Objectives. To describe the role and the usefulness of a close EEG monitoring in children with tuberous sclerosis complex (TSC), following a prenatal diagnosis.

Materials and Methods. We present 3 patients with negative familial history, in which fetal ultrasound revealed multiple cardiac rhabdomyomas. We therefore performed a fetal MRI, which was able to detect the presence of subependymal nodules or tubers, allowing a definite prenatal diagnosis of TSC. Soon after birth, all these children began a close EEG monitoring, with awake/sleep EEG performed every 3-4 weeks. All the families have been informed of the high risk of epilepsy of TSC infants in the first year of life, and have been educated to recognize focal subtle seizures and epileptic spasms.

Results. EEG monitoring allowed us to identify focal epileptiform abnormalities early and to observe their evolution towards multifocal abnormalities. In the child who developed epileptic spasms we observed a further evolution toward secondary bilateral synchronization and a tendency toward a pre-hypsarrhythmic pattern the day before the appearance of spasms. The other two children didn’t show seizures at 6 and 7 months of age.

Conclusions. Our data suggests that epileptogenesis is a slow process, taking several weeks or months from the first EEG epileptiform abnormalities to the first seizure. The close EEG monitoring allows us to detect subtle changes in the EEG pattern which might indicate an evolution towards epilepsy. The immediate detection and treatment of seizures is crucial to minimize the possible long-term neurodevelopmental sequelae of early life seizures.