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The following is a summary of “Primary Progressive Aphasia Lacking Core Features of Nonfluent and Semantic Variants: Clinical, Neuroimaging, and Neuropathologic Feature,” published in the October 2024 issue of Neurology by Watanabe et al. 

Primary progressive aphasia (PPA) criteria from 2011 may not fully capture the logopenic variant (lvPPA) features, prompting further investigation.  

Researchers conducted a retrospective study examining clinical, neuroimaging, and neuropathologic features of PPA that lack key traits of nonfluent or semantic variants.  

They analyzed data from 2 observational cohort studies in which patients with PPA were recruited at Mayo Clinic. Patients were categorized based on their performance on 2 cardinal features—repetition and comprehension—into 4 groups, pure-LPA (poor repetition, acceptable comprehension), Wernicke-like (poor in both), anomic-like (acceptable in both), and transcortical sensory aphasia-like (TCSA-like) (acceptable repetition, poor comprehension).  

The results showed that 73% of patients had preserved repetition ability (anomic-like and transcortical sensory aphasia-like), while 27% had impaired repetition (pure-logopenic variant PPA and Wernicke-like). Among 31 patients followed for 1 year, the anomic-like subgroup was identified as a prodromal state for the pure-logopenic and transcortical sensory aphasia-like subgroups, which were considered prodromal for the Wernicke-like subgroup. All groups exhibited left temporoparietal atrophy and/or hypometabolism on neuroimaging. Furthermore, severe hypometabolism in the left superior temporal lobe was associated with repetition ability in the repetition-impaired groups. Approximately 70% of the patients had Alzheimer’s disease (AD) pathology, while 53% of the anomic-like subgroup had AD. The remaining 47% showed Pick disease (7%), frontotemporal lobar degeneration with TDP-43 pathology (20%), or Lewy body disease (20%).  

 They concluded that clinical heterogeneity in AD-related aphasia can be reconceptualized as a spectrum, incorporating lvPPA and the subgroups. 

Source: neurology.org/doi/10.1212/WNL.0000000000209924