Exploring the Links Between Lexical Production and Track-Weighted Imaging in Middle-Aged Adults

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Clément GUICHET¹ (clement.guichet@univ-grenoble-alpes.fr), Arnaud Attyé², Elise Roger^1,3,4, Sophie Achard⁵, Martial Mermillod¹, Monica Baciu¹; ¹Univ. Grenoble Alpes, CNRS UMR 5105 LPNC, ²GeodAIsics, Grenoble, France, ³Institut Universitaire de Gériatrie de Montréal, Communication and Aging Lab, ⁴Faculty of Medicine, University of Montreal, ⁵LJK, UMR CNRS 5224, Université Grenoble Alpes

Healthy cognitive aging manifests with a gradual decline in lexical production (LP) beginning in middle age. Previous research showed that LP decline is not solely attributed to domain-specific mechanisms (e.g., language) but also involves domain-general factors like executive functioning. Moreover, while disruptions in functional connectivity have been linked to age-related LP decline, the structural correlates remain unclear. Therefore, this study aims to investigate structural modifications in conjunction with cognitive scores to elucidate LP decline among middle-aged adults. We analyzed seven LP-related cognitive scores alongside diffusion MRI data from 155 healthy adults aged 45-60 from the CAMCAN cohort. Mrtrix3 was used for preprocessing diffusion MRI data and whole-brain tractography (SIFT2). Specifically, we quantified structural alteration using Track-Weighted Fractional Anisotropy (TW-FA), enabling a more sensitive analysis at crossing fiber locations. Finally, we employed machine learning (PLS) to jointly examine the multivariate links between TW-FA values and cognitive scores in middle-aged adults. Our findings indicate that the onset of LP decline occurs around age 56, with prominent structural alterations in the right frontotemporal and cerebellar white matter. Interestingly, enhanced integrity observed in the left temporal white matter, linked to semantic performances, demonstrates a potential mitigating effect on these deteriorations. Furthermore, our study reveals that this mitigation is more effective in middle-aged adults exhibiting high executive functioning. These results provide empirical support for the recently introduced LARA model (Lexical Access and Retrieval in Aging), suggesting that the age-related decline in LP may stem from poorer cognitive control over semantic representations.

Topic Area: LANGUAGE: Development & aging