[Periodic lateralized epileptiform discharges. I. Clinical and electroencephalographic aspects]

In a two-years period, from a total of 5481 EEGs, we could select 25, corresponding to 22 patients, with PLEDs (prevalence of 0.45%). The group was composed by 13 males and 9 females, with age ranging from 5 months to 85 years. Main diagnosis was epilepsy of unknown etiology and brain tumor (22% each). The localization of PLEDs was mainly temporal region (54% of the whole group) and more frequent morphology was "delta triphasic wave" (a graphic pattern resembling sharp wave, but with longer duration) (1/3 of total), followed by sharp biphasic wave and sharp wave-slow wave (29% each). Although 9 patients died it was not possible to determine prognostic value of PLEDs specifically for each pathological condition.