Abstracts

Magetoencephalography (MEG) has become increasingly useful as a valid clinical tool in the assessment of patients with epilepsy. The clinical MEG lab at The Hospital for Sick Children, (Toronto, Ontario) focuses specifically in examining patients under the age of 18 years. Infants and young , children have been reported with intractable epilepsy, as catastrophic thus requiring epilepsy surgery. This paper reports the data of MEG in infants under the age of 3 years, with catastrophic epilepsy., We studied 18 children ranging in age from 6 months to 3 years between 2001 and 2006. We used 151 channel MEG (VSM MED Tech, Port Coquitlam, B.C.) with simultaneous EEG . We recorded 15 to 20 data sets, 2 minutes in duration by capturing spontaneous MEG and EEG activities. We performed somatosensory evoked fields (SEF) with median nerve stimulation in all patients. In order to successfully perform MEG and MRI and minimize movement artifacts, we performed studies under general anesthesia (GA) using low dose Propofol and Remi fentanyl in 13 patients, midazolam drip in one patient, and excessive sleep deprivation [gt] 12 hours in 4 patients., Fourteen of the 18 patients had well localized SEF[apos]s bilaterally. In one patient SEF was identified on one side. The other three patients failed to present SEF[apos]s. MEG spikes were identified in 13 patients and 5 patients did not present with any MEG spikes . MEG spike sources were localized in clusters in 10 patients and in scatters in 3 patients. We performed epilepsy surgery in five patients using intraoperative neuronavigation system with MEG dipole localization. 3 out of the 5 patients are seizure free., Performing MEG and MRI in infants under the age of 3 years can be very challenging because of a closed magnetically shielded room and sedation. We established certain preparation methods for the collection of MEG data in a reproducible and consistent manner. MEG analysis localized accurate epileptic dipoles and functional mapping in most of the infants. In infants with catastrophic and intractable epilepsy, MEG can be utilized as a diagnostic tool in the understanding of epileptic brain activities in the developing brain and also assist in the decision for potential epilepsy surgery.,