Lower Carotid Artery Compliance and Greater Carotid beta-stiffness Index are Associated With Slower Processing Speed and Reduced Working Memory Performance in Older Healthy Adults

Introduction: Higher central elastic artery stiffness is associated with greater brain white matter hyperintensity volume and lower cognitive performance in older adults. However, it is unknown if higher central artery stiffness is related to regional decreases in brain white matter integrity (WMI) and reductions in working memory or processing speed. We hypothesized that greater large elastic artery stiffness would be associated with lower working memory and slower processing speed as well as lower regional WMI in older adults. Methods: In young (n=19; 23.8 ± 0.7 yrs) and older (n=22; 64.4 ± 4.2 yrs; range 60-71 yrs) healthy adults, aortic stiffness (carotid-femoral pulse wave velocity, cfPWV, via tonometry) and carotid artery compliance and β-stiffness index (carotid artery ultrasound and tonometry) were determined non-invasively. WMI was assessed by fractional anisotrophy (FA) (3T MRI) from diffusion tensor images. An N-Back task and letter and pattern comparison tests were performed as measures of wor...