Clinical amyloid imaging in logopenic progressive aphasia.

The introduction of florbetapir (Amyvid) positron emission tomography biomarkers could dramatically change how we clinically evaluate young patients who present with nonamnestic cognitive complaints for possible Alzheimer disease (AD). Logopenic progressive aphasia (LPA) may be the most common example of this type of clinical problem. In most, but not all, cases, LPA is an early-onset AD variant presenting with language changes that can be difficult to distinguish from other progressive aphasias. We clinically evaluated 3 patients with LPA, in comparison with age-matched and severity-matched patients with typical amnestic AD, using florbetapir amyloid neuroimaging. The fluorodeoxyglucose-positron emission tomography scans of LPA patients revealed focal hypometabolism in the left temporoparietal areas, and the florbetapir scans were diffusely positive for the presence of amyloid deposition. The florbetapir scans did not differ in distribution between patients with LPA and those with typical amnestic AD. Clinical amyloid imaging, although lacking localizing value, is a major advance in the assessment of early-onset and nonamnestic patients for the presence of β-amyloid Alzheimer pathology.