Faculty of Sciences, Department of Physical Education, Laboratory of Information, Vision and Action (LIVIA), São Paulo State University (UNESP), Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, Vargem Limpa, Bauru, São Paulo, 17033-360, Brazil.
Graduate Program in Movement Sciences, São Paulo State University - UNESP, Bauru, São Paulo, Brazil.
Exp Brain Res. 2022 Feb;240(2):395-406. doi: 10.1007/s00221-021-06256-9. Epub 2021 Nov 5.
This study examined changes in postural control and gaze performance of faller and non-faller older adults under conditions of visual tasks and optical flow manipulations. Fifteen older non-fallers (69.8 years, ± 3.2) and fifteen older fallers (71.1 years, ± 6.4) stood on a force platform inside a moving room wearing an eye tracker. Four tasks were performed: gaze fixation; predictable saccades; unpredictable saccades; and free-viewing. The stimuli appeared at a frequency of 1.1 Hz during conditions of predictable and unpredictable saccades. Sixteen trials were divided into two blocks. In the first block, the room remained stationary. In the second block, the room oscillated, without the participant's awareness, with a 0.6 cm amplitude and 0.2 Hz frequency. Results showed postural sway attenuation in older fallers during the saccadic tasks compared to gaze fixation and free-viewing tasks, in both stationary and moving room conditions. Both groups showed increased center of pressure (CoP) magnitude during the moving room condition and CoP displacements strongly coupled to the room's movement. The influence of the moving room on the postural sway was reduced during the saccadic tasks for both older groups. Older fallers exhibited higher variability compared to older non-fallers. Gaze behavior differences between groups were dependent on the goals of the visual tasks. Therefore, CoP displacements of older adults are reduced during saccadic tasks regardless of their falling history. However, postural and gaze performance of older fallers suggests increased deterioration of postural and oculomotor control which may be used as a predictor of fall risk.
本研究考察了在视觉任务和光流操作条件下，跌倒者和非跌倒者老年人的姿势控制和注视表现的变化。15 名老年非跌倒者（69.8 岁，±3.2）和 15 名老年跌倒者（71.1 岁，±6.4）在一个移动室内的力平台上佩戴眼动追踪器站立。进行了四项任务：注视固定；可预测的扫视；不可预测的扫视；和自由观看。在可预测和不可预测扫视的条件下，刺激以 1.1Hz 的频率出现。16 次试验分为两个块。在第一个块中，房间保持静止。在第二个块中，房间在参与者不知情的情况下以 0.6cm 的振幅和 0.2Hz 的频率摆动。结果表明，与注视固定和自由观看任务相比，在静止和移动房间条件下，老年跌倒者在扫视任务中姿势摆动衰减。在移动房间条件下，两组的中心压力（CoP）幅度均增加，并且 CoP 位移与房间的运动强烈耦合。对于两个老年组，移动房间对姿势摆动的影响在扫视任务期间降低。与老年非跌倒者相比，老年跌倒者表现出更高的变异性。组间注视行为的差异取决于视觉任务的目标。因此，无论其跌倒史如何，老年人大腿的 CoP 位移在扫视任务中都会减少。然而，老年跌倒者的姿势和注视表现表明，姿势和眼球运动控制的恶化增加，这可能被用作跌倒风险的预测指标。
