Patel M, Fransson P A, Lush D, Gomez S
Department of Otorhinolaryngology Head and Neck Surgery, Clinical Sciences, Lund University Hospital, Lund, Sweden.
Gait Posture. 2008 Nov;28(4):649-56. doi: 10.1016/j.gaitpost.2008.04.018. Epub 2008 Jul 7.
A common assessment of postural control often involves subjects standing on a compliant surface, such as a foam block, to make balance tests more challenging. However, the physical properties of the foam block used by different researchers can vary considerably. The objective of this study was to provide an initial approach for investigating whether two of the foam properties, i.e. density and elastic modulus, influenced recorded anteroposterior and lateral torque variance with eyes open and eyes closed. Thirty healthy adults (mean age 22.5 years) were assessed with posturography using three different types of foam block placed on a force platform. These blocks were categorised: firm foam, medium foam and soft foam by their elastic modulus. To investigate the spectral characteristics of recorded body movements, variance values were calculated for total movements, movements <0.1Hz and movements >0.1Hz. Results showed that anteroposterior and lateral torque variances >0.1Hz were larger when standing on the firm foam compared with medium and soft foam and in turn were larger on the medium foam compared with the soft foam with eyes closed. Moreover, GLM and correlation analysis demonstrated that the properties of the foam blocks affected anteroposterior torque variance >0.1Hz and lateral torque variance in all frequency ranges. In addition, the stabilising effect of vision in the anteroposterior direction had a greater influence when the subjects' stability was increasingly challenged by the support surface, as illustrated by the higher torque variance values. In conclusion, caution should be taken when analysing balance deficits with foam test setups, because the foam properties may influence the recorded body movements.
对姿势控制的常见评估通常包括让受试者站在诸如泡沫块之类的顺应性表面上，以使平衡测试更具挑战性。然而，不同研究人员使用的泡沫块的物理特性可能有很大差异。本研究的目的是提供一种初步方法，以调查泡沫的两个特性，即密度和弹性模量，是否会影响睁眼和闭眼时记录的前后向和侧向扭矩变化。使用放置在测力平台上的三种不同类型的泡沫块，对30名健康成年人（平均年龄22.5岁）进行姿势描记法评估。这些泡沫块根据其弹性模量分为：硬泡沫、中泡沫和软泡沫。为了研究记录的身体运动的频谱特征，计算了总运动、<0.1Hz的运动和>0.1Hz的运动的变化值。结果表明，与中泡沫和软泡沫相比，站在硬泡沫上时，睁眼和闭眼情况下>0.1Hz的前后向和侧向扭矩变化更大，而与软泡沫相比，站在中泡沫上时这些变化又更大。此外，广义线性模型和相关性分析表明，泡沫块的特性会影响所有频率范围内>0.1Hz的前后向扭矩变化和侧向扭矩变化。此外，正如较高的扭矩变化值所示，当支撑面给受试者的稳定性带来越来越大的挑战时，视觉在前后方向上的稳定作用影响更大。总之，在使用泡沫测试装置分析平衡缺陷时应谨慎，因为泡沫特性可能会影响记录的身体运动。
