Atypical Interictal Epileptiform Discharges in Electroencephalography

Background and Purpose A great deal of attention has been focused on “typical” interictal epileptiform discharges (IEDs) in the electroencephalography (EEG) literature. However, there is a paucity of data on “atypical” IEDs, namely, positive sharp waves (PSWs), focal triphasic sharp waves and spikes (FTSWs), sharp slow waves (SSWs), bifid spikes, and “notched” delta. In this present study, we sought to address the pathophysiology, characteristics, and diagnostic significance of “atypical” IEDs in clinical neuroscience.