Role of Cerebrospinal Fluid Biomarkers and (18)F-florbetapir PET Imaging in the Diagnosis of Primary Progressive Aphasia: A Retrospective Analysis

The use of biomarkers has recently supported the association between Alzheimer’s disease (AD) pathology and the logopenic variant of primary progressive aphasia (PPA). We aim to investigate possible differences in cerebrospinal fluid (CSF) biomarker concentrations in the three PPA variants, and to assess any agreement between CSF biomarkers and (18)F-florbetapir PET. A group of 10 PPA were retrospectively enrolled. Patients with logopenic variant (lvPPA) showed different levels of Aβ1-42 and p-tau compared to nonfluent/agrammatic and semantic variants (nfv/svPPA). All nfv/svPPA patients had negative amyloid PET. Among the lvPPA group, a negative amyloid PET was found only in one patient, who was also the only one to display a normal CSF. Thus, this small cohort appeared to display an excellent agreement between CSF and (18)F-florbetapir PET and suggest that these examinations may have the same validity in detecting in vivo evidence of AD pathology in PPA clinical variants.