Department of Health and Rehabilitation Sciences, Temple University, Pearson Hall, 1800 N Broad St, 19121, Philadelphia, PA, USA.
Department of Psychology and Neuroscience, Temple University, Weiss Hall, 1701 North 13th St, 19122, Philadelphia, PA, USA.
J Neuroeng Rehabil. 2022 Jul 26;19(1):81. doi: 10.1186/s12984-022-01059-7.
The ability to maintain upright posture requires successful integration of multiple sensory inputs (visual, vestibular, and somatosensory). When one or more sensory systems become unreliable, the postural control system must "down-weight" (or reduce the influence of) those senses and rely on other senses to maintain postural stability. As individuals age, their ability to successfully reweight sensory inputs diminishes, leading to increased fall risk. The present study investigates whether manipulating attentional focus can improve the ability to prioritize different sensory inputs for postural control.
Forty-two healthy adults stood on a balance board while wearing a virtual reality (VR) head-mounted display. The VR environment created a multisensory conflict amongst the different sensory signals as participants were tasked with maintaining postural stability on the balance board. Postural sway and scalp electroencephalography (EEG) were measured to assess visual weighting and cortical activity changes. Participants were randomized into groups that received different instructions on where to focus their attention during the balance task.
Following the instructions to direct attention toward the movement of the board (external focus group) was associated with lower visual weighting and better balance performance than when not given any instructions on attentional focus (control group). Following the instructions to direct attention towards movement of the feet (internal focus group) did not lead to any changes in visual weighting or balance performance. Both external and internal focus groups exhibited increased EEG alpha power (8-13 Hz) activity over the occipital cortex as compared to the control group.
Current results suggest that directing one's attention externally, away from one's body, may optimize sensory integration for postural control when visual inputs are incongruent with somatosensory and vestibular inputs. Current findings may be helpful for clinicians and researchers in developing strategies to improve sensorimotor mechanisms for balance.
维持直立姿势需要成功整合多种感觉输入（视觉、前庭和躯体感觉）。当一个或多个感觉系统变得不可靠时，姿势控制系统必须“减轻”（或减少）这些感觉的影响，并依靠其他感觉来维持姿势稳定性。随着个体年龄的增长，他们成功重新加权感觉输入的能力下降，导致跌倒风险增加。本研究旨在探讨注意力集中是否可以改善优先考虑不同感觉输入以进行姿势控制的能力。
42 名健康成年人在平衡板上站立，同时佩戴虚拟现实（VR）头戴式显示器。VR 环境在不同感觉信号之间产生了多感觉冲突，参与者的任务是在平衡板上保持姿势稳定。测量姿势摆动和头皮脑电图（EEG）以评估视觉权重和皮质活动变化。参与者被随机分配到在平衡任务中接受不同注意力集中指导的组。
按照指示将注意力集中在板的运动上（外部焦点组）与未给予注意力集中指导（对照组）相比，视觉权重较低，平衡表现更好。按照将注意力集中在脚部运动上的指示（内部焦点组）并没有导致视觉权重或平衡表现的任何变化。与对照组相比，外部和内部焦点组的枕叶皮质的脑电图α 功率（8-13 Hz）活动均增加。
目前的结果表明，将注意力集中在身体外部，远离身体，可能会优化视觉输入与躯体感觉和前庭感觉输入不一致时的姿势控制感觉整合。目前的研究结果可能有助于临床医生和研究人员制定改善平衡的感觉运动机制的策略。
