Poster E7, Saturday, August 18, 3:00 – 4:45 pm, Room 2000AB

Neurobiological correlates of age-related auditory verbal working memory decline

Maxime Perron1, Isabelle Deschamps1, Julie Poulin1, Pascale Tremblay1;1Université Laval, Centre de recherche CERVO

Introduction: Normal aging is associated with a decline in auditory verbal working memory (avWM) [1], which has been associated with changes in the structure and function of different parts of the prefrontal cortex. Given the important role that avWM plays in communication, such deficits could lead to communication difficulties (e.g. processing speech in noise). However, the mechanisms through which brain aging affects avWM during language processing have not yet been fully elucidated. The objective of this study was to investigate, using surface-based morphometry, the relationship between brain aging and avWM. Method: 21 adults have been recruited to date (13 F, 52.4±17.4 years, range=21-71 years). The objective is 35. All participants completed a pure-tone audiometry, a speech perception task and a cognitive evaluation, including an evaluation of auditory attention and a test of avWM, the running span test [2], during which they had to recall the last 3 to 6 items digits from lists of different lengths. MRI data were acquired on a Philips 3.0T including a T1 sequence (1 mm3). Analysis: MRI data processing was done with Freesurfer 6. Following pre-processing, images were segmented and parcellated using the Destrieux 2009 parcellation [3]. To investigate avWM decline, first, a series of linear regression were run using SPSS v25, with accuracy as the dependent variable, and age and hearing (pure-tone average (PTA)) as the independent variables. Next, to establish whether the microstructure of the parietal and prefrontal cortex contributes to the age-related avWM decline, a series of moderation analysis were conducted, using the macro PROCESS v2.16.3 for SPSS, with age as the independent variable, accuracy as the dependent variable, and measures of gray matter (volume, thickness, surface) as the moderators. PTA was used as covariate. Results: Controlling for hearing, the results show that age is associated with lower accuracy in the avWM task at span 3 (β=-.006, t=-2.302, p=.034) and 4 (β=-.008, t=-2.311, p=.033). Moderation analysis revealed conditional effects of gray matter on the relationship between age and avWM in the left supramarginal gyrus (SMG) and the left triangular part of the inferior frontal gyrus (IFGt), two regions that have been involved in vWM. The Pick-a-point approach [4] was used to probe these effects. These analyses revealed that, for the SMG, the relationship between age and accuracy was significant only at the lowest level of gray matter volume (β=-.009, t=-2.154 p=.047) and surface area (β=-.009, t=-2.506, p=.023). For the IFGt, this relationship was significant only at the lowest value of gray matter volume (β=-.011, t=-2.363, p=.031). That is, for participants with cortical decline in these regions, age affected accuracy in the avWM task. Conclusion: These preliminary analyses reveal that the microstructure of the parietal and prefrontal cortices is associated with age-related changes in avWM ability. Additional analyses are underway to further examine the avWM, auditory attention and speech perception in aging. References: [1]Hedden T., et al. (2001). Psychology and Aging. [2]Pollack, I. et al. (1959). Journal of Experimental Psychology. [3]Destrieux, C. et al. (2009). Neuroimage. [4]Bauer & Curran. (2005). Multivariate Behavioral Research.

Topic Area: Phonology and Phonological Working Memory