Classification of primary progressive aphasia and its variants

TLDR

Criteria for the three PPA variants—nonfluent/agrammatic, semantic, and logopenic—were developed by an international group of investigators who convened on three occasions to operationalize earlier clinical descriptions. The article proposes a standardized classification of PPA and its three variants to improve case reporting and research reliability, and it plans future collaborations to link these syndromes with biomarkers for deeper clinicopathologic insight. Patients are diagnosed with PPA and classified into variants by specific speech and language features; the classification can be refined as imaging‑supported or with definite pathology when atrophy patterns or pathologic/genetic data are available, with recommendations and assessment tasks listed. These recommendations have been widely agreed upon by a large group of experts and should be used to ensure consistency of PPA classification in future studies.

Abstract

This article provides a classification of primary progressive aphasia (PPA) and its 3 main variants to improve the uniformity of case reporting and the reliability of research results. Criteria for the 3 variants of PPA--nonfluent/agrammatic, semantic, and logopenic--were developed by an international group of PPA investigators who convened on 3 occasions to operationalize earlier published clinical descriptions for PPA subtypes. Patients are first diagnosed with PPA and are then divided into clinical variants based on specific speech and language features characteristic of each subtype. Classification can then be further specified as "imaging-supported" if the expected pattern of atrophy is found and "with definite pathology" if pathologic or genetic data are available. The working recommendations are presented in lists of features, and suggested assessment tasks are also provided. These recommendations have been widely agreed upon by a large group of experts and should be used to ensure consistency of PPA classification in future studies. Future collaborations will collect prospective data to identify relationships between each of these syndromes and specific biomarkers for a more detailed understanding of clinicopathologic correlations.