Dual-Task Step Initiation Time Predicts 10-17 Year Mortality Risk in Older Adults

Researchers at Ben-Gurion University measured single-task and dual-task voluntary step execution plus static postural sway in participants aged 65 and older, then linked results to national survival records. The dual-task condition paired a rapid forward step to a somatosensory cue with a modified Stroop color-naming task. Step initiation latency, not foot-off time or sway velocity, emerged as the strongest independent predictor after age adjustment. Kaplan-Meier curves stratified by quartiles showed clear separation persisting beyond age 75. This extends prior gait-speed literature by isolating central processing delay rather than gait speed itself. Related work in JAMA 2011 and Lancet 2019 established usual gait speed as a mortality biomarker, yet those studies used steady-state walking without cognitive load. The present design highlights attentional competition as a distinct frailty signal. Static balance measures retained modest predictive value but were inferior once dual-task latency entered multivariable models. The 28 percent hazard increment per 100 ms therefore captures integrated neuromuscular and executive-function reserve not fully indexed by single-task tests.