In a 56-year-old patient with language deficits and normal brain imaging and no history of brain injury, which diagnosis is most likely?

• A. dementia
• B. mild cognitive impairment
• C. primary progressive aphasia
• D. stroke

Answer: (C)

The situation points to a language-dominant, progressive neurodegenerative syndrome. Primary progressive aphasia presents with steadily worsening language difficulties that predominate early on, while memory and other cognitive abilities can remain relatively preserved at the outset. Brain imaging can appear normal in the early stages because the disease mainly affects language regions before widespread atrophy becomes evident, fitting a middle-aged person with language deficits but no history of brain injury or detectable lesions.

This pattern distinguishes it from other options. Stroke typically causes sudden, focal neurological signs with an acute lesion on imaging. Dementia involves broader, multi-domain cognitive decline and usually shows more extensive brain changes over time. Mild cognitive impairment is a transitional state with subtle deficits, often in memory, rather than isolated, progressive language impairment.