Epileptiform activity in children with developmental dysphasia: quantification of discharges in overnight sleep video-EEG.

We present results of analysis of overnight sleep video-EEG in 8 patients with developmental dysphasia and rolandic discharges. We evaluated the incidence of epileptiform discharges (expressed as paroxysmal activity density) at one or more electrodes in different sleep stages in three different periods of the night (after falling asleep, around midnight and before awakening). The difference of paroxysmal activity density was never higher than 21%, indicating that quantifying the discharges in the whole night recording is not necessary. We also showed that two independent foci may differ in the frequency of discharges. We propose a scheme for evaluation of EEG reflecting both frequency and distribution of discharges.