Zusammenfassung

Many adults have difficulty doing two things at once, especially walking and completing another motor task. In older adults, this could lead to a fall. Further, falls during walking have been associated with changes in gait variability or the natural stride-to-stride fluctuations while walking. The aging process contributes to a more variable gait cycle, which contributes to falls, and has been used to predict falls occurrence. This project investigated the effect of task difficulty during dual-motor tasking on gait variability in young and older healthy adults. Fifteen young adults (20.6 ± 2 years, 167.4 ± 6.5 cm, 65.0 ± 5 kg), and five older adults (72 ± 3 years, 169.2 ± 13.3 cm, 68.7 ± 10.9 kg) completed of a series of dual-task conditions, 3½ minutes each, where the opaqueness of the tray and/or the amount of water in glasses on top of the tray (task difficulty) varied while walking on a self-paced treadmill. For each condition: sample entropy was calculated on step length, step time and step width. Older adults showed significantly less repetitive step length values than young adults (p=0.04). Step length was less repetitive during baseline walking as compared to conditions in which vision or task difficulty was altered (p’s=0.005, 0.021, 0.006, <.001 respectively). Larger sample size may help increase the significant differences between groups: trends suggest that a secondary motor task impacts step length in both populations. Older adults were impacted to a greater extent suggesting a more variable, less repetitive gait, consistent with previous literature in prediction of falls.