Continuing Education Activity
Broca aphasia is a non-fluent aphasia in which the output of spontaneous speech is markedly diminished and there is a loss of normal grammatical structure. Specifically, small linking words, conjunctions, such as and, or, and but, and the use of prepositions are lost. Patients may exhibit interjectional speech where there is a long latency, and the words that are expressed are produced as if under pressure. The ability to repeat phrases is also impaired in patients with Broca aphasia. Despite these impairments, the words that are produced are often intelligible and contextually correct. In pure Broca aphasia, comprehension is intact. Patients with Broca aphasia are often very upset about their difficulty communicating. This activity examines when Broca aphasia should be considered on differential diagnosis and the workup and treatment for this condition. This activity highlights the role of the interprofessional team in caring for patients with this condition.
Objectives:
- Describe the key clinical findings in patients with Broca aphasia.
- Describe the location of a lesion that may lead to Broca aphasia.
- Describe the management options for patients with Broca aphasia.
- Explain the importance of improving care coordination, with particular emphasis on communication between interprofessional medical teams, to enhance prompt and thorough delivery of care to patients with Broca aphasia.
Introduction
Aphasia is a term used to describe a disturbance in the ability to use symbols (written or spoken) to communicate information and is categorized into two types: expressive aphasia or receptive aphasia. These two types of aphasia can occur together. This article discusses Broca aphasia (also called expressive aphasia). Broca aphasia was first described by the French physician Pierre Paul Broca in 1861. A mild form of this condition is termed dysphasia. Aphasia/dysphasia should be distinguished from dysarthria which results from impaired articulation. Dysarthria, as opposed to aphasia, is a motor dysfunction due to disrupted innervation to the face, tongue, or soft palate that results in slurred speech but intact fluency and comprehension. Aphasia is typically considered a cortical sign. Its presence suggests dysfunction of the dominant cerebral cortex. [1][2][3]
Etiology
The most common cause of Broca aphasia is a stroke involving the dominant inferior frontal lobe or Broca area. A stroke in Broca area is usually due to thrombus or emboli in the middle cerebral artery or internal carotid artery. Other causes of Broca aphasia include traumatic brain injury, tumors, and brain infections. Aphasia is a symptom of degenerative dementing illnesses such as Alzheimer disease. With dementing illness, patients develop gradual progressive language deficits as opposed to a sudden onset of loss of language function that is seen in an ischemic stroke.[4]
Epidemiology
Data on the incidence of Broca aphasia are limited. In the United States, approximately 170,000 new cases of aphasia related to stroke occur annually.[5]
Pathophysiology
Broca area is a region in the inferior frontal lobe of the dominant hemisphere of the brain made up of Brodmann area 44 and 45. Language function lateralized to the left hemisphere in 96% to 99% of right-handed people and 60% of left-handed people. Various pathways connect Broca area to the frontal lobe, basal ganglia, cerebellum, and contralateral hemisphere.
As a result of a lesion in Broca area, there is a breakdown between one's thoughts and one's language abilities. Thus, patients often feel that they know what they wish to say but are unable to produce the words. That is, they are unable to translate their mental images and representations to words. This affects the normal fluency of speech. The loss of language function may be because Broca area serves a role in ordering sounds into words, and words into sentences, and thus creates relationships between linguistic elements.
History and Physical
Broca aphasia is non-fluent aphasia. The output of spontaneous speech is markedly diminished. There is a loss of normal grammatical structure (agrammatic speech). Specifically, small linking words, conjunctions (and, or, but), and the use of prepositions are lost. As an example, a sentence like "I took the dog for a walk." may become "I walk dog." Patients can exhibit interjectional speech where there is a long latency, and the words that are expressed are produced as if under pressure. The ability to repeat phrases is also impaired. Despite these impairments, the words that are produced are often intelligible and contextually correct. In pure Broca aphasia, comprehension is intact.
Patients with Broca aphasia are often very upset about their difficulty communicating. This may be due to the deficit itself or may be due to damage to adjacent frontal lobe structures which control the inhibition of negative emotions. Broca aphasia can accompany other neurological deficits such as right facial weakness, hemiparesis or hemiplegia, and apraxia.
Evaluation
Bedside examination of a patient with suspected aphasia includes assessments of fluency, the ability to name objects, repeat short phrases, follow simple and complex commands, read, and write. Formal neuropsychological testing may be helpful in determining the type and severity of the language deficit. Neuroimaging (CT, MRI, fMRI, PET or SPECT) may be required to localize and diagnose the cause of aphasia. Patients should also be screened for depression as this is also common in Broca's aphasia. [6]
Treatment / Management
Broca aphasia often has a devastating effect on the ability of individuals to carry out their normal activities. It affects the patient's ability to communicate and often leads to loss of productivity and vocation and can also lead to social isolation.[7][8][9]
Currently, there is no standard treatment for Broca aphasia. Treatments should be tailored to each patient's needs. Speech and language therapy is the mainstay of care for patients with aphasia. It is essential to provide aphasic patients a means to communicate their wants and needs, so these may be addressed. Often this is done by providing a board with various objects so that the patient can point to the object that they want. Involvement of a speech therapist, neuropsychologist, and neurologist in the development of a care plan for the patient with Broca aphasia is very helpful in obtaining a good outcome. One innovative treatment option for patients with Broca aphasia is melodic intonation. Melodic intonation relies on the fact that musical ability is often spared in Broca aphasia. Thus, the speech therapist encourages the patient with poor speech production to try to express their words with musical tones. This approach has shown promise in clinical trials.
Medical treatment of aphasia is currently under investigation in clinical trials. Drug therapies have included catecholaminergic agents (bromocriptine, levodopa, amantadine, dexamphetamine), piracetam and related compounds, acetylcholine esterase inhibitors, and neurotrophic factors. Previous studies have been small, and further studies are needed to determine the efficacy of these pharmacological agents. Also, transcranial magnetic stimulation and transcranial direct stimulation trials for aphasia are currently underway.
When the cause of Broca aphasia is a stroke, recovery of language function peaks within two to six months, after which time further progress is limited. However, patients should be encouraged to work on speech production, because cases of improvement have been seen long after a stroke. There are commercial software products available that claim to improve language function, but for the most part, these have not been rigorously tested in randomized clinical trials.
It is important to address issues of post-stroke depression and post-stroke cognitive impairment, as well as disorders of executive function, awareness, neglect, and hemiparesis during the rehabilitation process to optimize the outcome for an individual patient. Family and social support are extremely important to keep patients with language deficits engaged in social and leisure activities which can greatly influence the aphasic patient’s quality of life.
Differential Diagnosis
- Anterior circulation stroke
- Central pontine myelinolysis
- Cerebral venous thrombosis
- Dementia in motor neuron disease
Pearls and Other Issues
When speaking to a patient with aphasia, it is important to maintain a normal rate and volume. Questions should be simple. It is preferable to ask yes or no questions rather than open-ended questions that require a lengthy answer.
Enhancing Healthcare Team Outcomes
Broca aphasia is often seen in patients with head trauma or a stroke. While the individual has preserved comprehension, they have trouble speaking fluently. These patients often undergo speech therapy but because of their other illnesses are often looked after by nurses. Hence, nurses need to be aware of this speech disorder. Individuals with this disorder may be able to read, but their writing ability may be limited. However, it is important to appreciate the fact that in Broca aphasia, there is a preservation of intellectual and cognitive functions.[10][6]
Some patients may recover functionally and be able to lead an independent life as long as they do not have other comorbidities or neurological deficits. The recovery after Broca aphasia is often many months or even years, especially if the cause was a stroke. Most people see mild improvement within the first six months, but full recovery can take years. The key is to educate the family members of caregivers who will be looking after the patients.[11]
Broca Aphasia