title: Paradoxical lateralization of parasagittal spikes revealed by back averaging of EEG and MEG in a case with epilepsia partialis continua.
abstract: Our aim was to localize the generator site of parasagittal epileptiform discharges in a patient with epilepsia partialis continua (EPC) in the right leg. We examined a 32-year-old woman with EPC whose conventional EEG did not show any epileptic discharge. We performed the jerk-locked back averaging (JLA) of EEG and magnetoencephalography (MEG) to localize the dipole source of sharp transients. The myoclonic discharges in the right soleus muscle were used as a trigger pulse. JLA revealed consistent EEG and MEG sharp transients that coincided consistently and constantly preceded the myoclonic jerks. JLA of EEG demonstrated sharp waves paradoxically distributed over the vertex and right hemisphere. However, the estimated dipoles of MEG were localized in a restricted area in the primary leg motor area in the left hemisphere, which was closely located in the abnormal lesion on the brain MRI. JLA of MEG is considered to be a useful non-invasive method for localizing the epileptogenic area in EPC even when paradoxical lateralization of electroencephalographic discharges was noted.
authors.affiliation: Department of Neurology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Ayame
authors.initials: A
authors.lastname: Oishi
authors.forename: Shozo
authors.initials: S
authors.lastname: Tobimatsu
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ochi
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Ohyagi
authors.forename: Takamichi
authors.initials: T
authors.lastname: Kubota
authors.forename: Takayuki
authors.initials: T
authors.lastname: Taniwaki
authors.forename: Tomoya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Furuya
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kira
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D004569:Electroencephalography / Q000379:methods*; D004660:Encephalitis / Q000150:complications / Q000276:immunology / Q000503:physiopathology; D017036:Epilepsia Partialis Continua / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000294:innervation / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography / Q000379:methods*; D009044:Motor Cortex / Q000473:pathology / Q000503:physiopathology*; D009207:Myoclonus / Q000209:etiology / Q000473:pathology / Q000503:physiopathology