Vestibular influences on human postural control in combinations of pitch and roll planes reveal differences in spatiotemporal processing
Vestibular influences on human postural control in combinations of pitch and roll planes reveal differences in spatiotemporal processing
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DOI：
10.1007/s002210100802
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发表时间：
2001-09-01
影响因子：
2
通讯作者：
Honegger, F
中科院分区：
文献类型：
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作者：
Carpenter, MG;Allum, JHJ;Honegger, F
本研究考察了人类双侧外周前庭缺失(BVL)对俯仰面和滚动面多方向表面旋转的姿势反应的影响。具体地说，我们研究了前庭丧失对腿部和躯干肌肉早期伸展、平衡纠正和稳定反应的方向敏感性、时机和幅度的影响，以及支撑面多方向旋转扰动后踝关节扭矩和躯干角速度的变化。14名正常健康成人和5名BVL患者站在以50度旋转7.5度的双轴转台上/S，通过相隔45度的8个不同方向的俯仰和侧滚组合。在一系列44个干扰试验中，方向被随机分配，这些试验首先是睁着眼睛，然后是第二个闭着眼睛的系列试验。前庭缺失不影响平衡矫正反应(120-220ms)的激活范围或最大敏感度方向。胫前肌(TA)、比目鱼肌(SOL)、棘旁肌(PARAS)或股四头肌在大约120ms时的反应起点是正常的。在BVL患者中，只有SOL肌肉活动在向前(脚趾向下)和滚动扰动的组合中显示出38-45ms的延迟。除1例外，BVL患者在睁眼和闭眼状态下，腿部肌肉在120~220ms之间的平衡矫正反应的波幅均显著降低。对于脚趾向上和脚趾向下的扰动，SOL反应在两侧都减少了，但在下坡(承重)腿中，对于联合的侧滚和俯仰扰动，SOL反应更显著地减少。对于脚趾向上的扰动，在两侧的TA显著减少，而对于向后翻滚的扰动，在下坡腿的TA显著减少。然而，正向扰动在120至220ms之间在BVL中引起明显更大的TA活动，这将进一步破坏身体的稳定。由于反应幅度的这些变化，与正常人相比，BVL患者的平衡矫正踝关节扭矩在160至260 ms之间减少，而扭矩在280至380 ms之间增加。BVL和正常的踝关节扭矩向量在方向上没有差异，两者都主要沿着螺距平面定位。对于向后(脚趾向上)和侧滚扰动的组合，BVL患者在Paras中有更大的平衡校正和稳定反应(350-700ms)，这与躯干俯仰和侧滚速度过快相对应。在侧滚扰动期间，BVL受试者在200ms后的主干速度方向与正常人不同。此外，横摇不稳定出现的时间要晚于俯仰，特别是在后向横摇扰动下。研究结果表明，滚动面和俯仰面旋转的组合产生了重要的时空信息，特别是关于BVL改变的主干响应策略，而这些策略不能仅由俯仰面扰动来揭示。我们的结果表明，前庭对俯仰平面的影响较早，并针对腿部肌肉，而侧滚控制较晚，集中在躯干肌肉。
The present study examined the influence of bilateral peripheral vestibular loss (BVL) in humans on postural responses to multidirectional surface rotations in the pitch and roll planes. Specifically, we examined the effects of vestibular loss on the directional sensitivity, timing, and amplitude of early stretch, balance correcting, and stabilizing reactions in postural leg and trunk muscles as well as changes in ankle torque and trunk angular velocity following multidirectional rotational perturbations of the support surface. Fourteen normal healthy adults and five BVL patients stood on a dual axis rotating platform which rotated 7.5 degrees at 50 degrees /s through eight different directions of pitch and roll combinations separated by 45 degrees. Directions were randomized within a series of 44 perturbation trials which were presented first with eyes open, followed by a second series of trials with eyes closed. Vestibular loss did not influence the range of activation or direction of maximum sensitivity for balance correcting responses (120-220 ms). Response onsets at approximately 120 ms were normal in tibialis anterior (TA), soleus (SOL), paraspinals (PARAS), or quadriceps muscles. Only SOL muscle activity demonstrated a 38- to 45-ms delay for combinations of forward (toe-down) and roll perturbations in BVL patients. The amplitude of balance correcting responses in leg muscles between 120 and 220 ms was, with one exception, severely reduced in BVL patients for eyes open and eyes closed conditions. SOL responses were decreased bilaterally for toe-up and toe-down perturbations, but more significantly reduced in the downhill (load-bearing) leg for combined roll and pitch perturbations. TA was significantly reduced bilaterally for toe-up perturbations, and in the downhill leg for backward roll perturbations. Forward perturbations, however, elicited significantly larger TA activity in BVL between 120 and 220 ms compared to normals, which would act to further destabilize the body. As a result of these changes in response amplitudes, BVL patients had reduced balance correcting ankle torque between 160 and 260 ms and increased torque between 280 and 380 ms compared to normals. There were no differences in the orientation of the resultant ankle torque vectors between BVL and normals, both of which were oriented primarily along the pitch plane. For combinations of backward (toe-up) and roll perturbations BVL patients had larger balance correcting and stabilizing reactions (between 350 and 700 ms) in PARAS than normals and these corresponded to excessive trunk pitch and roll velocities. During roll perturbations, trunk velocities in BVL subjects after 200 ms were directed along directions different from those of normals. Furthermore, roll instabilities appeared later than those of pitch particularly for backward roll perturbations. The results of the study show that combinations of roll and pitch surface rotations yield important spatiotemporal information, especially with respect to trunk response strategies changed by BVL which are not revealed by pitch plane perturbations alone. Our results indicate that vestibular influences are earlier for the pitch plane and are directed to leg muscles, whereas roll control is later and focused on trunk muscles.