Which finding would most strongly indicate right-hemisphere involvement rather than left-hemisphere language-area damage?

• A. Impaired repetition
• B. Fluent aphasia
• C. Prosopagnosia
• D. Agrammatism

Answer: (C)

Language and face recognition rely on different brain networks that are largely lateralized. The left hemisphere is typically dominant for language, while recognizing faces depends more on right-hemisphere regions, especially in the ventral visual processing stream.

So a deficit in recognizing familiar faces—prosopagnosia—points to problems in the right hemisphere’s face-processing areas rather than the left-side language network. Impaired repetition, fluent aphasia, and agrammatism all reflect disruption of left-hemisphere language areas: repeating spoken language taps phonological processing in left perisylvian circuits; fluent aphasia and agrammatism are classic left-hemisphere language deficits. Therefore prosopagnosia most strongly indicates right-hemisphere involvement.