A right-handed accountant develops fluent speech with frequent word substitutions and paraphasias, poor repetition of spoken phrases, and preserved comprehension. MRI shows a lesion deep to the supramarginal gyrus of the dominant hemisphere. Which pathway is interrupted?

• A Corpus callosum splenium connecting occipital lobes
• B Uncinate fasciculus connecting orbitofrontal and temporal cortex
• C Optic radiations passing through the temporal lobe
• D Arcuate fasciculus connecting Wernicke and Broca areas ✓

Explanation

Conduction aphasia features fluent speech, good comprehension, and markedly impaired repetition, classically from interruption of the arcuate fasciculus linking Wernicke area in the superior temporal gyrus with Broca area via the supramarginal region. The uncinate fasciculus links frontal and temporal limbic regions, optic radiation damage causes field defects, and splenial lesions cause disconnection syndromes such as alexia without agraphia, none of which produce isolated repetition failure.

Reference: Gray's Anatomy, 42nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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