Spike morphology, location, and frequency in benign epilepsy with centrotemporal spikes

The literature on benign epilepsy with centrotemporal spikes reports a constellation of neurophysiologic features in selected populations with heterogeneous methodologies. The aim of this study was to determine the specific electroencephalographic (EEG) features (spike morphology, location, and frequency and associated background slowing) in a broad population-based cohort identified through EEG laboratories. The mean spike frequency in the awake state was 9.3 per minute (95% confidence interval 6.5-12.0), in drowsiness, 21.2 per minute (16.7-25.6); and in sleep, 45.6 per minute (38.3-52.8), where 60% of patients had > 40 discharges per minute. In five patients, spike train rates occupied > 80% of the sleep record, and in nine patients, they occupied 61% to 80%. An ambulatory overnight record did not add new information comparing early-onset sleep with a mean spike frequency of 37.1 per minute (27.3-46.9) with slow-wave sleep, 36.0 per minute (27.3-44.7). Patients with benign epilepsy with centrotemporal spikes have a high spike burden, which can impact on cognitive function.