After a CVA, a patient shows intact grammar and prosody but sentences that are meaningless with paraphasic errors, plus poor repetition and naming. Which brain region is most likely lesioned?

• A. Left posterior superior temporal gyrus
• B. Left inferior frontal gyrus
• C. Left superior frontal gyrus
• D. Left inferior parietal gyrus

Answer: (A)

The described pattern fits Wernicke's aphasia, where speech is fluent and prosody is preserved but content is meaningless and filled with paraphasias, and there are deficits in repetition and naming. This happens when the left posterior superior temporal gyrus is damaged, a region essential for mapping sounds onto meanings and for retrieving lexical information. Because comprehension is impaired, the speech sounds fluent but lack meaningful content, and the ability to repeat or name is reduced.

If the lesion were in another language area, the symptoms would look different. Damage to the left inferior frontal gyrus (Broca’s area) typically causes nonfluent, telegraphic speech with relatively preserved comprehension. Lesions in the left superior frontal gyrus or left inferior parietal gyrus don’t produce this same fluent-with-paraphasias pattern, so they’re less likely explanations for the described symptoms.