Ernst Lia D, Steffan Paul J, Srikanth Priya, Wiedrick Jack, Spencer David C, Datta Proleta, Joseph Navya M, Wernovsky Magda, Becker Danielle A
Department of Neurology, Oregon Health & Science University (OHSU), Portland, Oregon, U.S.A.
Institute of Neuroscience, University of Oregon, Eugene, Oregon, U.S.A.
J Clin Neurophysiol. 2023 Jan 1;40(1):37-44. doi: 10.1097/WNP.0000000000000847. Epub 2021 Apr 7.
Both vagal nerve stimulation (VNS) and responsive neurostimulation (RNS System) are treatment options for medically refractory focal epilepsy. The mechanism of action of both devices remains poorly understood. Limited prior evidence suggests that acute VNS stimulation may reduce epileptiform activity and cause EEG desynchronization on electrocorticography (ECoG). Our study aims to isolate effects of VNS on ECoG as recorded by RNS System in patients who have both devices, by comparing ECoG samples with and without acute VNS stimulation.
Ten 60-second ECoGs each from 22 individuals at 3 epilepsy centers were obtained-5 ECoGs with VNS "off" and 5 ECoGs with VNS "on." Electrocorticograps containing seizures or loss of telemetry connection artifact were excluded from analysis (total of 169 ECoGs were included). Electrocorticographs were analyzed for differences in spectral content by generating average spectrograms for "on" and "off" states and using a linear mixed-effects model to isolate effects of VNS stimulation.
Acute VNS stimulation reduced average power in the theta band by 4.9%, beta band by 3.8%, and alpha band by 2.5%. The reduction in theta power reached statistical significance with a P value of <0.05.
Our results provide evidence that acute VNS stimulation results in desynchronization of specific frequency bands (salient decrease in theta and beta bands, smaller decrease in alpha band) in ECoGs recorded by the RNS device in patients with dual (VNS and RNS) neurostimulators. This finding offers support for desynchronization as a theorized mechanism of action of VNS. Further research may lead to future improved neurostimulator efficacy by informing optimal stimulation programming parameters.
迷走神经刺激（VNS）和反应性神经刺激（RNS系统）均为药物难治性局灶性癫痫的治疗选择。两种设备的作用机制仍知之甚少。先前有限的证据表明，急性VNS刺激可能会降低癫痫样活动，并导致皮层脑电图（ECoG）出现脑电图去同步化。我们的研究旨在通过比较有或无急性VNS刺激时的ECoG样本，分离VNS对同时植入这两种设备的患者经RNS系统记录的ECoG的影响。
从3个癫痫中心的22名个体中各获取10段60秒的ECoG，其中5段VNS“关闭”时的ECoG和5段VNS“开启”时的ECoG。分析时排除包含癫痫发作或遥测连接丢失伪迹的皮层脑电图（共纳入169段ECoG）。通过生成“开启”和“关闭”状态的平均频谱图并使用线性混合效应模型来分离VNS刺激的影响，对皮层脑电图的频谱内容差异进行分析。
急性VNS刺激使θ频段平均功率降低4.9%，β频段降低3.8%，α频段降低2.5%。θ功率的降低具有统计学意义，P值<0.05。
我们的结果表明，急性VNS刺激会导致在同时植入VNS和RNS神经刺激器的患者中，经RNS设备记录的ECoG中特定频段去同步化（θ和β频段显著降低，α频段降低幅度较小）。这一发现为去同步化作为VNS的一种理论作用机制提供了支持。进一步的研究可能通过为优化刺激编程参数提供信息，从而提高未来神经刺激器的疗效。
