German Center for Vertigo and Balance Disorders, Ludwig-Maximilians-University, Marchioninistrasse 15, 81377, Munich, Germany.
Schön Klinik Bad Aibling, Bad Aibling, Germany.
J Neurol. 2024 Mar;271(3):1408-1415. doi: 10.1007/s00415-023-12085-3. Epub 2023 Nov 16.
Previous studies indicate that imbalance in patients with bilateral vestibulopathy (BVP) may be reduced by treatment with low-intensity noisy galvanic vestibular stimulation (nGVS).
To elucidate the potential mechanisms underlying this therapeutic effect. In particular, we determined whether nGVS-induced balance improvements in patients are compatible with stochastic resonance (SR)-a mechanism by which weak noise stimulation can paradoxically enhance sensory signal processing.
Effects of nGVS of varying intensities (0-0.7 mA) on body sway were examined in 19 patients with BVP standing with eye closed on a posturographic force plate. We assumed a bell-shaped response curve with maximal sway reductions at intermediate nGVS intensities to be indicative of SR. An established SR curve model was fitted on individual patient outcomes, and three experienced human raters had to judge whether responses to nGVS were consistent with the exhibition of SR.
nGVS-induced reductions of body sway compatible with SR were found in 12 patients (63%) with optimal improvements of 31 ± 21%. In 10 patients (53%), nGVS-induced sway reductions exceeded the minimally important clinical difference (optimal improvement: 35 ± 21%), indicative of strong SR. This beneficial effect was more likely in patients with severe vestibular loss (i.e. lower video head impulse test gain; R = 0.663; p = 0.002) and considerable postural imbalance (baseline body sway; R = 0.616; p = 0.005).
More than half of the assessed patients showed robust improvements in postural balance compatible with SR when treated with nGVS. In particular, patients with a higher burden of disease may benefit from the non-invasive and well-tolerated treatment with nGVS.
先前的研究表明，双侧前庭病变（BVP）患者的平衡失衡可以通过低强度噪声电前庭刺激（nGVS）治疗得到改善。
阐明这种治疗效果的潜在机制。特别是，我们确定了 nGVS 是否可以改善患者的平衡，是否与随机共振（SR）机制兼容，即弱噪声刺激可以悖论地增强感觉信号处理的机制。
在 19 名患有 BVP 的患者中，使用不同强度（0-0.7 mA）的 nGVS 刺激，让他们闭眼站在平衡测试平台上。我们假设存在一个钟形响应曲线，其中中间 nGVS 强度下的身体摆动减小最大，表明存在 SR。根据个体患者的结果拟合了一个已建立的 SR 曲线模型，三位经验丰富的人类评估者必须判断 nGVS 的反应是否符合 SR 的表现。
发现 12 名患者（63%）的身体摆动减少与 SR 兼容，最佳改善幅度为 31±21%。在 10 名患者（53%）中，nGVS 引起的摆动减少超过了最小临床差异（最佳改善：35±21%），表明存在强烈的 SR。这种有益的效果在前庭损失严重的患者中更有可能出现（即视频头脉冲测试增益较低；R=0.663；p=0.002）和明显的姿势失衡（基线身体摆动；R=0.616；p=0.005）。
超过一半的评估患者在接受 nGVS 治疗后，其姿势平衡得到了与 SR 兼容的显著改善。特别是，疾病负担较高的患者可能受益于 nGVS 这种非侵入性且耐受性良好的治疗方法。
