The effects of dual-tasking on temporal gait adaptation and de-adaptation to the split-belt treadmill in older adults

Abstract

It has been well established that with aging, walking becomes more challenging when dividing attention towards other tasks (i.e. dual-tasks) and when adapting walking to environmental demands. Although these gait-related features are believed to contribute to an increased risk of falling in older adults, little is known about the interplay between dual-tasking and gait adaptation. To investigate whether the rate and variability of temporal gait adaptation to a split-belt treadmill and ensuing aftereffects are altered by dual-tasking in healthy older adults. Split-belt walking was assessed in 28 healthy older adults (mean age 69 years) who were free of any ongoing medical conditions affecting gait. Participants adapted their walking pattern to a split-belt treadmill at a 2:1 speed ratio (10 min) followed by 3 min of de-adaptation (both belts at the same speed) to assess aftereffects. Half of the participants performed an intermittent dual-task (auditory cognitive task) during the adaptation period, whereas the other half completed the adaptation period as a single task. Double support symmetry magnitude and variability were used to compare group differences in rate of adaptation to the split-belt condition and retention of aftereffects during de-adaptation. During adaptation, the presence of a dual-task slowed the rate of adaptation to the split-belts and was characterized by greater variability in the dual-task group compared to the single-task group. During the first minute of de-adaptation, both groups similarly decreased their double support asymmetry towards baseline performance. Still, the dual-task group had a significant decrease in asymmetry during the end of de-adaptation and spent less steps within baseline performance during the entire de-adaptation period compared to the single-task group (35% vs 50%). Dual-tasking led to slower and more variable temporal gait adaptation to the split-belt treadmill and larger variability during de-adaptation. Our findings indicate that in older adults, gait adaptation is affected by a competing cognitive task and highlights the importance of being aware of the influence of dual-task on short-term learning when developing rehabilitation programs for cognitive-motor interference.