Ledin T, Hafström A, Fransson P A, Magnusson M
Department of Otorhinolaryngology, Head and Neck Surgery, Linköping University Hospital, Linköping, Sweden.
Acta Otolaryngol. 2003 Jun;123(5):594-9. doi: 10.1080/00016480310001835.
Several reports have shown that the direction of the postural responses induced by vestibular stimulation is affected by the positions of the neck and torso. The aim of this study was to investigate whether the postural responses to vibratory proprioceptive stimulation of the calf muscles are affected by the position of the head and thus by proprioceptive and vestibular information from the neck and head.
Ten normal subjects were exposed to vibratory proprioceptive stimulation of the calf muscles when the head was maintained in five different positions: in a neutral position facing forwards, with the head turned to the right or left sides or with the head tilted backwards or forwards. Body movements were evaluated by analyzing the anteroposterior and lateral torques induced towards the supporting surface.
The analysis showed that only the anteroposterior body sway was significantly affected by the position of the head. The anteroposterior postural responses were primarily increased during the tests with the head tilted backwards or forwards, whereas the postural responses were unaffected by head torsion towards the sides. The lateral responses were primarily affected by vision and not by the position of the head.
The findings suggest that the responses evoked by vibratory proprioceptive stimulation of the calf muscles may be affected by different mechanisms, either by purely proprioceptive information or by an interaction between proprioceptive and vestibular information. Moreover, the increasing difference between the test conditions over time suggests that fatigue of the neck muscles may be one of the factors affecting the responses induced by the perturbations.
多项报告表明，前庭刺激诱发的姿势反应方向受颈部和躯干位置的影响。本研究的目的是调查小腿肌肉振动本体感觉刺激引发的姿势反应是否受头部位置影响，进而受来自颈部和头部的本体感觉和前庭信息影响。
10名正常受试者在头部保持五个不同位置时接受小腿肌肉的振动本体感觉刺激：面向前方的中立位置、头部向右侧或左侧转动、头部向后或向前倾斜。通过分析朝向支撑面诱发的前后向和侧向扭矩来评估身体运动。
分析表明，只有前后向身体摆动受头部位置的显著影响。在头部向后或向前倾斜的测试过程中，前后向姿势反应主要增加，而姿势反应不受头部向两侧扭转的影响。侧向反应主要受视觉影响，而非头部位置的影响。
研究结果表明，小腿肌肉振动本体感觉刺激诱发的反应可能受不同机制影响，要么是纯粹的本体感觉信息，要么是本体感觉和前庭信息之间的相互作用。此外，随着时间推移测试条件之间差异的增加表明，颈部肌肉疲劳可能是影响扰动诱发反应的因素之一。
