Successful adaptation of gait in healthy older adults during dual-task treadmill walking

ABSTRACT

Dual-task methods have been used to demonstrate increased prioritization of walking performance over cognition in healthy aging. This is expressed as greater dual-task costs in cognitive performance than in walking. However, other research shows that older adults can prioritize cognitive performance over walking when instructed to do so. We asked whether age-related cognitive prioritization would emerge by experimentally manipulating cognitive difficulty. Young and older adults performed mental arithmetic at two levels of difficulty, alone or while walking. Electromyography and footswitches were used to measure muscle activity and stride parameters. Under high cognitive load, older adults increased their stride time, stride length, and hamstring activity, while maintaining their cognitive performance. Young adults showed negligible dual-task costs in each domain. The older adults appeared to successfully adapt their stride in response to high cognitive demands. The results have implications for neural models of gait regulation, and age differences in task emphasis.

Keywords:

• Dual-task
• Gait
• EMG
• Cognition
• Healthy aging

Acknowledgments

This research was supported by graduate scholarship funding awarded to GA from the Centre for Research in Human Development (CRDH), a PGS-2 scholarship awarded to SAF from the Natural Sciences and Engineering Research Council (NSERC), and an NSERC Discovery Grant (238627) awarded to KZHL. We sincerely thank Claudia Starnino and Anthony Hopley for their help with participant recruitment and data collection, and Virginia Penhune for comments on the manuscript.