REGULATORY MECHANISMS SUBSERVING POSTURAL STABILITY

拟议研究的目的是检查关系 多余的感觉信号和不同的生物力学 影响姿势稳定性的安排。 是分段的 以全球方式预先规划的恢复稳定行动， 身体的质量中心在支持的基础上，或者他们不断地 计算出与感官输入的局部变化相匹配的结果吗身体变化 机制、局部感觉输入和/或即将发生的事件的预测， 被认为是正常日常生活中姿势控制的重要组成部分 活动 阐明这些机制中的每一种如何影响 对姿势不稳定的反应应有助于临床医生评估 跌倒和平衡紊乱的原因。 这种澄清将 改善干预措施，训练患者进行补偿 或适应姿势紊乱。 为了实现这一目标，双方 将测试正常受试者和双侧睾丸切除患者。 受试者将在俯仰平面内以各种方式旋转和平移 姿势状态（例如，坐着，站着）与旋转轴 无论是在头部、质心还是脚踝。 受试者还将 当以某种姿势站立时，头部和/或躯干固定不动 平台，可以伺服到脚踝的角度。 这将允许 选择性消除前庭、颈部和踝部本体感受 输入，以测量每个感官信号对 反应 将要求受试者自愿稳定， 干扰力，或者用心算来分散自己的注意力。 将使用两种刺激波形。离散的、可预测的斜坡波 将提供有关相关的延迟和幅度的信息， 应答 伪随机斜坡将唤起更多的自动特征 的反应。 与总体目标有关的具体问题包括 确定调节空间的机械参数的研究 和时间序列的稳定反应，检查的影响， 预测肌肉激活的模式，并确定线性 感觉信号和功能稳定性之间的关系。

The purpose of the proposed studies is to examine the relations between the redundant sensory signals and varying biomechanical arrangements that influence postural stability. Are the segmental restabilizing actions preprogrammed in a global fashion to maintain the body's center of mass over the base of support, or are they continually calculated to match local changes in sensory input? Changes in body mechanics, local sensory inputs, and/or prediction of upcoming events are considered important components of postural control during normal daily activities. Clarification of how each of these mechanisms influence the reaction to postural instability should assist clinicians in evaluating causes of falling and balance disturbances. Such clarification will improve interventions directed toward training patients to compensate for, or adapt to postural disorders. To accomplish this goal, both normal subjects and bilateral labyrinthectomized patients will be tested. Subjects will be rotated and translated in the pitch plane in a variety of postural states (e.g., sitting, standing) with the axis of rotation either at the head, the center of mass, or the ankle. Subjects will also be perturbed with head and/or trunk fixed when standing on a posture platform that can be servoed to the ankle angle. This will permit selective elimination of vestibular, neck, and ankle proprioceptive inputs in order to measure the effects of each sensory signal on the response. Subjects will be asked either to voluntarily stabilize against the perturbing force, or to distract themselves with mental arithmetic. Two stimulus waveforms will be used. A discrete, predictable ramp wave will provide information about the latency and magnitude of the relevant responses. Pseudorandom ramps will evoke more automatic characteristics of the response. Specific questions relating to the overall goal include studies that identify the mechanical parameters regulating the spatial and temporal sequence of stabilizing reactions, examine the influence of anticipation on patterns of muscle activation, and determine the linear realtions between sensory signals and functional stability.