Gavriilidou Alkistis, Mylonas Vasileios, Tsalavoutas Ioannis, Konstantakos Vasileios, Psillas George, Wuehr Max, Hatzitaki Vassilia
Motor Behavior and Adapted Physical Activity Laboratory, Aristotle University, Thessaloniki, Greece.
Present address: Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
Exp Brain Res. 2024 Dec 23;243(1):33. doi: 10.1007/s00221-024-06979-5.
Imperceptible noisy galvanic vestibular stimulation (nGVS) improves standing balance due to the presence of stochastic resonance (SR). There is, however, a lack of consensus regarding the optimal levels and type of noise used to elicit SR like dynamics. We aimed to confirm the presence of SR behavior in the vestibular system of young healthy adults by examining postural responses to increasing amplitudes of white and pink noise stimulation scaled to individual cutaneous perceptual threshold. Forty (40) healthy young participants (19 males, 25.1 ± 5.6 years) were randomly divided into a group that received nGVS with white (WHITE group) or pink noise (PINK group). Participants performed a cutaneous perceptual threshold detection task followed by 8 trials of quiet standing and eyes closure (60s) with nGVS applied during the last 30s. Balance stabilization was quantified in the ratio of the stimulus versus pre-stimulus Centre of Pressure (CoP) 90% ellipse area, Root Mean Square (RMS) and mean velocity. Cutaneous perceptual threshold was similar across groups. Group analysis confirmed that the mean CoP velocity increased across nGVS intensities, particularly for the PINK group while the other two variables remained unchanged. Single subject analysis indicated that 55% of WHITE and 30% of PINK group participants showed an SR-like response judged by three experts. Results are puzzling with respect to the presence of SR-like response dynamics in young healthy adults and highlight the need for further research using individual calibrated stimulus intensities. White noise seems more effective than pink noise in revealing an SR-like response to nGVS.
由于存在随机共振（SR），难以察觉的噪声性前庭电刺激（nGVS）可改善站立平衡。然而，对于用于引发类似SR动力学的最佳噪声水平和类型，目前尚无共识。我们旨在通过检查对按个体皮肤感知阈值缩放的白噪声和粉红噪声刺激幅度增加的姿势反应，来确认年轻健康成年人前庭系统中SR行为的存在。40名健康年轻参与者（19名男性，年龄25.1±5.6岁）被随机分为接受白噪声nGVS的组（白组）或粉红噪声nGVS的组（粉组）。参与者先进行皮肤感知阈值检测任务，然后进行8次安静站立并闭眼（60秒）的试验，在最后30秒施加nGVS。通过刺激与刺激前压力中心（CoP）90%椭圆面积、均方根（RMS）和平均速度的比值来量化平衡稳定性。各组间皮肤感知阈值相似。组分析证实，平均CoP速度随nGVS强度增加，尤其是粉组，而其他两个变量保持不变。单受试者分析表明，三位专家判断，白组55%的参与者和粉组30%的参与者表现出类似SR的反应。关于年轻健康成年人中类似SR反应动力学的存在，结果令人困惑，并突出了使用个体校准刺激强度进行进一步研究的必要性。在揭示对nGVS的类似SR反应方面，白噪声似乎比粉红噪声更有效。
