Neurovascular de-coupling underlies dual-task cost across cognitive abilities.

INTRODUCTION: We tested the hypothesis that increased middle cerebral artery velocity (MCA velocity) during complex motor (overground walking) and cognitive tasks (e.g., dual task) is associated with cognitive performance in older adults with varying levels of cognitive ability. METHODS: Fifty-six participants (19 females, 75 ± 7 years old) completed a seated single task that assessed working memory performance; a walking single task, assessing overground walking gait speed; and a dual task, combining both. Continuous MCA velocity was collected, and participants completed a Montreal Cognitive Assessment (MoCA). RESULTS: Higher MCA velocity was associated with faster gait speed, better working memory performance, and greater MoCA scores (all p < 0.05). Participants with lower MoCA scores had lower MCA velocity (p = 0.052), slower gait speed (p = 0.035), and lower working memory performance (p = 0.016) than people with higher MoCA scores. The hyperemic response of MCA velocity from single task walking to the dual task with increased cognitive load significantly contributed to MoCA scores (p = 0.017). DISCUSSION: The functional response of cerebral blood flow with these tests suggests vascular properties may be considered a biomarker indicative of subclinical cognitive function during walking tasks. Highlights: Mobile devices simultaneously assessed neurovascular coupling and dual-task cost.Middle cerebral artery velocity (MCA velocity) is negatively associated with dual-task cost.MCA velocity is associated with gait speed, working memory, and Montreal Cognitive Assessment scores.MCA velocity decreased from controls to mild cognitive impairment to dementia.Novel methodological approach to utilize MCA velocity during overground walking, single-tasks, and dual-tasks.