Horlings C G C, Carpenter M G, Honegger F, Allum J H J
Department of ORL, University Hospital, Basel, Switzerland.
Ann N Y Acad Sci. 2009 May;1164:1-12. doi: 10.1111/j.1749-6632.2009.03872.x.
Movement strategies controlling quiet stance and rapid balance corrections may have common characteristics. We investigated this assumption for lower leg proprioceptive loss (PL), peripheral vestibular loss (VL), and healthy controls. Our underlying hypothesis was that changes in movement-strategy modulation following sensory loss would improve with prosthetic biofeedback. Quiet stance was measured under different sensory conditions and compared to corrections induced by multidirection support-surface tilts. Response synergies were assessed using electromyography recordings from several muscles. Biofeedback of trunk sway during gait and stance tasks used lower trunk rotations to drive head-band-mounted vibro-tactile and auditory actuators. Strategies of quiet stance were different for roll and pitch, depending on sensory conditions. Simultaneously acting strategies were observed for low- and high-frequency sway. PL induced strategies different from those of VL and controls. VL strategies were identical to those of controls but with greater amplitudes. Tilt perturbation movement strategies were similar to high-frequency strategies of quiet stance--multisegmental. VL induced increased trunk pitch and roll responses with hypermetric trunk muscle responses and hypometric knee responses but unchanged synergies. Increasing PL up the legs caused changed synergies. Biofeedback reduced stance body sway in VL and elderly subjects. In conclusion, several movement strategies underlie quiet stance with high-frequency strategies being common to those of perturbed stance. PL changes both movement strategies and synergies, whereas VL only causes pathological changes to the modulation depth. Thus, VL is more easily rectified using trunk sway positional biofeedback.
控制安静站立和快速平衡校正的运动策略可能具有共同特征。我们针对小腿本体感觉丧失（PL）、外周前庭丧失（VL）和健康对照者对这一假设进行了研究。我们的基本假设是，感觉丧失后运动策略调制的变化会随着假体生物反馈而改善。在不同感觉条件下测量安静站立情况，并与多方向支撑面倾斜引起的校正进行比较。使用来自几块肌肉的肌电图记录评估反应协同作用。在步态和站立任务期间，通过下躯干旋转驱动头戴式振动触觉和听觉致动器，对躯干摆动进行生物反馈。安静站立的策略在横滚和俯仰方面有所不同，这取决于感觉条件。在低频和高频摆动中观察到了同时起作用的策略。PL导致的策略与VL和对照组不同。VL的策略与对照组相同，但幅度更大。倾斜扰动运动策略类似于安静站立的高频策略——多节段的。VL导致躯干俯仰和横滚反应增加，躯干肌肉反应过强，膝盖反应不足，但协同作用不变。腿部PL增加会导致协同作用改变。生物反馈减少了VL患者和老年受试者的站立身体摆动。总之，安静站立有几种运动策略作为基础，高频策略与受扰动站立的策略相同。PL改变了运动策略和协同作用，而VL仅导致调制深度的病理变化。因此，使用躯干摆动位置生物反馈更容易纠正VL。
