[Epidural electrodes could safely delineate ictal focus of hyperkinetic seizure in intractable frontal lobe epilepsy].

A 42-year-old male had intractable hyperkinetic seizure since childhood. Bottom-of-sulcus dysplasia was shown by MRI to be most likely an ictal focus, whereas ictal semiology suggested possible focus in the left frontal cortex. Scalp-recorded EEG could not delineate ictal EEG change at all partly because of violent hyperkinetic seizure, and thus intracranial EEG study by epidural electrodes was conducted as the best procedure for the safety concern. It showed ictal focus over the bottom-of-sulcus dysplasia and thus it was completely resected with seizure free more then 20 years until now. It was concluded that epidural electrodes are regarded as safe invasive recording method especially for violent hyperkinetic seizure, and that can provide us with essential information before epilepsy surgery.