Predicting Favorable Surgical Outcome in Patients Who Underwent Vagus Nerve Stimulation Using Gradient Magnetic-Field Topography Analysis of Magnetoencephalography
Abstract number :
2.046
Submission category :
3. Neurophysiology / 3D. MEG
Year :
2019
Submission ID :
2421495
Source :
www.aesnet.org
Presentation date :
12/8/2019 4:04:48 PM
Published date :
Nov 25, 2019, 12:14 PM
Authors :
Akitake Okamura, Institute of Biomedical & Health Sciences, Hiroshima University; Koji Iida, Institute of Biomedical & Health Sciences, Hiroshima University; Akira Hashizume, Institute of Biomedical & Health Sciences, Hiroshima University; Kota Kagawa, In
Rationale: Objective: Gradient magnetic field topography (GMFT) can express the spatial spreading of epileptic spikes over time to analyze the data of magnetoencephalography (MEG). We examined favorable factors for postoperative outcome of vagus nerve stimulation (VNS) using GMFT. Methods: Methods: We analyzed 14 VNS-implanted patients (age 9-53 years) who underwent pre- and post-surgical MEG analysis in our institute between March 2011 and January 2016. The postoperative MEG was at an average of 23 months after the VNS implantation. We evaluated the patients’ postoperative outcome using McHugh classification; class I & II as favorable (Group A, 8 patients), and class III-V as poor outcome (Group B, 6 patients). We used temporal signal-space separation algorithm to remove VNS-derived artifact. We evaluated spread of each spike using GMFT before and after spike peak. According to the changes in the epileptic activity region before and after VNS implantation, we compared the total number of spikes and the proportion of bilaterally-spreading spike (P-BS) between the both groups. Results: Results: While the total number of spike in the all cases significantly reduced from before to after VNS implantation (mean 77.6 (4 - 575) vs. mean 25.9 (0 - 59), p = 0.042), P-BS did not change (mean 0.40 (0 - 0.84) vs. mean 0.30 (0 - 0.90), p = 0.22). Preoperative total numbers of spikes did not differ between the two groups (Group A: mean 45.5 (6-131) vs. Group B: mean 120.5 (4 - 575), p = 0.75). The preoperative number of spikes did not predict postoperative outcome. Group A showed significantly higher preoperative P-BS than Group B (mean 0.61 (0 - 0.84) vs. mean 0.12 (0 - 0.50), p = 0.019). High preoperative P-BS predicted good postoperative outcome (p < 0.01, R-squared = 0.60). Conclusions: Conclusion: In analysis of MEG before and after VNS implantation, GMFT successfully evaluated epileptic activity spreading in both hemispheres. The high preoperative P-BS may serve as a favorable postoperative outcome factor. Funding: No funding
Neurophysiology