The presence of short and sharp MEG spikes implies focal cortical dysplasia

MEG epileptiform discharges of short duration and steep tilt characterize FCD, especially when located at the superficial neocortical gyrus. We speculate that this particular spike morphology results from the intrinsic epileptogenicity of FCD. Morphological analysis of MEG spikes can evaluate the etiology of epileptogenic lesions and detect a strong, localized epileptogenic focus such as that typically observed in FCD.