Alzheimer and frontotemporal pathology in subsets of primary progressive aphasia

Subtyping PPA helps to predict AD versus frontotemporal lobar degeneration pathology at the group level. However, our results and the literature also indicate that no clinical predictor is completely reliable in individual patients. The inconsistent concordance of NFT distribution with the asymmetric atrophy and the nonamnestic phenotype also raises the possibility that the AD markers encountered at autopsy in PPA may not always reflect the nature of the initiating neurodegenerative process.