Department of Physical Therapy, Tokyo Metropolitan Rehabilitation Hospital, Tokyo, Japan.
Department of Physical Therapy, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan.
PLoS One. 2023 Jan 26;18(1):e0281012. doi: 10.1371/journal.pone.0281012. eCollection 2023.
Neck muscle vibration (NMV) influences proprioceptive sensations and modulates standing postural orientation and spatial perception. However, the effects of NMV in healthy participants would vary based on the influence of stimulus duration and combination with trunk muscle vibration. Therefore, this study with a cross-over design clarified these effects. Twenty-four healthy participants (mean age, 25.7±3.7 years) were enrolled. To assess standing postural orientation, standing center-of-pressure (COP) measurements were recorded on a COP platform, starting with closed eyes and then with open eyes. The mean mediolateral (ML) and anteroposterior (AP) position [mm] of COP and other parameters were calculated. To assess spatial perception, subjective straight ahead (SSA) measurements were recorded, wherein participants were instructed to point and project the position of the manubrium of sternum on the touch panel using their right index finger with their eyes closed. Measurements were taken before and after four conditions: no vibration (control), left NMV for 30 s, left NMV for 10 min, and left NMV and left lumbar back vibration for 10 min. Vibratory stimulation was performed with the eyes closed at 80 Hz. The measurements under the four conditions were conducted with random cross-over and 5-min resting period between the conditions. COP and SSA values were subtracted before and after each condition for standardized variation and compared. NMV combined with trunk muscle vibration for 10 min resulted in significant deviations of the ML-COP toward the stimulation side and AP-COP toward the anterior side compared to the control condition with closed eyes. SSA showed no significant differences. These findings suggest that NMV-induced nervous system modulation would be amplified by proprioceptive sensory input to trunk muscles. Therefore, this method could provide a new option for clinical trials on postural orientation using NMV. SSA based on proprioceptive sensation may not be biased without visual illusions.
颈部肌肉振动（NMV）会影响本体感觉，并调节站立姿势的定向和空间感知。然而，在健康参与者中，NMV 的影响会因刺激持续时间和与躯干肌肉振动的组合而有所不同。因此，本项交叉设计研究旨在阐明这些影响。共有 24 名健康参与者（平均年龄，25.7±3.7 岁）参与了这项研究。为了评估站立姿势的定向，在 COP 平台上记录了站立时的中心压力（COP）测量值，起始时为闭眼，然后睁眼。计算了 COP 的平均横向（ML）和前后（AP）位置[mm]和其他参数。为了评估空间感知，记录了主观直线（SSA）测量值，参与者被要求在闭眼的情况下，用右食指在触摸面板上指出并投射胸骨柄的位置。在四种条件下进行了测量：无振动（对照）、左侧 NMV 持续 30s、左侧 NMV 持续 10min 和左侧 NMV 和左侧腰部背部振动持续 10min。振动刺激在 80Hz 下闭眼进行。在四种条件下进行测量，采用随机交叉设计，并在条件之间有 5 分钟的休息期。在每种条件前后进行 COP 和 SSA 值的减法，以进行标准化变化，并进行比较。与闭眼对照条件相比，10min 的 NMV 与躯干肌肉振动相结合会导致 ML-COP 向刺激侧和 AP-COP 向前侧的显著偏差。SSA 没有显示出显著差异。这些发现表明，NMV 诱导的神经系统调节会因躯干肌肉的本体感觉输入而放大。因此，这种方法可以为使用 NMV 进行姿势定向的临床试验提供新的选择。基于本体感觉的 SSA 可能不会因视觉错觉而产生偏差。
