Lackner J R, Rabin E, DiZio P
Ashton Graybiel Spatial Orientation Laboratory and Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
J Neurophysiol. 2000 Nov;84(5):2217-24. doi: 10.1152/jn.2000.84.5.2217.
Touch of the hand with a stationary surface at nonmechanically supportive force levels (<1 N) greatly attenuates postural sway during quiet stance. We predicted such haptic contact would also suppress the postural destabilization caused by vibrating the right peroneus brevis and longus muscles of subjects standing heel-to-toe with eyes closed. In experiment 1, ten subjects were tested under four conditions: no-vibration, no-touch; no-vibration, touch; vibration, no-touch; and vibration, touch. A hand-held physiotherapy vibrator (120 Hz) was applied approximately 5 cm above the malleolous to stimulate the peroneus longus and brevis tendons. Touch conditions involved contact of the right index finger with a laterally positioned surface (<1 N of force) at waist height. Vibration in the absence of finger contact greatly increased the mean sway amplitude of the center of pressure and of the head relative to the no-vibration, no-touch control condition (P < 0.001). The touch, no-vibration and touch-vibration conditions were not significantly different (P > 0.05) from each other and both had significantly less mean sway amplitude of head and of center of pressure than the other conditions (P < 0.01). In experiment 2, eight subjects stood heel-to-toe under touch and no-touch conditions involving 40-s duration trials of peroneus tendon vibration at different duty cycles: 1-, 2-, 3-, and 4-s ON and OFF periods. The vibrator was attached to the subject's leg and remotely activated. In the no-touch conditions, subjects showed periodic postural disruptions contingent on the duty cycle and mirror image rebounds with the offset of vibration. In the touch conditions, subjects were much less disrupted and showed compensations occurring within 500 ms of vibration onset and mirror image rebounds with vibration offset. Subjects were able to suppress almost completely the destabilizing influence of the vibration in the 3- and 4-s duty cycle trials. These experiments show that haptic contact of the hand with a stable surface can suppress abnormal proprioceptive and motor signals in leg muscles.
在非机械支撑力水平（<1牛）下，手部与固定表面接触能在安静站立时显著减弱姿势晃动。我们预测，这种触觉接触也会抑制因振动闭眼脚跟对脚尖站立的受试者右侧腓骨短肌和长肌而导致的姿势不稳定。在实验1中，对10名受试者在四种条件下进行了测试：无振动、无接触；无振动、有接触；有振动、无接触；有振动、有接触。使用手持式物理治疗振动器（120赫兹）在踝关节上方约5厘米处刺激腓骨长肌和短肌腱。有接触的条件包括右手食指在腰部高度与侧向放置表面接触（力<1牛）。与无振动、无接触的对照条件相比，在没有手指接触的情况下振动会大大增加压力中心和头部的平均晃动幅度（P<0.001）。有接触、无振动和有接触、有振动这两种条件之间无显著差异（P>0.05），且两者的头部和压力中心平均晃动幅度均显著小于其他条件（P<0.01）。在实验2中，8名受试者脚跟对脚尖站立，在有接触和无接触条件下，对腓骨肌腱进行不同占空比（开和关周期分别为1、2、3和4秒）的40秒时长振动试验。振动器附着在受试者腿部并远程激活。在无接触条件下，受试者表现出取决于占空比的周期性姿势干扰以及振动停止时的镜像反弹。在有接触条件下，受试者受干扰程度小得多，且在振动开始后500毫秒内出现补偿以及振动停止时的镜像反弹。在3秒和4秒占空比试验中，受试者能够几乎完全抑制振动的不稳定影响。这些实验表明，手部与稳定表面的触觉接触可以抑制腿部肌肉中异常的本体感觉和运动信号。
