Donovan Kara M, Adams Joshua D, Park Ki Yun, Demarest Phillip, Tan Gansheng, Willie Jon T, Brunner Peter, Gorlewicz Jenna L, Leuthardt Eric C
Department of Biomedical Engineering, Washington University, St. Louis, Missouri, United States of America.
Division of Neurotechnology, Washington University School of Medicine, St. Louis, Missouri, United States of America.
PLoS One. 2025 May 29;20(5):e0310917. doi: 10.1371/journal.pone.0310917. eCollection 2025.
Vibration offers a potential alternative modality for transcutaneous auricular vagus nerve stimulation (taVNS). However, mechanisms of action are not well-defined. The goal of this pilot study was to evaluate the potential of vibrotactile stimulation of the outer ear as a method for activating central brain regions similarly to established vagal nerve stimulation methods. Seven patients with intractable epilepsy undergoing stereotactic electroencephalography (sEEG) monitoring participated in the study. Vibrotactile taVNS was administered across five vibration frequencies (2, 6, 12, 20, and 40 Hz) following a randomized stimulation pattern with 30 trials per frequency. Spectral coherence during stimulation was analyzed across theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), and broadband gamma (70-170 Hz) frequency bands. At the group level, vibrotactile taVNS significantly increased coherence in theta (effect sizes 6 Hz: r = 0.311; 20 Hz: r = 0.316; 40 Hz: r = 0.264) and alpha bands (effect sizes 20 Hz: r = 0.455; 40 Hz: r = 0.402). Anatomically, multiple limbic brain regions exhibited increased coherence during taVNS compared to baseline. The percentage of total electrode pairs demonstrating increased coherence was also quantified at the individual level. Twenty Hz vibration resulted in the highest percentage of responder pairs across low-frequency coherence measures, with a group-average of 33% of electrode pairs responding, though inter-subject variability was present. Overall, vibrotactile taVNS induced significant low-frequency coherence increases involving several limbic system structures. Further, parametric characterization revealed the presence of inter-subject variability in terms of identifying the vibration frequency with the greatest coherence response. These findings encourage continued research into vibrotactile stimulation as an alternative modality for noninvasive vagus nerve stimulation.
振动为经皮耳迷走神经刺激（taVNS）提供了一种潜在的替代方式。然而，其作用机制尚未明确。本初步研究的目的是评估对外耳进行振动触觉刺激作为一种激活中枢脑区的方法的潜力，该方法类似于已确立的迷走神经刺激方法。七名正在接受立体定向脑电图（sEEG）监测的难治性癫痫患者参与了该研究。按照随机刺激模式，在五个振动频率（2、6、12、20和40赫兹）下进行振动触觉taVNS，每个频率进行30次试验。在刺激期间，对theta（4 - 8赫兹）、alpha（8 - 13赫兹）、beta（13 - 30赫兹）和宽带伽马（70 - 170赫兹）频段的频谱相干性进行了分析。在组水平上，振动触觉taVNS显著增加了theta频段（效应大小6赫兹：r = 0.311；20赫兹：r = 0.316；40赫兹：r = 0.264）和alpha频段（效应大小20赫兹：r = 0.455；40赫兹：r = 0.402）的相干性。在解剖学上，与基线相比，多个边缘脑区在taVNS期间表现出相干性增加。在个体水平上也对显示相干性增加的总电极对的百分比进行了量化。20赫兹振动在低频相干性测量中导致反应对的百分比最高，组平均有33%的电极对产生反应，尽管存在个体间差异。总体而言，振动触觉taVNS引起了涉及多个边缘系统结构的显著低频相干性增加。此外，参数表征揭示了在确定具有最大相干性反应的振动频率方面存在个体间差异。这些发现鼓励继续研究振动触觉刺激作为非侵入性迷走神经刺激的替代方式。
