The steady-state postural response to continuous sinusoidal galvanic vestibular stimulation.
The steady-state postural response to continuous sinusoidal galvanic vestibular stimulation.
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DOI：
10.1016/s0966-6362(02)00195-9
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发表时间：
2003-10
期刊：
影响因子：
2.4
通讯作者：
L. Latt;P. Sparto;J. Furman;M. Redfern
中科院分区：
文献类型：
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作者：
L. Latt;P. Sparto;J. Furman;M. Redfern
安静站立时，在乳突之间施加前庭电流刺激(GVS)会引起姿势摆动。本研究的目的是在不同的刺激频率和幅度上表征对连续正弦GVS的姿势摇摆反应。10名受试者闭眼站在测力板上，对乳突上方皮肤进行双耳双极正弦GVS检查。足部压力中心(COP)的位置由测力板记录，而头部位移由磁性位置跟踪系统测量。刺激条件包括四个频率(0.1、0.25、0.45和1.1赫兹)和五个峰值幅度(0.05、0.1、0.25、0.5和1.0 mA)。每个受试者在每个幅度-频率对上都经历了一次试验。此外，每个受试者都经历了三次试验，其中呈现了双频刺激(0.1加0.45赫兹，峰值各为0.5毫安)。这些刺激在所有受试者的额面上引起了摇摆，从COP和头部移位的变化中可以看出。摇摆幅度随刺激频率的增加而减小，随刺激幅度的增加而增加。然而，反应幅度在较高的刺激幅度时饱和。相位滞后随刺激频率的增加而增大。与单频刺激相比，双频刺激的反应在0.1赫兹时降低，而在0.45赫兹时几乎相等。这项研究表明，由于饱和和违反叠加原理，姿态摇摆反应是非线性的。
Galvanic vestibular stimulation (GVS) applied between the mastoids during quiet standing elicits postural sway. The aim of this study was to characterize the postural sway response to continuous sinusoidal GVS across various stimulus frequencies and amplitudes. Binaural bipolar sinusoidal GVS was applied to the skin overlying the mastoid processes of 10 subjects while they stood on a force plate with eyes closed. The position of the center of pressure (COP) at the feet was recorded from a forceplate, while the head displacement was measured with a magnetic position tracking system. The stimulus conditions included four frequencies (0.1, 0.25, 0.45, and 1.1 Hz) and five peak amplitudes (0.05, 0.1, 0.25, 0.5, and 1.0 mA). Each subject experienced one trial at each amplitude–frequency pair. Additionally, each subject underwent three trials in which a dual-frequency stimulus (0.1 plus 0.45 Hz at a peak of 0.5 mA each) was presented. The stimuli elicited sway in the frontal plane in all subjects, as evidenced by changes in the displacement of the COP and head. Sway magnitude decreased with increasing stimulus frequency and increased with increasing stimulus amplitude. However, the response magnitude saturated at higher stimulus amplitudes. Phase lag increased with increasing stimulus frequency. The response to the dual-frequency stimulus was reduced at 0.1 Hz and nearly equal at 0.45 Hz in comparison with the single-frequency responses. This study suggests that the postural sway response is nonlinear due to saturation and violation of the principle of superposition.