Primary progressive aphasia: from syndrome to disease

Abstract

Introduction: Primary progressive aphasia (PPA) is a clinical syndrome characterised by a progressive decline in language and speech of neurodegenerative origin. Major breakthroughs made in recent years have lent us a better understanding of this syndrome, which may be the first manifestation of any of a number of neurodegenerative diseases.

Development: We reviewed the main aspects of PPA epidemiology, clinical manifestations, diagnosis, aetiology and treatment. Most cases manifest sporadically and the typical age of onset is between 50 and 70 years. Three clinically distinct variants have been described: nonfluent or agrammatic PPA, semantic PPA and logopenic PPA. Each of these variants tends to be associated with specific histopathological findings, but clinical diagnostic methods are imperfect predictors of underlying pathology. Anatomical and functional neuroimaging can provide useful biomarkers. Several treatments have been proposed, and while no clear benefits have been demonstrated, acetylcholinesterase inhibitors may be useful, especially in the logopenic variant.

Conclusions: PPA is an emerging syndrome which may be more prevalent than we might expect. It was previously listed as part of the frontotemporal dementia spectrum, and it is also related to Alzheimer disease. Clinical diagnosis, complemented by a biomarker evaluation, may predict the underlying pathology, which in turn will improve treatment possibilities.

Keywords: Afasia progresiva primaria; Alzheimer disease; Degeneración frontotemporal lobar; Demencia frontotemporal; Demencia semántica; Enfermedad de Alzheimer; Frontotemporal dementia; Frontotemporal lobar degeneration; Logopenic; Logopénica; Primary progressive aphasia; Semantic dementia; Tauopathies; Taupatías.