What Is Broca’s Aphasia?
Also, known as expressive aphasia or non-fluent aphasia, it is a type of aphasia in which there is a significant decrease in the output of spontaneous speech. Patients with this type of aphasia are unable to use small linking words like as, and, but, etc., which results in loss of grammatical structure during speech.
They may take long pauses during speaking and when they do express themselves, the words come out as if under pressure. They are unable to repeat phrases and construct a complete sentence, but the words they do produce are intelligible and contextually correct which indicates that their comprehension is intact.
Both Broca's aphasia and dysarthria have similar signs but the latter is a motor dysfunction that is caused due to disrupted innervation to the tongue, soft palate, face, etc. Broca’s aphasia on the other hand results from damage to the Broca area in the brain.
What Is Broca Area?
It is a region located in the cerebral cortex of the dominant hemisphere at Brodmann areas 44 and 45. The Broca area is connected to the frontal lobe, basal ganglia, cerebellum, and the contralateral hemisphere through various pathways. The dominant hemisphere is thought to be opposite to one’s handedness, which means a right-handed individual will have a left dominant hemisphere and a left-handed individual will have a right dominant hemisphere. In recent times, it is observed that the Broca area is on the left side of the cerebral hemisphere in the majority of individuals regardless of their handedness. Since it is present in the lateral cortex of the cerebral hemisphere, it receives blood supply from the superior division of the middle cerebral artery.
Although the exact mechanism is unclear, the primary function of the Brocha area is comprehension and language production which include:
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Semantics is responsible for understanding the meaning of words.
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Phonology is responsible for producing sounds in a language.
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Language repetition.
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Gesture production.
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Sentence grammar.
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Fluidity.
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Interpretation of others’ actions.
What Causes Broca’s Aphasia?
The different causes of Broca’s aphasia are:
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Ischemic stroke in the Broca area due to a thrombus (blood clot) or emboli in the middle cerebral artery or internal carotid artery that reduces the blood supply to the region.
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Traumatic brain injury involving the Broca area of the brain.
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Brain infections.
As a result of these conditions, there is a breakdown between the thoughts and the associated language abilities. This causes a sudden onset of speech and language disorders as opposed to other types of aphasia that are caused due to degenerative dementing illnesses like Alzheimer’s.
The patients feel like they know what they want to say, but are unable to produce the exact words that express their feelings, thoughts, and opinions.
What Are the Signs and Symptoms of Broca's Aphasia?
The following are the symptoms of Broca’s aphasia-
Telegraphic Speech - It is a type of speech that contains important content but is incomplete. The sentence lacks prepositions, conjunctions, and other words that have grammatical significance. For example- The sentence “I took the dog for a walk” becomes “I walk dog”.
Problems With Repetition - In order to successfully repeat a sentence, the brain needs the following structure-
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Bronca area.
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Wernicke’s area.
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Arcuate fasciculus.
Since the Bronca area is damaged in these patients, they lose the ability to repeat.
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Partial Loss of Comprehension - Patients with Broca’s aphasia are completely aware of their deficits due to an intact Wernicke’s area which is responsible for comprehension.
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Stuttering - Also known as stammering, patients with Broca’s aphasia have unintended prolongations in their speech similar to stuttering. But the latter defers from the former in the aspect of repetition which is a characteristic feature of stuttering.
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Transient Mutism - Mutism is an inability to speak, in patients with Broca’s aphasia this inability is a combination of defective phonation and vocalization.
Unlike Alzheimer’s patients, who are unaware of their condition, patients with Broca’s aphasia are completely aware of their inabilities which often leads to frustration and depression.
How Is Broca’s Aphasia Diagnosed?
After obtaining a detailed medical history, the clinician will perform a set of comprehensive language tests to form an initial diagnosis. These tests include studying speech, naming, repeating, comprehension, reading, and writing.
Once the initial diagnosis is made, the clinician will request the following investigations to confirm the diagnosis:
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Computed Tomographic (CT) Scan - This is an imaging test that uses X-rays and a computer to make detailed images of the brain.
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Magnetic Resonance Imaging (MRI) - A diagnostic procedure that uses a combination of magnets, radiofrequency, and computers to produce images of the brain.
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Positron Emission Tomography (PET) Scan - This is also a computer-based imaging technique that uses radioactive substances to produce images.
How Is Broca’s Aphasia Treated?
Currently, there is no standard treatment for this condition, treatment is often tailored based on the individual patient’s needs. A multidisciplinary team containing a speech therapist, a neurologist, and a neuropsychologist develops the care plan after careful consideration. Apart from the speech and language, treatment is also focused to address the following issues:
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Post-stroke depression.
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Post-stroke cognitive impairment.
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Disorders of executive function.
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Awareness.
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Neglect.
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Hemiparesis (partial paralysis or muscle weakness on one side of the body).
This kind of approach optimizes the outcomes for each individual patient. In these patients, recovery peaks within two to six months after starting the treatment, however, they are encouraged to work on their speech production post-treatment. A new innovative treatment that has gained recent attention is melodic intonation. It is based on the fact that musical ability is not affected in patients with Broca’s aphasia, this allows the patients to express their words in musical tones, this approach has shown promising results in clinical trials.
Drug therapy for aphasia is still under trial, the drugs currently being evaluated are:
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Catecholaminergic agents like Bromocriptine, Levodopa, Amantadine, etc.
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Piracetam and related compounds.
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Acetylcholinesterase inhibitors.
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Neurotrophic factors.
Other trials include transcranial magnetic stimulation and transcranial direct stimulation, which are currently underway and yet to be approved.
Conclusion
Patients with Broca’s aphasia have comprehension but they lack the ability to speak fluently. The recovery takes months to years but most of them are able to perform functionally and lead an independent life. The family members and caregivers play an important role in the recovery especially if the cause of the aphasia was a stroke.
