Extrarolandic Origin of Spike and Myoclonus Activity in Epilepsia Partialis Continua: A Magnetoencephalographic and Positron Emission Tomography Study

The dipole sources of interictal spike activity were localized and the myoclonus activity back-averaged by combined magnetoencephalography and surface electromyographic measurements in a child who had epilepsia partialis continua without a structural brain lesion. Dipole sources were matched with metabolic information obtained from interictal 5-fluoro-o-glucose positron emission tomography (PET) and superimposed onto highresolution magnetic resonance images. Dipole sources of interictal epileptic discharges clustered within the inferior parietal cortex, which also showed a regional hypermetabolism on PET scans. The dipole sources of reafferent activity following myocloni in the postcentral gyrus were associated with a local hypometabolism.