Tan's lesion location? Which brain region did Tan have lesions in?

• A. Lower region on left frontal lobe (Broca's area)
• B. Upper region on right frontal lobe
• C. Posterior region on left parietal lobe
• D. Left occipital lobe

Answer: (A)

Expressive language production is localized in Broca's area, the left inferior frontal gyrus. Tan’s classic case showed a severe impairment in speech output while comprehension was relatively intact, pointing directly to a lesion in the left frontal region where Broca’s area sits. This area is in the lower part of the left frontal lobe, and damage here leads to nonfluent, telegraphic speech with good comprehension, known as expressive aphasia. The other regional options wouldn’t produce this specific pattern: a lesion in the right frontal region is unlikely to disrupt language production in a typically dominant (left-dominant) hemisphere; a posterior left parietal lesion would affect different language or cognitive functions and not produce the hallmark expressive speech deficit; a left occipital lesion would mainly affect vision, not speech.