Abstracts

Rationale: Efforts have been made to identify predictors to distinguish between epileptic seizures (ES) and non-epileptic seizures (NES) in patients admitted to epilepsy monitoring units (EMU). Typical events while in the hospital, but prior to or during lead placement for video EEG (pre-monitoring events or PME) have been previously thought to represent psychogenic NES¹.Methods: Retrospective review of 112 patients admitted to the EMU at St. Luke s Episcopal Hospital in Houston, TX from April 2010 to May 2011 was performed. Twenty patients (18%) admitted were found to have their typical events prior to or during electrode lead placement. We compared the number of patients that were found to have ES and those found to have NES based on similar events subsequently recorded during monitoring. Age, baseline seizure frequency, time to first event, number of event types, number of antiepileptic drugs prescribed, total number of events captured, and number of events during the first 24 hours were compared between the two groups to identify predictors or characteristics to distinguish between patients with NES and ES.Results: In our patient sample, 9/20 (45%) had ES, 9/20 (45%) had NES, and 2/20 (10%) had both. This is contrary to previous publications, which have identified all patients with PME as having NES1 . In addition, the number of events in the first 24 hours in these patients significantly differed between those with ES and NES (2.375 and 5.857, respectively, p=0.0339). Baseline seizure frequency was also significantly different between the two groups (61.083 per month (ES) and 19.5 per month (NES), p<0.001). Otherwise, age, time to first event, total number of events captured (8.875 v 7), number of AEDs (1.89 v 1.78) were not found to be statistically different between those with ES and NES respectively.Conclusions: Contrary to previous studies, PMEs include both ES and NES. PMEs should not be considered a reliable predictor for NES and video EEG monitoring is necessary to make an accurate diagnosis.