Time-related configuration change in benign focal epileptiform discharges of childhood - From a dipole to a negative monopole in a patient with generalized epilepsy

The case of a 6-year-old child with generalized epilepsy and benign focal e pileptiform discharges (BFEDs) of childhood is presented. During his first EEG, performed when he was 6 years old, the patient had three staring episo des accompanied by bursts of 3-Hz spike-and-wave complexes. Interictally, f requent BFEDs were seen, configured as dipoles with a right temporal negati vity and a right frontal positivity. The patient was administered ethosuxim ide and the staring spells disappeared. On follow-up EEG performed 2 years later, no generalized discharges were seen. However, the EEG again showed f requent spikes with a characteristic morphology of BFEDs. This time they we re not configured as dipoles, but as monopoles with a maximum negativity ov er the right frontal region. The change in the generator's orientation over time (from a horizontal to a vertical dipole) is discussed, as well as the prognostic implications of the morphology and configuration of focal spike s. In addition, the authors review the coexistence of BFEDs and 3-Hz spike- and-wave complexes in their patient database.