Preoperative Evaluation for Indication of Total Corpus Callosotomy Using Gradient Magnetic Field Topography (GMFT) in Patients With Intractable Epilepsy and Drop Attacks
Abstract number :
1.157
Submission category :
3. Neurophysiology / 3D. MEG
Year :
2018
Submission ID :
498843
Source :
www.aesnet.org
Presentation date :
12/1/2018 6:00:00 PM
Published date :
Nov 5, 2018, 18:00 PM
Authors :
Kota Kagawa, Hiroshima University Hospital; Koji Iida, Hiroshima University Hospital; Akira Hashizume, Hiroshima University Hospital; Masaya Katagiri, Epilepsy Center, Neurological Institute, Cleveland Clinic; Go Seyama, Hiroshima University Hospital; Hir
Rationale: Gradient magnetic field topography (GMFT) for magnetoencephalography (MEG) has been developed to demonstrate magnetic-field gradients of interictal epileptic spikes on a volume-rendered brain surface (1). Previously, we revealed that higher proportion of the anterior bilateral spikes on GMFT is predictive of successful anterior corpus callosotomy in adult patients with drop attacks (2). In this study, we evaluated preoperative GMFT for indication of total corpus callosotomy (TCC) in patients with intractable epilepsy and drop attacks. Methods: Seven patients (age: 2-12 years) were enrolled in this study. All had intractable symptomatic generalized epilepsy with drop attacks. We selected interictal MEG spikes from 30-min recording corresponding to generalized spikes on simultaneously recorded EEG. The MEG spikes were band-pass filtered at 14-50 Hz. We defined areas with a gradient of over 300fT/cm as activated zones (AZ) on GMFT. Based on the AZ distributions at spike peak and at spike onset, we divided the spikes as follows: 1) bilaterally- or unilaterally-spreading, and 2) anteriorly- or posteriorly-originating. We compared the spike proportions of each AZ distribution between group G (four patients with cessation of drop attacks after TCC) and group P (three with residual drop attacks). Results: We analyzed mean of 108.8 (range: 80-138) spikes per patient. The proportion of bilaterally-spreading spikes in group G (75.9±12.7%, mean±SD) was significantly (p=0.0017) higher than that in group P (17.9±11.8%). The proportion of the anteriorly-originating spikes showed no significant difference between the two groups (79.4±16.9% in group G and 54.6±30.9% in group P). Conclusions: GMFT revealed a higher proportion of preoperative bilaterally-spreading spikes in patients with good control of drop attacks after TCC.References(1) Hashizume et al. Gradient magnetic-field topography for dynamic changes of epileptic discharges. Brain Res. 2007;1144:175-179.(2) Kagawa et al. Magnetoencephalography using gradient magnetic field topography (GMFT) can predict successful anterior corpus callosotomy in patients with drop attacks. Clin Neurophysiol. 2016;127:221-229. Funding: Not applicable