Abstracts

Rationale: Periodic lateralized epileptiform discharges (PLEDs) are seen with a variety of neurological conditions. They may be seen in the acute state and sometimes represent an ictal pattern. The significance of PLEDs to predict prognosis may in part be due to limited amount of EEG in these patients to observe patterns of evolution and persistence of PLEDS. We reviewed patients with PLEDs during continuous EEG to ascertain relationship of morbidity to etiology and patterns of PLEDs. Methods: Retrospective review of patients undergoing continuous EEG in our hospital from March, 2008 to September, 2009 who had PLEDs on EEG. Patient outcomes and subsequent EEGs were reviewed and analyzed which were recorded during and after a critical illness. Results: Of 166 patients who had cEEG, 11(7%) patients had PLEDs pattern on EEG. Of the patients with PLEDs,7 patients died (64%) and of those that died the etiology consisted anoxic brain injury(42%), sepsis (42%), and bacterial meningitis (14%). Survivors of illness showing PLEDs (4 patients) had focal stroke in 3 and alcohol as etiology in one. Seizure patterns were seen slightly more frequently in the survivor group with no other difference in PLED patterns which persisted in many even after acute illness resolved or deficits persisted. Conclusions: PLED patterns in themsleves are associated with acute illness but not may be able to prognosticate based on EEG features only. The occurrence of a more diffuse brain involvement by the underlying etiology copmpared to a focal vascular insult rather than the acute nature may be of more prognostic significance when occurring with PLEDs.