Ko Li-Wei, Chikara Rupesh Kumar, Chen Po-Yin, Jheng Ying-Chun, Wang Chien-Chih, Yang Yi-Chiang, Li Lieber Po-Hung, Liao Kwong-Kum, Chou Li-Wei, Kao Chung-Lan
Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu 300, Taiwan.
Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 300, Taiwan.
Brain Sci. 2020 Oct 15;10(10):740. doi: 10.3390/brainsci10100740.
Patients with bilateral vestibular hypofunction (BVH) often suffer from imbalance, gait problems, and oscillopsia. Noisy galvanic vestibular stimulation (GVS), a technique that non-invasively stimulates the vestibular afferents, has been shown to enhance postural and walking stability. However, no study has investigated how it affects stability and neural activities while standing and walking with a 2 Hz head yaw turning. Herein, we investigated this issue by comparing differences in neural activities during standing and walking with a 2 Hz head turning, before and after noisy GVS. We applied zero-mean gaussian white noise signal stimulations in the mastoid processes of 10 healthy individuals and seven patients with BVH, and simultaneously recorded electroencephalography (EEG) signals with 32 channels. We analyzed the root mean square (RMS) of the center of pressure (COP) sway during 30 s of standing, utilizing AMTI force plates (Advanced Mechanical Technology Inc., Watertown, MA, USA). Head rotation quality when walking with a 2 Hz head yaw, with and without GVS, was analyzed using a VICON system (Vicon Motion Systems Ltd., Oxford, UK) to evaluate GVS effects on static and dynamic postural control. The RMS of COP sway was significantly reduced during GVS while standing, for both patients and healthy subjects. During walking, 2 Hz head yaw movements was significantly improved by noisy GVS in both groups. Accordingly, the EEG power of theta, alpha, beta, and gamma bands significantly increased in the left parietal lobe after noisy GVS during walking and standing in both groups. GVS post-stimulation effect changed EEG activities in the left and right precentral gyrus, and the right parietal lobe. After stimulation, EEG activity changes were greater in healthy subjects than in patients. Our findings reveal noisy GVS as a non-invasive therapeutic alternative to improve postural stability in patients with BVH. This novel approach provides insight to clinicians and researchers on brain activities during noisy GVS in standing and walking conditions in both healthy and BVH patients.
双侧前庭功能减退（BVH）患者常伴有平衡失调、步态问题和视振荡。噪声性直流电前庭刺激（GVS）是一种非侵入性刺激前庭传入神经的技术，已被证明可增强姿势和行走稳定性。然而，尚无研究探讨在2Hz头部偏航转动的站立和行走过程中，该技术如何影响稳定性和神经活动。在此，我们通过比较噪声性GVS前后，在2Hz头部转动的站立和行走过程中的神经活动差异，对这一问题进行了研究。我们对10名健康个体和7名BVH患者的乳突施加零均值高斯白噪声信号刺激，并同时用32通道记录脑电图（EEG）信号。我们使用AMTI力板（美国马萨诸塞州沃特敦市先进机械技术公司）分析了站立30秒期间压力中心（COP）摆动的均方根（RMS）。使用VICON系统（英国牛津市Vicon运动系统有限公司）分析了在有和没有GVS的情况下，以2Hz头部偏航行走时的头部旋转质量，以评估GVS对静态和动态姿势控制的影响。对于患者和健康受试者，站立时GVS期间COP摆动的RMS均显著降低。在行走过程中，两组中噪声性GVS均显著改善了2Hz头部偏航运动。相应地，两组在行走和站立时，噪声性GVS后左顶叶的θ、α、β和γ频段的EEG功率均显著增加。GVS刺激后的效应改变了左右中央前回和右顶叶的EEG活动。刺激后，健康受试者的EEG活动变化大于患者。我们的研究结果表明，噪声性GVS是一种改善BVH患者姿势稳定性的非侵入性治疗方法。这种新方法为临床医生和研究人员提供了关于健康和BVH患者在站立和行走条件下噪声性GVS期间大脑活动的见解。
