The association between mobility and a cognitive measure of attention and processing speed in middle-aged adults: a cross-sectional study.

Mobility and cognitive functions are closely linked in old age. Although a relationship between mobility and cognitive function has also been demonstrated in midlife, it has not been tested under conditions that might reflect real-life locomotion. In this study, the association between attention and processing speed, as measured by choice reaction time (CRT), and mobility in midlife was examined using spatiotemporal gait indices during outdoor walking and a self-perceived mobility questionnaire. Fifty middle-aged adults (53.98 ± 5.32 years) completed a 2-minute walk in an urban environment with and without a dual task of texting on a smartphone. Gait speed, gait variability (stride time variability), and gait similarity (dynamic time warping) in the anteroposterior and medio-lateral axes were measured, and self-perceived mobility was assessed using the Mobility in Middle Age Questionnaire (MMQ). Attention and processing speed were measured with the Deary-Liewald CRT. Slower CRT was associated with reduced medio-lateral similarity during dual-task walking (r = 0.316, p = 0.032) and with lower self-perceived mobility (MMQ, r = -0.422, p = 0.007). Hierarchical regression analysis showed that medio-lateral gait similarity explained 10.0% of the variance in CRT, while self-perceived mobility explained 14.4%. The relationship between mobility and cognition in ecologically valid contexts may indicate a common age-related mechanism that emerges in midlife and can be exploited by interventions and monitoring programs aimed at promoting healthy aging.