Abstract
Taiwan is changing from an aging society to an aged society very rapidly. The prevention of falls hence becomes one of the most critical issues. There have been many studies focusing on the risk factors of falls, among which the gait patterns of older adults were highlighted. However, the use of foot-eye coordination during walking also plays an important role. As found by previous studies, older adults with high risks of falls often transferred their gaze away from the target earlier, which leads to decreased accuracy of foot positioning. If gaze transfer is not allowed until heel-strike on the target, the more accurate foot positioning may help reduce the risk of falls due to trips or loss of balance. Ten older adults ranging from 55 to 65 years old and ten young adults ranging from 22 to 24 years old will be recruited in this study. Each participant is required to wear the eye-tracking system and the electromagnetic tracking system, so as to collect the eye movement parameters and gait data. There are two targets placed along the pathway. The first target is placed on a fixed position, while the second one is placed either one-step, two-step, or three-step away from the first one. The participant needs to walk forward while stepping on the first target and then the second target respectively. Under condition 1, the participant is required to keep looking at the first target until heel-strike on it, whereas no instruction is given to the second target. Under condition 2, the participant has to follow the instruction of foot-eye coordination for both targets. By comparing the differences in positioning error and task completion time between the two conditions, it can help determine whether the strategy of visual guidance takes effect over time. However, eye gaze on the target the pathway should be as important as on the environment in order not to make collision with other objects. So the next step is to find out the best timing when visual guidance should be triggered and terminated. The ten elder adults mentioned earlier participated in this experiment again. There are three targets fixed placed the pathway, Under condition 1, the participant is required to look at each target during the heel-strike of leading foot until heel-strike of the trailing foot on it, Under condition 2, the participant is required to look at each target during the foot-flat of leading foot until heel-strike on it. Under condition 3, the participant is required to looking at each target during the toe off of trailing foot until heel-strike on it. In the first experiment, the results show that foot positioning error is greater both in condition 1 than in condition 2, and in elder than in younger adults. In other words, visual guidance can’t take effect over time. Reminder of this strategy would be hence required during walking. In the second experiment, the results show that the best timing of visual guidance is to be triggered at the foot-flat of leading foot. In the future, the findings may serve as a reference for clinical applications to improve the safety of older adults in the home environment.