We could predict good responders to vagus nerve stimulation: a surrogate marker by slow cortical potential shift

Publication date: Available online 15 June 2017
Source:Clinical Neurophysiology
Author(s): Borgil Bayasgalan, Masao Matsuhashi, Tomoyuki Fumuro, Haruhiko Nohira, Naoki Nakano, Koji Iida, Masaya Katagiri, Akihiro Shimotake, Riki Matsumoto, Takayuki Kikuchi, Takeharu Kunieda, Amami Kato, Ryosuke Takahashi, Akio Ikeda
ObjectiveWe investigated whether vagus nerve stimulation (VNS) induces a positive shift of slow cortical potentials (SCPs) in patients with >50% seizure reduction (responders) but not in non-responders.MethodsWe analyzed routine clinical electroencephalograms (EEGs) from 24 patients who were undergoing seizure treatment by VNS. The patients were divided into 2 groups by hardware time constant (TC) of EEG: the TC 10-s group (10 patients) and TC 2-s group (14 patients). We compared SCPs at 5 electrodes (Cz and adjacent ones) between the 2 states of VNS: during stimulation and between stimulations. Seizure reduction was independently judged. Correlation between SCP (positivity or not) and seizure reduction (>50% or not) was estimated.ResultsIn the TC 10-s group, the correlation between SCP and seizure reduction was significant (p < 0.05) (i.e., both good results in 4 and both negative results in 5). In TC 2-s group, the correlation between SCP and seizure reduction was not significant (p = 0.209).ConclusionsA positive shift of SCP recorded by using a TC of 10 s could be a surrogate marker for VNS response.SignificanceSCP could be a biomarker of good responders to VNS.



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