The relationship between mobility dysfunction staging and global cognitive performance

Objectives: To assess the relationship and the directionality between mobility and cognitive performance. Method: A cross-sectional analysis of a racially/ethnically diverse sample of 327 community-dwelling adults (mean age = 68.9 ± 9.9 y; range, 40 to 100 y) categorized as having no mobility dysfunction, upper-extremity (UE) impairment, lower-extremity (LE) impairment, or mobility limitation (both UE and LE impairments), and compared by global cognition with multiple hierarchical linear regression adjusted for sociodemographic, health, and mood factors. A bootstrapping mediation analysis investigated the directionality of the mobility-cognition association. Results: LE (Est. = -2.95 ± 0.77, P = 0.001) but not UE impairment (Est. = - 1.43 ± 1.05, P = 0.175) was associated with a poorer global cognitive performance/impairment. The presence of mobility limitation had the strongest effect on cognition (Est. = -3.78 ± 1.09, P < 0.001) adjusting for sociodemographic factors, body composition, comorbidities, and mood. Mediation analysis indicated that the relationship between cognition and mobility likely operates in both directions. Discussion: The association between cognitive function and mobility follows a dose-response pattern in which the likelihood of poor global cognition increases with the progression of mobility dysfunction, with evidence that LE impairments may be better indicators of an impaired cognitive status than UE impairments. Using brief, valid tools to screen older patients for early signs of mobility dysfunction, especially when the LE is affected, is feasible, and may provide the first detectable stage of future cognitive impairment and provide actionable steps for interventions to improve performance, reduce burden, and prevent the development of physical disability and loss of independence.