Dipole source analysis of rolandic spikes in benign rolandic epilepsy and other clinical syndromes.

Dipole source analysis of rolandic spike-and-wave complexes was performed in 48 children. The estimated source of the rolandic spike, of the trough between the spike and the following slow wave, and of the slow wave appeared to have the same position but had a small significant difference in orientation. Despite the heterogeneity of associated clinical syndromes, there were no clear differences between the clinical categories of patients regarding the localization and the orientation of the sources of the rolandic spike, trough and slow wave. The presence of a second source could explain the ascending phase of the rolandic spike in 19 children. This combination of two sources corresponded with the "double-spike phenomenon" that had been found previously by sequential brain mapping and which was associated with epilepsy. The preceding spike source and the source of the rolandic spike-and-wave complex were found to have the same position but a different orientation. A hypothetical explanation is proposed in which the presence of the rolandic spike-and-wave complex alone is insufficient to account for the clinical symptomatology. Both the preceding spike source and the source of the rolandic spike-and-wave complex, representing two separate, nearby but differently oriented populations of neurones in the inferior part of the rolandic cortex, is necessary for the development of epileptic manifestations.