Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts.
Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear, Boston, Massachusetts.
J Neurophysiol. 2021 Feb 1;125(2):672-686. doi: 10.1152/jn.00168.2020. Epub 2021 Jan 27.
Controlling posture requires continuous sensory feedback about body motion and orientation, including from the vestibular organs. Little is known about the role of tilt vs. translation vs. rotation vestibular cues. We examined whether intersubject differences in vestibular function were correlated with intersubject differences in postural control. Vestibular function was assayed using vestibular direction-recognition perceptual thresholds, which determine the smallest motion that can be reliably perceived by a subject seated on a motorized platform in the dark. In , we measured thresholds for lateral translation, vertical translation, yaw rotation, and head-centered roll tilts. In , we measured thresholds for roll, pitch, and left anterior-right posterior and right anterior-left posterior tilts. Center-of-pressure (CoP) sway was measured in sensory organization tests () and Romberg tests (). We found a strong positive relationship between CoP sway and lateral translation thresholds but not CoP sway and other thresholds. This finding suggests that the vestibular encoding of lateral translation may contribute substantially to balance control. Since thresholds assay sensory noise, our results support the hypothesis that vestibular noise contributes to spontaneous postural sway. Specifically, we found that lateral translation thresholds explained more of the variation in postural sway in postural test conditions with altered proprioceptive cues (vs. a solid surface), consistent with postural sway being more dependent on vestibular noise when the vestibular contribution to balance is higher. These results have potential implications for vestibular implants, balance prostheses, and physical therapy exercises. Vestibular feedback is important for postural control, but little is known about the role of tilt cues vs. translation cues vs. rotation cues. We studied healthy human subjects with no known vestibular pathology or symptoms. Our findings showed that vestibular encoding of lateral translation correlated with medial-lateral postural sway, consistent with lateral translation cues contributing to balance control. This adds support to the hypothesis that vestibular noise contributes to spontaneous postural sway.
姿势控制需要不断的本体感觉反馈，包括前庭器官。对于倾斜与平移与旋转前庭线索的作用，知之甚少。我们研究了前庭功能的个体间差异是否与姿势控制的个体间差异相关。前庭功能通过前庭方向识别知觉阈值进行测试，该阈值确定了主体坐在黑暗中机动平台上时可以可靠感知的最小运动。在[实验 1]中，我们测量了侧向平移、垂直平移、偏航旋转和以头为中心的滚动倾斜的阈值。在[实验 2]中，我们测量了滚动、俯仰和左前-右后、右前-左后倾斜的阈值。在感觉组织测试（SOT）和 Romberg 测试（RT）中测量了重心（CoP）摆动。我们发现 CoP 摆动与侧向平移阈值之间存在很强的正相关关系，但 CoP 摆动与其他阈值之间没有这种关系。这一发现表明，前庭对侧向平移的编码可能对平衡控制有很大贡献。由于阈值检测到感觉噪声，我们的结果支持前庭噪声有助于自发性姿势摆动的假设。具体来说，我们发现，在姿势测试条件下，当改变本体感觉线索（相对于固体表面）时，侧向平移阈值解释了更多的姿势摆动变化，这与当前庭对平衡的贡献更高时，姿势摆动更依赖于前庭噪声的假设一致。这些结果对于前庭植入物、平衡假肢和物理治疗运动有潜在的影响。前庭反馈对姿势控制很重要，但对于倾斜线索与平移线索与旋转线索的作用知之甚少。我们研究了没有已知前庭病理或症状的健康人类受试者。我们的发现表明，侧向平移的前庭编码与内侧-外侧姿势摆动相关，这与侧向平移线索有助于平衡控制的假设一致。这进一步支持了前庭噪声有助于自发性姿势摆动的假设。
