Use of subdural grids and strip electrodes to identify a seizure focus in children.

For patients with intractable seizures, the best surgical outcome is achieved following precise localization of the seizure focus. Scalp EEG monitoring may be insufficient and chronic subdural invasive EEG monitoring has therefore been advocated. At Children's Hospital in Boston, 31 children had chronic subdural monitoring from January 1990 through June 1994. The average age at implantation was 11 years. Most patients (22) had placement of grid electrodes combined with strip electrodes to map temporal and/or frontal regions bilaterally. Twenty of the patients eventually had a resective procedure based on the findings. During monitoring, cortical stimulations were performed to localize speech and somatosensory areas. There was only one complication, a subdural hematoma in a patient who had had previous surgery. Chronic subdural EEG monitoring is helpful in precisely localizing seizure foci in pediatric patients; it also allows motor and speech mapping and appears to be a safe modality in children.