Epileptic focus in a case of subcortical band heterotopia: SISCOM and ictal EEG findings

We presented an 11-month-old-girl with subcortical band heterotopia who had focal epilepsy detected by subtraction single photon emission computed tomography (SPECT) coregistered to magnetic resonance (MR) imaging (SISCOM) and ictal electroencephalogram. She manifested cluster of partial seizures composed of asymmetric tonic posturing accompanied by head rotation to the right side. Ictal electroencephalogram showed that paroxysmal discharges were generated from the right parieto-occipital area and spread to surrounding areas. SISCOM revealed hyperperfusion in the overlying cortex of the right superior temporal gyrus, which corresponded to the onset area of ictal epileptiform discharges. These neurofunctional findings corresponded to her clinical seizures. Her seizures were controlled by high-dose phenobarbital therapy. We considered that the patient had focal epilepsy and that the epileptic focus might be in the overlying cortex, but not in the subcortical band.