In 1865, Paul Broca described patients of his who were characterized by the sudden lack of the ability to speak, and a right hemiparesis. He theorized that this was due to damage to a language area in the brain. Following the patients' death and post mortum examination, Broca demonstrated the region was in the left posterior frontal lobe, around the area of the operculum. Broca's discovery spawned the notion that the brain was laterilized and compartmentalized. Cerebral localization became a popular research topic as many new areas of specialization were discovered.
Broca's aphasia is characterized by nonfluent speech, few words, short sentences, any many pauses. The words that the patient can produce come with great effort and often sound distorted. The melodic intonation is flat and monopitched. This gives the speech the general appearance of a telegraphic nature, because of the deletion of functor words and disturbances in word order. Moreover, the repetition of words and phrases is impaired. However, aural comprehension for conversational speech is relatively intact. There is often an accompanying right hemiparesis involving the face, arm, and leg.
Here is an T2-MR image of a stroke which arrested the patient's speech. It comes from The Whole Brain Atlas at Harvard. The patient's left is on the right side of the image. Lesions causing Broca's aphasia can involve the frontal operculum and also the premotor and motor regions of the brain that lie behind and above Broca's area proper. Also, lesions deep within the white matter and the basal ganglia of the brain can produce a Broca-like aphasia. In general, the more extensive the involvement of the cerebrum, the poorer the prognosis for recovery following the stroke.
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