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 (713 +/- 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. Copyright (C) 2013, Taiwan Society of Geriatric Emergency 82 Critical Care Medicine. Published by Elsevier Taiwan LLC. All rights reserved.