Language Profile of Posterior Cortical Atrophy: A Comparative Study with Alzheimer's Disease Variants

ObjectiveThis study investigates language impairments in early-stage posterior cortical atrophy (PCA) patients, examining five language subdomains to resolve existing controversies and gaps in the literature. MethodsParticipants diagnosed with posterior cortical atrophy (PCA; n=105), typical Alzheimers disease (tAD; n=105), logopenic variant primary progressive aphasia (lvPPA; n=116) and healthy controls (HC; n=165) were selected from the National Alzheimers Coordinating Center (NACC) database. We utilized language tests from the Uniform Data Set and Frontotemporal Lobar Degeneration Module to assess different aspects of linguistic ability, including verbal fluency, reading, naming, semantics and repetition. ResultOur findings revealed a global decline in visual and non-visual language functions among PCA patients compared to HC, with no spared domains. Furthermore, we investigated specific language errors in reading and sentence repetition, and we found that PCA patients committed a mix of phonological, semantic and word omission errors. They were more impaired on irregular vs. regular word reading and more impaired on verb vs noun naming. Overall PCA patients showed less severe language deficits than lvPPA, except in single word comprehension and verb naming, where the opposite pattern was found. They also showed more impaired visual language impairments and similar non-visual language impairments in comparison to tAD. DiscussionThese findings highlight that language impairments in PCA extend beyond visual deficits, playing a key role in its clinical presentation. Recognizing these language issues is essential for differentiating PCA from tAD and lvPPA, where distinct patterns of impairment help refine diagnosis.