Magnetoencephalographic analysis in a case of early-onset benign childhood occipital seizures.

We report a 12-year-old boy who had one seizure comprising deviation of the eyes followed by impairment of consciousness for 30 minutes at the age of 6 years. No visual hallucination or ictal vomiting was observed. Interictal electroencephalography showed repetitive spikes and spike-wave discharges over the left occipital lobe. Magnetoencephalography revealed that the estimated dipoles were clustered in the left cuneus on magnetic resonance imaging, which corresponded to the area of peripheral vision and the associated visual cortex but not to the central visual cortex. Magnetoencephalography is advantageous for determining the electrophysiologic mechanism of early-onset benign childhood occipital seizures.