REPEATING EEG-VIDEO MONITORING: WHY AND WITH WHAT RESULTS? [P08.065]

Juan C. Muniz, Riverview, FL; Selim Benbadis, Tampa, FL

Conventional electroencephalography (EEG) recording is often inadequate for the diagnosis of patients with recurrent unprovoked seizures.¹ EEG sessions may be too brief to capture important seizure activity, or they may be confounded by nonspecific findings or artifacts. Video EEG monitoring is an important diagnostic tool for patients with epilepsy who do not respond to medication or who have unconfirmed seizure diagnoses, and is the primary activity of epilepsy referral centers.² Although repeat EEG-video monitoring is required for some patients, the reasons for repeat evaluation and the clinical outcomes of these patients have not been extensively studied. The cost of this monitoring is significant, and the utility of repeating this must be examined.

In this poster, Muniz and Benbadis examined the reasons for repeated EEG-video monitoring, and evaluated whether repeating the procedure was useful in the diagnosis or treatment of patients with seizure disorders. The investigators reviewed the data from a total of 1063 EEG-video monitoring sessions that were recorded over a 3-year period at their institution. They identified 43 recordings (4%) that were repeat sessions for patients who had previously undergone EEG video. The most common reason for a repeat procedure was the presence of focal epileptiform discharges without an accompanying seizure when a seizure recording for accurate localization was required for possible surgery. This reason for a repeat EEG video was cited for 14 of the 43 repeat recordings (33%). Other reasons for repeat EEG video included normal interictal EEG sessions with no recorded seizure episodes (9 patients; 21%), surgery failure (6 patients; 14%); the presence of new episodes or episodes of a different type (8 patients; 19%); and recordings of temporal lobe seizures in which the side affected was unclear despite other investigations (6 patients; 14%). The repeated session was useful in answering the clinical question in 35 cases (81%). Although they are uncommon, second EEG-video monitoring sessions produce a high diagnostic yield and should be considered when the clinical question is not resolved following a first session.

References
1. Cascino GD. Video-EEG monitoring in adults. Epilepsia. 2002;43(Suppl 3):80-93.
2. Benbadis SR, O’Neill E, Tatum WO, Heriaud L. Outcome of prolonged video-EEG monitoring at a typical referral epilepsy center. Epilepsia. 2004;45:1150-1153.