From the Guidelines
Primary progressive aphasia (PPA) is a subset of frontotemporal dementia (FTD), with the semantic variant (svPPA) and nonfluent/agrammatic variant (nfvPPA) being primarily associated with frontotemporal lobar degeneration pathology. The relationship between PPA and frontotemporal aphasia is complex, with PPA being a language-led neurodegenerative dementia that can be divided into three major syndromes: semantic variant (svPPA), nonfluent/agrammatic variant (nfvPPA), and logopenic variant (lvPPA) 1.
Key Characteristics of PPA Variants
- The semantic variant (svPPA) is characterized by difficulties in word retrieval and understanding word meaning, and is primarily associated with frontotemporal lobar degeneration pathology (specifically TDP-43 type C) 1.
- The nonfluent/agrammatic variant (nfvPPA) is characterized by motor planning or programming, known apraxia of speech (AOS), and/or difficulties with grammar (agrammatism), and is usually associated with frontotemporal lobar degeneration pathology (most will have a primary tauopathy such as progressive supranuclear palsy or corticobasal degeneration) 1.
- The logopenic variant (lvPPA) is commonly associated with Alzheimer’s disease pathology and results in difficulties in word retrieval and phonological working memory 1.
Clinical Implications
The understanding of PPA as a subset of FTD, with specific variants associated with frontotemporal lobar degeneration pathology, has significant implications for diagnosis, management, and treatment of these conditions. Accurate diagnosis and characterization of PPA variants are crucial for developing effective communication interventions and supportive care strategies. As noted in a recent study, people with PPA and their families have reported that measures used have not always focused on the outcomes that are important to them, highlighting the need for a more patient-centered approach to care 1.
From the Research
Relationship Between Primary Progressive Aphasia and Frontotemporal Aphasia
- Primary progressive aphasia (PPA) is a clinical syndrome characterized by a progressive decline in language and speech of neurodegenerative origin, which may be related to frontotemporal dementia (FTD) pathology 2, 3, 4.
- PPA has been recognized as a syndrome distinct from the usual pattern of language deterioration in Alzheimer's disease and is typically more related to the pathology of frontotemporal dementia (FTD) 2.
- The syndromes of primary progressive aphasia have become more complex, divided into three subtypes: progressive nonfluent aphasia (PNFA), semantic dementia (SD), and logopenic/phonological progressive aphasia (LPA) 2, 5, 6.
- PNFA is usually, but not always, associated with FTD pathology and often evidence of a tau mutation, while SD is usually associated with FTD of the ubiquitin staining or progranulin (TAR-DNA) mutation type 2.
- Patterns of atrophy on magnetic resonance imaging (MRI) generally conform to these subtypes, with PNFA associated with left frontal and insular atrophy, SD associated with bilateral temporal atrophy, and LPA associated with left superior-posterior temporal and parietal atrophy 2.
- PPA is an emerging syndrome which may be more prevalent than expected, and it is also related to Alzheimer's disease, with clinical diagnosis and biomarker evaluation potentially predicting the underlying pathology 3, 4.