Abstracts

A significant percentage of women with epilepsy (WWE) have reported increased seizure frequency during the perimenstrual period (catamenial epilepsy). We first documented catamenial exacerbation of epileptiform activity using the Responsive Neurostimulator System (RNS) in 2005 [M V Spanaki, et al. Epilepsia 2005;46(Suppl 8):222]. In this study we continuously measured epileptiform activity in two WWE over a total of 17 menstrual cycles., As part of a FDA-approved multicenter feasibility study investigating the safety and potential efficacy of the RNS for epilepsy, we have implanted two WWE who were not good surgical candidates. The patients kept diaries of their menstrual periods. After seizure onset patterns were identified for both patients, detectors were programmed to identify electrocorticogram (ECOG) patterns that occurred prior to clinical seizures. These patterns appear epileptiform and occur frequently, but the vast majority of these bursts do not result in clinical seizures. Detection data from the RNS were then analyzed in multi-day windows around the date of menses onset and compared to detection rates on days exclusive of these perimenstrual windows to determine if the daily detection rate differed between the menstrual and non-menstrual intervals., Data was gathered for 9 and 8 menstrual cycles for patients H and M, respectively. The detection rates for the different windows are shown in the graph.[figure1]The detection data show statistical difference for both patients at window sizes of +/- 3 days relative to the onset of the patient[apos]s menstrual cycle at the alpha = 0.05 level (95% confidence)., The RNS has detection and diagnostic capabilities that allow objective measurement of epileptiform activity over prolonged periods of time in ambulatory patients. Use of RNS has confirmed the existence of perimenstrually exacerbated seizure activity., (Supported by: The RNS is limited by U.S. law to investigational use only. This study was sponsored by NeuroPace, Inc.)