Broca's aphasia: symptoms and causes of this disorder

Since the brain controls or supervises a large part of the functions of our body, damage to different regions of this structure can cause very varied alterations. Aphasias are a type of language disorder that occurs as a result of lesions in areas of the brain related to language.

In this article we will describe symptoms and causes of Broca's aphasia, expressive, motor or production. This neuropsychological disorder consists of the alteration of expressive language as a consequence of damage to the frontal lobe, although listening comprehension is not necessarily affected, as in other types of aphasia.

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What is aphasia?

Aphasias are language disorders that appear due to lesions in certain regions of the brain, mainly due to head injuries and strokes, also called heart attacks or strokes. The term is based on classical Greek and translates as "inability to speak."

There are different types of aphasia that are characterized by idiosyncratic combinations of alterations in four linguistic domains:

verbal comprehension, oral expression, functional communication and literacy. Most of them share the presence of anomia, which consists of persistent difficulty in retrieving words from memory.

Other common signs and symptoms of aphasias are articulatory and comprehension deficits, reduced spontaneous language, inability to read and / or writing, dysprosodia (alterations in the tone and rhythm of speech) and the use of neologisms (in psychopathology, words that only have meaning for those who says them).

Therefore aphasias not only affect spoken language, but also written and mimicry, including sign language. This is because all these forms of communication depend on the same cognitive functions, related to brain structures and pathways that are damaged in aphasia.

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Symptoms and signs of Broca's aphasia

The basic signs of Broca's aphasia are related to the production of speech. People with this syndrome have severe difficulty finding words and articulating sentences fluently, and the prosody of speech is also affected, causing speech to be monotonous. Writing is equally affected.

In the context of this disorder it is often spoken of "telegraphic speech" to refer to the way of expressing themselves of those who suffer it: they take many pauses because they have many difficulties to articulate (or gesture) words that are not content, that is, they are communicated mainly through sequences of nouns and verbs.

The intensity of these symptoms depends on the severity of the injury; while in some cases only mild anomie appears, moderate reductions in expressive fluency and the phenomenon of "foreign accent", in others the person may be unable to utter any words. In most cases, at least the most formulaic expressions are retained.

Since the regions associated with Broca's aphasia are involved in motor skills, it is not surprising that the brain lesions that cause it also cause motor signs. Hemiparesis (paralysis in one half of the body), apraxia (deficit in purposeful movements) and dysarthria, which affects pronunciation.

In a synthetic way we can say that the main characteristics of Broca's aphasia are the following:

• Lack of fluency in spontaneous language
• Alterations in writing
• Maintenance of listening and reading comprehension
• Word repetition deficit
• Trouble remembering words, such as names of objects (anomie)
• Associated motor disorders (dysarthria, apraxia, hemiparesis)

Causes of this disorder

Broca's aphasia appears as a consequence of lesions in the anterior part of the brain, especially in the frontal lobe of the hemisphere left, which plays a more relevant role than the right in the execution of movements, including those that are necessary for speech and writing.

Although the name of the disorder is associated with Brodmann area 44, known as “Broca's area”, the damage that is limited to this brain region causes only mild linguistic and motor symptoms. The most serious manifestations appear when the lesion extends to surrounding areas, such as the anterior insula, the precentral gyrus, and the opercular region.

The most common cause of Broca's aphasia is ischemic stroke, which consist of the interruption of blood flow, and therefore of oxygen, to a certain area of ​​the brain. In this case, the regions affected by oxygen hypoperfusion are those mentioned in the previous paragraph.

With certain frequency the brain lesions that cause this type of aphasia are due to other reasons; the most frequent are head trauma, brain hemorrhages, the brain tumors located near the language areas and extradural hematomas (collections of blood or other fluids between the meninges and the skull).

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