Work

Cognitive-linguistic skills in production of expository discourse: Insights from longitudinal changes and neural correlates in primary progressive aphasia

Year: 2025

Type: article

Abstract: BACKGROUND: Engaging in conversational and story-telling discourse involves an interplay of language and cognitive skills, including working memory, attention, and inference-making. Primary progressive aphasia (PPA) provides a model for exploring discourse, as both language and cognitive abilities change over time with changes in cortical atrophy. Here, associations between morphosyntactic discourse skills and patterns of cortical atrophy are measured over time in nonfluent (nfv), logopenic (lv) and semantic (sv) variants of PPA. METHOD: Participants were 27 individuals with nfvPPA (M = 66.6 years ± 8.3), 30 lvPPA (M = 66.7 ± 7.3), 33 svPPA (M = 64.8 ± 6.7), and 36 healthy controls (HC; M = 65.5 ± 6.8). Picture descriptions were analysed for word density and diversity, sentence complexity, well-formedness, and fluency annually for up to three timepoints. Associations between language measures and cortical thickness on structural MRI scans were analysed. RESULTS: At timepoint 1, nfvPPA performed below other groups on most measures; lvPPA were differentiated from svPPA on fluency measures only. Longitudinally, utterance length declined in all variants. For nfvPPA, this was linked with reduced sentence complexity and cortical atrophy in regions engaged by higher attentional demand. For lvPPA, it was linked with increasing grammatical errors and atrophy extending into perisylvian language network. No associations were identified for svPPA. CONCLUSIONS: Findings provide insight into how discourse production is underpinned by a network that extends beyond classic language regions, with morphosyntactic elements of discourse associated in part with regions involved in domain-general cognitive skills such as error-monitoring and elaborative encoding. Findings can also inform assessment, prognosis, and intervention for communication through the PPA disease course.

Source: Cortex

DOI: 10.1016/j.cortex.2025.11.011