ABSTRACT NUMBER: ESOC2026A1981 STRUCTURAL DETERMINANTS OF DECISION-MAKING IN PATIENTS WITH CEREBRAL SMALL VESSEL DISEASE

Abstract Background and aims Decision-making is a crucial cognitive process required in daily life and relies on a cortical network, including dorsolateral prefrontal, posterior parietal and motor regions. The structural determinants of this network remain poorly understood. We aimed to investigate decision-making in patients with cerebral small vessel disease (CSVD) to explore the impact of disrupted white matter integrity on decision-making. Methods Perceptual decision-making was investigated using the Random Dot Motion (RDM) task. Task performance was analyzed using computational modelling based on the Drift Diffusion Model (DDM). All participants underwent brain MRI, and markers of neurodegeneration (brain volume, cortical thickness) and vascular brain damage (white matter hyperintensities [WMH], peak width of skeletonized mean diffusivity [PSMD]) were quantified. Age- and sex-adjusted regression analyses were performed to examine associations between structural brain alterations and decision-making. Results We included 52 participants (mean age 66 years, 44% male). Vascular risk factors were common: 39% had arterial hypertension and 29% hypercholesterolemia. In the RDM task, mean reaction time was 1.63 seconds and mean accuracy was 0.78. Structural MRI showed a mean cortical thickness of 2.37 mm, a mean PSMD of 0.00015 and mean WMH volume was 7.7 ml, corresponding to a mean WMH load of 0.54%. Analyses examining associations between structural brain alterations and decision-making parameters will be presented at ESOC. Conclusions By combining computational modelling with multimodal imaging, this study provides a framework to investigate how vascular brain damage and network integrity influence perceptual decision-making. These findings may contribute to a better understanding of mechanisms underlying cognitive dysfunction in CSVD. Conflict of interest Janine Hügle: nothing to disclose, Götz Thomalla:received consultancy fees from Acandis, Boehringer Ingelheim, Bayer, and Portola, and fees as lecturer from Acandis, Alexion, Amarin, Bayer, Boehringer-Ingelheim, BMS/Pfizer, Daiichii Sankyo and Portola. He serves in the board of the TEA Stroke Study and of ESO, Märit Jensen: nothing to disclose, Marvin Petersen: nothing to disclose, Peter Murphy: nothing to disclose, Eckhard Schlemm: nothing to disclose, Bastian Cheng: nothing to disclose, Tobias Donner: nothing to disclose.