Fujii Manami, Chirumbole Sophia G, Wagner Andrew R, Caccese Jaclyn B, Chaudhari Ajit M W, Wang Wei, Lu Bo, Merfeld Daniel M
Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, United States.
Biomedical Engineering, The Ohio State University, Columbus, OH, United States.
Front Neurol. 2025 Aug 25;16:1638493. doi: 10.3389/fneur.2025.1638493. eCollection 2025.
External continuous perturbations using a motion platform have been developed by employing either sum-of-sines (SoS) or a pseudorandom ternary sequence (PRTS) of numbers to quantify body sway evoked in the medial-lateral (ML) or anterior-posterior (AP) directions, which ultimately helps understand the human postural control system. These stimuli have been provided via pitch tilts of the motion platform for evaluations of AP balance responses or roll tilts for ML balance responses. However, little is known about whether a healthy postural control system responds to 2-dimensional (2D) perturbations similarly when the perturbation stimuli are provided in semicircular canal coordinates (i.e., right-anterior/left-posterior (RALP) and left-anterior/right-posterior (LARP)) versus roll/pitch coordinates. Stimuli provided in either set of coordinates were orthogonal in both time and space. Our 2D platform perturbations provided in RALP/LARP coordinates will have the potential to better assess the contribution of each pair of the vertical semicircular canals to postural control for individuals with dysfunction of the vertical semicircular canals.
To address this knowledge gap, we developed four different balance perturbation trajectories using sum-of-sines (SoS) signals and simultaneously provided those stimuli in (i) roll and pitch, (ii) RALP and LARP, and (iii) roll, pitch, RALP, and LARP dimensions. Center of pressure (CoP) data were collected from 24 healthy participants (40 13 years of age) on a commercially available motion platform (Virtualis Motion VR, Perault, France). A discrete Fourier transform (DFT) was applied to the CoP data to identify responses at perturbed frequencies (i.e., spectral response components).
We found that ML and AP postural responses were not significantly different when the platform perturbations were simultaneously provided in RALP/LARP coordinates versus roll/pitch coordinates.
This finding suggests that our 2D platform perturbations in RALP/LARP coordinates allow us (1) to compare ML and AP responses evoked by RALP and LARP stimuli to existing literature showing those responses evoked by roll and pitch stimuli and (2) to characterize postural responses for individuals with sensory deficits to better isolate contributions of the vertical semicircular canals to postural control.
利用运动平台施加外部连续扰动，通过采用正弦和（SoS）或伪随机三元序列（PRTS）来量化在内外侧（ML）或前后方向（AP）诱发的身体摆动，这最终有助于理解人体姿势控制系统。这些刺激通过运动平台的俯仰倾斜来评估AP平衡反应，或通过横滚倾斜来评估ML平衡反应。然而，当在半规管坐标（即右前/左后（RALP）和左前/右后（LARP））与横滚/俯仰坐标中提供扰动刺激时，健康的姿势控制系统是否以类似方式对二维（2D）扰动做出反应，目前所知甚少。在任何一组坐标中提供的刺激在时间和空间上都是正交的。我们在RALP/LARP坐标中提供的2D平台扰动将有可能更好地评估每对垂直半规管对垂直半规管功能障碍个体姿势控制的贡献。
为了填补这一知识空白，我们使用正弦和（SoS）信号开发了四种不同的平衡扰动轨迹，并同时在（i）横滚和俯仰、（ii）RALP和LARP以及（iii）横滚、俯仰、RALP和LARP维度中提供这些刺激。从24名健康参与者（年龄40±13岁）在商用运动平台（Virtualis Motion VR，法国佩罗）上收集压力中心（CoP）数据。对CoP数据应用离散傅里叶变换（DFT）以识别在扰动频率下的反应（即频谱反应成分）。
我们发现，当在RALP/LARP坐标与横滚/俯仰坐标中同时提供平台扰动时，ML和AP姿势反应没有显著差异。
这一发现表明，我们在RALP/LARP坐标中的2D平台扰动使我们能够（1）将RALP和LARP刺激诱发的ML和AP反应与现有文献中显示的横滚和俯仰刺激诱发的那些反应进行比较，以及（2）表征感觉缺陷个体的姿势反应，以更好地分离垂直半规管对姿势控制的贡献。
