Challenges in diagnosis of primary progressive aphasia.

Two 68-year-old men presented to the behavioral neurology clinic with memory complaints. The clinical picture was complicated by bilingualism and psychiatric comorbidities. Based on a combination of cognitive and language testing, 5-fluorodeoxyglucose positron emission tomography (FDG-PET), and/or magnetic resonance imaging (MRI) of the brain, both cases were initially diagnosed as having mild cognitive impairment (MCI). At follow-up, however, both cases' language profiles and neuroimaging had evolved to clearly indicate primary progressive aphasia (PPA) as the underlying condition rather than MCI. These cases underscore the importance of careful observation of clinical and neuroimaging data over time to reach an accurate diagnosis.