospatial processes, APP will not be considered.
• When parkinsonian symptoms such as rigidity or tremor appear, APP is ruled out.

Treatment

There is no cure or medication for APP. However, there are speech therapy therapies that help improve and maintain the patient's communication skills.

These therapies focus the person's effort on compensating 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 APP can occur in a wide age range, it is more likely to occur in people between the ages of 50 and 70.. As previously mentioned, there is currently no cure for APP, so the prognosis for this disease is somewhat discouraging.

Once the disease has established itself, this aphasic disorder tends to progress in a way that ends up leading to severe cases of mutism. But unlike other dementias, the patient becomes dependent much later.

Regarding the presence of other additional deficits, language is the only clinical manifestation or, at least, the most predominant. But if there are cases of other alterations at the cognitive, behavioral, extrapyramidal level, etc. However, it is unknown how frequently generalized dementias appear during the course of the disease.