MAGNETOENCEPHALOGRAPHY UNDER GENERAL ANESTHESIA FOR CHILDREN WITH EPILEPSY
Abstract number :
1.157
Submission category :
Year :
2003
Submission ID :
2520
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Ayako Ochi, Hiroshi Otsubo, Elizabeth Pang, Shelly K. Weiss, Amrita Hunjan, Irene Elliott, Sheelagh M. Kemp, Sylverster Chuang, O. Carter Snead III Neurology, The Hospital for Sick Children, Toronto, ON, Canada; Anaesthesia, The Hospital for Sick Children
Magnetoencephalography (MEG) has been increasingly used as a diagnostic tool for patients with epilepsy. The accuracy of the MEG source localization onto MRI is dependent upon the ability of the patient to keep still in the dewar. Thus, children with epilepsy who are uncooperative require general anesthesia (GA) for the MEG and MRI studies. GA has a tendency to eliminate the epileptic discharges. We evaluated the MEG studies under GA compared to prolonged video-EEG (VEEG) results in children with epilepsy.
A total of 185 pediatric patients with epilepsy underwent MEG study with simultaneous 19-channel scalp-EEG at The Hospital for Sick Children in Toronto between August 2000 and March 2003. These patients also had VEEG for 16-96 hours with 19-scalp electrodes. Twenty-two of 185 children underwent GA for MEG and MRI studies. Propofol and remifentanil were used for GA. Whole-head 151-channel gradiometers were used for MEG recording (CTF, Port Coquitlam, BC, Canada). We performed MEG dipole analysis using single moving dipole modeling. We compared the interictal discharges among MEG, simultaneous EEG and VEEG recording. Less than 6 MEG dipoles were defined as being inconclusive MEG results.
Twenty-two children consisted of 10 girls and 12 boys. Age at time of MEG study ranged between 7 months and 9 years (mean [plusmn] SD, 4.6 [plusmn] 2.6 years). Age of seizure onset ranged from one day of life to 3 1/2 years (mean [plusmn] SD, 0.9 [plusmn] 1.0 years). Nineteen had MRI abnormalities. There were no interictal MEG spikes in 4 patients and less than 6 MEG dipoles in two. In these 6 patients with less than 6 MEG dipoles, VEEG captured intermittent interictal spike-waves. The remaining 16 patients showed more than or equal 6 MEG dipoles. In these 16 patients, VEEG showed continuous interictal spike-waves in 6, intermittent spike-waves in 8, and no spikes in two. Sensitivity of MEG under GA was 73 % (16 out of 22 patients). The efficacy of MEG results under GA, which provided valuable information for epilepsy management, was 63% (14 out of 22 patients).
GA influenced interictal epileptiform discharges in short-term MEG recording. Continuous spike-waves can exist under GA and be localized by MEG, although sensitivity appears to be decreased by GA. Short-term MEG study under GA has a certain disadvantage in collecting interictal spikes compared to the prolonged video-EEG monitoring in uncooperative children with epilepsy.