Abstracts

Rationale: Currently scant data exist on the time necessary to detect epileptiform discharges in patients being monitored in epilepsy monitoring units (EMUs). Methods: Twenty five consecutive electroencephalograms (EEGs) recorded in the EMU were selected during a one month period. EEGs were included regardless of age, sex or reason for admission. Two epileptologists as well as automated spike detectors were used to review the EEGs in their entirety. The first epileptiform discharge was identified and confirmed in a blinded fashion. Results: Forty-eight percent (12/25) of the EMU studies showed no epileptiform discharges. In 56% (14/25), epileptiform discharges were detected during the course of the study. Of those that showed epileptiform abnormalities, 14% (2/14) demonstrated spikes/ sharp waves after more than 1 hour of recording. Whereas in 86% (12/14), epileptiform abnomralities were seen in less than 15 minutes of recording time. Conclusions: Epileptiform abnormalities most often declare themselves within the first 15 minutes of a recording. However, occasionally epileptiform discharges do not appear until well into an EEG recording.