Age-related Differences in the Influence of Cognitive Task Performance on Postural Control Under Unstable Balance Conditions

Background: Poor multitask performance is commonly used as an indicator of age-related changes in attentional capacity. An inability to allocate sufficient attention to postural control under multitask conditions is thought to be a contributing factor to the risk of falling in older adults. This study examined age-related differences in the influence of cognitive task performance on postural sway and muscle activity on unstable balance conditions. Methods: Thirty healthy younger adults (22.2 ± 1.5 years of age, 15 men and 15 women) and 27 healthy older adults (71.3 ± 3.4 years of age, 13 men and 14 women) participated in the study. Participants performed a reaction time task under three conditions during standing on a compliant foam surface: holding a glass full of sand (control task), holding a glass of water (dual-manual task), and performing a control task while simultaneously performing a verbal fluency task (dual-cognitive task). Results: Both younger and older adults had a longer reaction time for the dual-cognitive task compared to the other two tasks (p < 0.01). Older participants exhibited decreased lower limb muscle activity and increased anterior–posterior trunk acceleration during the dual-cognitive task, while these effects were not observed in younger adults. Conclusion: Increasing attentional demand by implementing a cognitive task concomitant with a balance task had a greater influence on postural control in older compared to younger adults