A patient has fluent speech but poor comprehension with paraphasias; which aphasia and where is the lesion?

• A. Wernicke's aphasia; left posterior superior temporal gyrus
• B. Broca's aphasia; left inferior frontal gyrus
• C. Global aphasia; left perisylvian cortex
• D. Anomic aphasia; left inferior temporal gyrus

Answer: (A)

When speech flows nicely but understanding is impaired and paraphasias are present, the pattern points to a receptive language deficit. This is characteristic of Wernicke's aphasia, a disorder of language comprehension and semantic processing. The typical lesion is in the left posterior superior temporal gyrus, the region that integrates auditory language input and meaning. Because this area is damaged, a person can produce fluent, well-formed-sounding speech, but the content often lacks meaning and includes paraphasias, and comprehension of spoken language is markedly reduced. Repetition is commonly affected as well because the ability to map heard words onto their meaning is disrupted.

Other syndromes don’t fit this profile as neatly: Broca’s aphasia involves nonfluent, effortful speech with relatively preserved comprehension, linked to the left inferior frontal gyrus. Global aphasia would show widespread impairment of both expression and comprehension due to extensive perisylvian damage. Anomic aphasia features fluent speech and relatively good comprehension but persistent word-finding problems, typically with damage to temporal-parietal regions.