Patterns of interictal spike propagation across the central sulcus in benign rolandic epilepsy

It has been reported that the rolandic area generating spikes is hyperexcitable, and that rolandic spikes propagate across the central area. However, the pattern of rolandic spike propagation and how the dipolar distribution of the spikes is related to the propagation pattern have not yet been studied. Thirty-nine EEGs from 27 patients with benign rolandic epilepsy (BRE) were examined. Sequential topographic mapping in 4-ms steps was used to analyze the pattern of spike propagation. The locations of maximum negative foci, the presence and distribution of the dipolar field, and the propagation pattern were examined. Dipoles were present in 23 (85.2%) out of 27 patients and in 43 (72.9%) out of 59 foci. Thirty-two foci (54.2%) in 20 patients demonstrated a propagation pattern. The typical pattern consisted of propagation from central to mid-temporal locations across the central sulcus. Most spike foci exhibiting a propagation pattern had a dipolar distribution (87.5%; p=0.008). These results suggest that rolandic spikes originate from sulcal or gyral cortices on either side of the central sulcus, and that spike propagation can ensue by intracortical spreading across the central sulcus.