Although the pathophysiologic mechanism is unknown, there has been long-running debate on whether periodic discharges suchas periodic lateralized epileptiform discharges (PLEDs) and generalized periodic epileptiform discharges are an ictal or interictalEEG pattern. The goal of this review is to give evidence that such periodic discharges on EEG are not ictal phenomenon and justrepresent underlying acute brain damage. This review includes coma with epileptiform EEG pattern and its prognostic andtherapeutic implications. Based on previous reports, rather than taking the view PLEDs represent either an underlying ictal processor an electrographic correlate of neuronal injury, it would be more reasonable that PLEDs are considered as a dynamicpathophysiological state in which unstable neurobiological processes create an ictal-interictal continuum.
