Effects of age, sex, frailty and falls on cognitive and motor performance during dual-task walking in older adults

Background: Dual-task (DT) walking is of great interest in clinical evaluation to evaluate the risk of falling or cognitive declines in older adults. However, it appears necessary to investigate deeply the confounding factors to better understand their impact on dual-task performance.Objective: To evaluate the effect of age, sex, falls and frailty on cognitive and motor parameters in dual-task walking.Subjects: 66 older participants (mean age = 75.5 +/- 6.3; mean height = 165.8 +/- 8.4 cm; mean weight = 68.4 +/- 14 kgs) were split into groups based on their age, sex, fall and frailty status.Methods: Participants performed single-task walking, single-task cognitive (serial subtraction of 3), and dual-task walking (subtraction + walking) for 1 min at their fast pace. Gait speed, step length, step length variability, stance and swing phase time, single and double support, cadence, step time variability and gait speed variability were recorded in single-and dual-task walking and used to calculate the dual-task effect (DTE) as ((DT -ST) / ST) * 100). The cognitive score (DTEcog) was calculated as the number of correct responses minus errors. Generalized linear mixed models (GLMM) were used to compare the effects of falls, frailty, age and sex on gait and cognitive variables.Results: The interaction frailty*sex and frailty*age were the major effect on the DTEs. Specifically, the DTE was higher in women than men and in the frail group compared to non-frail.Conclusions: The present findings provide a better understanding on the confounding factors explaining the behavior in DT that could be used to develop more effective dual-task clinical programs for community-living older adults.