title: Magnetoencephalographic analysis of bilaterally synchronous discharges in benign rolandic epilepsy of childhood.
abstract: The purpose of this study was to examine the spatial and temporal relationship between bilateral foci of bilaterally synchronous discharges in benign rolandic epilepsy of childhood (BREC) using a whole-scalp neuromagnetometer. We simultaneously recorded interictal magnetoencephalographic (MEG) and electroencephalographic (EEG) signals in six children with BREC. Interictal spikes were classified into three groups: bilaterally synchronous discharges (BSDs), unilateral discharges on right side (UD-R), and unilateral discharges on left side (UD-L). We used equivalent current dipole (ECD) modelling to analyse the cortical sources of interictal spikes. Both BSDs and UDs were found in Patients 1-4, whereas only UDs were identified in Patients 5 and 6. The ECDs of interictal spikes were located in rolandic regions, 10-20mm anterior and lateral to hand somatosensory cortices. Multi-dipole analysis of BSDs showed two ECDs in homotopic motor areas of the hemispheres. During BSDs, the right-sided activation preceded the left-sided activation by 15-21 milliseconds in Patients 1 and 2. In Patients 3 and 4, the activation occurred 17-20 milliseconds earlier in the left than the right hemisphere. Within the same hemisphere, the sources of BSDs and UDs were located in similar areas. In conclusion, our results imply the cortical epileptogenicity in bilateral perirolandic areas in BREC. The sequential activation during BSDs in both hemispheres suggest the existence of synaptic connections, possibly via the corpus callosum, between bilateral irritative foci.
authors.affiliation: Integrated Brain Research Unit, Department of Medical Research and Education, Taipei Veterans General Hospital, No 201, Sector 2, Shih-Pai Road, Taipei 11217, Taiwan, ROC. yylin@vghtpe.gov.tw
authors.forename: Yung-Yang
authors.initials: YY
authors.lastname: Lin
authors.forename: Kai-Ping
authors.initials: KP
authors.lastname: Chang
authors.forename: Jen-Chuen
authors.initials: JC
authors.lastname: Hsieh
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Yeh
authors.forename: Hsiang-Yu
authors.initials: HY
authors.lastname: Yu
authors.forename: Shang-Yeong
authors.initials: SY
authors.lastname: Kwan
authors.forename: Der-Jen
authors.initials: DJ
authors.lastname: Yen
authors.forename: Chun-Hing
authors.initials: CH
authors.lastname: Yiu
authors.forename: Riitta
authors.initials: R
authors.lastname: Hari
mesh_terms: D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology; D002648:Child; D004558:Electric Stimulation; D004569:Electroencephalography / Q000145:classification / Q000706:statistics & numerical data; D019305:Epilepsy, Rolandic / Q000175:diagnosis* / Q000503:physiopathology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008959:Models, Neurological; D012535:Scalp; D013997:Time Factors