Total intravenous anesthesia affecting spike sources of magnetoencephalography in pediatric epilepsy patients: Focal seizures vs. non-focal seizures

Abstract

Magnetoencephalography (MEG) provides source localization of interictal spikes. This study evaluated the inhibitory effects of propofol on MEG spike sources (MEGSSs) among different types of seizures in patients who underwent two separate MEG studies with and without total intravenous anesthesia (TIVA) using propofol. We studied 19 children (1-14 years; mean, 6.2 years) who had MEG with and without TIVA. TIVA was administered using propofol (0.03-0.06 mg/kg/min) to record MEG with simultaneous EEG. We analyzed number of spikes of MEG and MEGSSs comparing MEG studies done with and without TIVA. Seizures were divided into nine focal seizure (FS) with/without secondary generalization, five epileptic spasm (ES), and five generalized seizure (GS). TIVA significantly decreased the number of MEG spikes/min (from 4.5 to 2.0) in five FS without secondary generalization (p<0.05). The number of MEG spikes/min was significantly lower (1.9) in FS than that in non-FS (ES+GS, 6.1) (p<0.01). MEGSSs without TIVA were clustered in 15 patients (6FS; 4ES; 5GS), scattered in four (3FS; 1ES). MEG under TIVA showed clusters in 10 patients (1FS; 4ES; 5GS), scatters in three (2FS; 1ES) and no MEGSS in six patients with FS. Under TIVA, nine (90%) of ten patients with non-FS showed MEGSSs clusters compared to one (11%) of nine patients with FS (p<0.01). Reduction of MEGSSs occurred in patients with FS under TIVA. Diffuse/generalized spikes in non-FS are not affected by TIVA. Propofol may decrease focal spikes in the epileptic cortex in FS. Cortical hyperexcitability in non-FS group would be stronger or more extensive than that in the FS group of patients.