A 48-year-old woman is brought to the emergency department by her husband who is concerned with her lack of speech. He reports that she had been acting and speaking normally last night, but this morning did not respond to his conversation with her. Past medical history is significant for hypertension which is treated with hydrochlorothiazide. Vital signs are within normal limits. On physical examination, the patient is able to follow commands but is unable to speak.
A lesion in which of the following areas is the most likely cause of this patient's presenting symptom?
C) Inferior frontal gyrus
The patient is presenting with intact comprehension but impaired speech fluency. These symptoms are characteristic of expressive aphasia (Broca aphasia). Broca aphasia is caused by damage due to a lesion in the inferior frontal gyrus.
Answer A: Arcuate fasciculus, is incorrect. A lesion in the arcuate fasciculus would result in conduction aphasia. Conduction aphasia is characterized by intact comprehension, intact speech fluency, but impaired repetition.
Answer B: Cuneus, is incorrect. The cuneus is located in the occipital lobe, and a lesion there would result in deficits of the inferior visual field.
Answer D: Lingual gyrus, is incorrect. The lingual gyrus is located in the occipital lobe, and a lesion there would result in deficits of the superior visual field.
Answer E: Superior temporal gyrus, is incorrect. A lesion in the superior temporal gyrus would result in Wernicke aphasia (receptive aphasia). Wernicke aphasia is characterized by intact speech fluency but impaired comprehension and impaired repetition.
Key Learning Point
Broca, or expressive aphasia, is caused by damage to the inferior frontal gyrus.
