The aim of this study was to investigate body sway in 3 axial directions while walking under multitask conditions to assess the effects of task type and aging associated with the risk of falling. Body sway was measured with a single 3-axis acceleration sensor attached to the hip. Ten healthy young and 11 elderly individuals participated the experiment. The task conditions were 1) normal walking, walking with the following additional tasks: 2) a visual task, 3) an auditory task, 4) a calculation task, 5) visual and calculation tasks, and 6) auditory and calculation tasks. Significant differences in left-right direction body sway in condition 5 and forward-backward direction body sway in condition 3 were observed between elderly and young people. These results imply that, compared to young people, postural control in elderly individuals is more visually dependent and route changes based on sound prompts lead to excessive attentional load in elderly individuals.
Aim: This study compared changes in autonomic nerve indicators of high frequency (HF) norm and low frequency (LF)/HF ratio among young and elderly participants before and after standing: when actively standing up, when passively standing up with assistance from others, and when standing up with the aid of a lower-limb power-assisted robot (HAL) from a sitting position on a 40 cm-high chair. Methods: The sample comprised 11 healthy young and 14 elderly individuals aged 20-26 years (mean: 22.5±2.2) and 66-77 years (mean: 70.3±3.5), participants were asked to stand up under 3 different conditions and electrocardiogram measurements and blood pressure were measured. Results and Conclusion: Young and elderly participants showed decreased RRI across all conditions and no significant differences in average blood pressure were found before or after standing. Decreased HF norm and increased LF/HF ratio showed excitation of the sympathetic nerves, increasing blood pressure to compensate for and prevent orthostatic hypotension. Such compensation was likely not due to age although significant differences were found in the coefficient variance of RRI between young and elderly participants. HAL standing proved to have a marginal impact on young and elderly persons’ circulatory dynamics.