Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland.
Human Threshold Research Group, Lawson Health Research Institute, London, ON, Canada.
J Neural Eng. 2024 Aug 2;21(4). doi: 10.1088/1741-2552/ad658f.
. Normal function of the vestibular system can be disturbed using a noninvasive technique called electrical vestibular stimulation (EVS), which alters a person's sense of balance and causes false sensations of movement. EVS has been widely used to study the function of the vestibular system, and it has recently gained interest as a therapeutic tool to improve postural stability and help those suffering from vestibular dysfunction. Yet, understanding of how EVS stimulates the vestibular system, the current intensity needed to produce an effect and the frequencies at which it occurs have remained unclear.. The effect of EVS on postural sway was examined in five participants using sinusoidal alternating current with time-varying amplitude from 0 to 1.5 mA and frequency from 0.1 to 10 Hz for three electrode configurations. Dosimetry of the current flow inside the head was conducted using anatomically realistic computational models created individually for each subject based on magnetic resonance imaging data. An estimate for the minimal field strength capable of affecting the vestibular system was calculated with the finite element method.. Bipolar EVS at frequencies up to 10 Hz caused harmonic full-body swaying, and the frequency of the sway was the same as that of the stimulation current. The size of the sway was amplified by increasing the current intensity. Dosimetry modeling indicated that, for 0.2 mA current, the average electric field strength in the vestibular system was approximately 10-30 mV m, depending on the electrode montage. The size of the measured postural sway was proportional to the montage-specific electric field strength in the vestibular system.. The results provide insight to EVS's working mechanisms and improve its potential as a tool to study the sense of balance.
. 前庭系统的正常功能可以通过一种称为电前庭刺激（EVS）的非侵入性技术来干扰，这种技术改变了人的平衡感，导致虚假的运动感。EVS 已被广泛用于研究前庭系统的功能，最近作为一种治疗工具引起了人们的兴趣，以提高姿势稳定性并帮助那些患有前庭功能障碍的人。然而，人们对 EVS 如何刺激前庭系统、产生效果所需的当前强度以及发生的频率仍不清楚。.. 本研究使用时变幅度为 0 至 1.5 mA、频率为 0.1 至 10 Hz 的正弦交流电流，通过三种电极配置，在五名参与者中检查了 EVS 对姿势摆动的影响。使用基于磁共振成像数据为每个受试者单独创建的解剖学逼真计算模型进行头部内部电流流动的剂量测定。使用有限元法计算了估计能够影响前庭系统的最小场强。.. 高达 10 Hz 的双极 EVS 引起全身体谐摆动，摆动的频率与刺激电流的频率相同。通过增加电流强度来放大摆动的幅度。剂量测定建模表明，对于 0.2 mA 的电流，前庭系统中的平均电场强度约为 10-30 mV·m，具体取决于电极布置。测量的姿势摆动幅度与前庭系统中特定于蒙太奇的电场强度成正比。.. 这些结果提供了对 EVS 工作机制的深入了解，并提高了其作为研究平衡感的工具的潜力。
