Li Ruixuan, Walter Hannah, Curry Christopher, Rath Ruth, Peterson Nicolette, Stoffregen Thomas A
University of Minnesota, Minneapolis, USA.
Exp Brain Res. 2018 Jun;236(6):1631-1641. doi: 10.1007/s00221-018-5246-y. Epub 2018 Mar 27.
The postural instability theory of motion sickness predicts that subjective symptoms of motion sickness will be preceded by unstable control of posture. In previous studies, this prediction has been confirmed with measures of the spatial magnitude and the temporal dynamics of postural activity. In the present study, we examine whether precursors of visually induced motion sickness might exist in postural time-to-contact, a measure of postural activity that is related to the risk of falling. Standing participants were exposed to oscillating visual motion stimuli in a standard laboratory protocol. Both before and during exposure to visual motion stimuli, we monitored the kinematics of the body's center of pressure. We predicted that postural activity would differ between participants who reported motion sickness and those who did not, and that these differences would exist before participants experienced subjective symptoms of motion sickness. During exposure to visual motion stimuli, the multifractality of sway differed between the Well and Sick groups. Postural time-to-contact differed between the Well and Sick groups during exposure to visual motion stimuli, but also before exposure to any motion stimuli. The results provide a qualitatively new type of support for the postural instability theory of motion sickness.
晕动病的姿势不稳定理论预测，晕动病的主观症状会先于姿势的不稳定控制出现。在先前的研究中，这一预测已通过姿势活动的空间幅度和时间动态测量得到证实。在本研究中，我们检验了视觉诱发晕动病的先兆是否可能存在于姿势接触时间中，姿势接触时间是一种与跌倒风险相关的姿势活动测量指标。站立的参与者按照标准实验室方案暴露于振荡视觉运动刺激中。在暴露于视觉运动刺激之前和期间，我们监测了身体压力中心的运动学。我们预测，报告有晕动病的参与者和没有晕动病的参与者之间的姿势活动会有所不同，并且这些差异会在参与者出现晕动病主观症状之前就存在。在暴露于视觉运动刺激期间，健康组和患病组的摇摆多重分形性有所不同。在暴露于视觉运动刺激期间，健康组和患病组的姿势接触时间不同，但在暴露于任何运动刺激之前也不同。这些结果为晕动病的姿势不稳定理论提供了一种全新性质的支持。
