Abstracts

Seizure frequency is known to increase during the perimenstrual period in some women. Thus far, no electrophysiological studies have documented alterations in human brain excitability in relation to menses. In patients implanted with the NeuroPace Inc responsive neurostimulator (RNS ^TM), epileptiform activity can be quantified over the menstrual cycle. FDA and IRB approval were obtained for the investigational use of the RNS. A 22 year-old female with intractable seizures who was not a resective surgery candidate was implanted with the RNS. The RNS detection parameters were optimized during the first month with a line length tool utilized to detect a spike train pattern and a half wave tool for a gamma burst pattern. The RNS provides a detailed record of event detections and records electrocorticograms (ECoGs) that can be viewed by the clinician. The patient received a Data Transmitter (DTR) that could download ECoGs and detailed diagnostic data from their RNS and transmit the data over a telephone line to a secure server for review and analysis via the Internet. These downloads were typically performed by the patient twice per day. During the second month post-implant, the patient[apos]s detection rate per hour was calculated based on these diagnostic data. Detections were graphed according to the patient[apos]s menstrual cycle. Detections were compared during menses as opposed to all other times of the cycle (non-menses). [figure1] The daily detection rates during menses were 27.3[plusmn]5.5 compared to 16.6[plusmn]5.4 at other times of her cycle. The results were significantly different at alpha = 0.05 level (95% confidence) The RNS device provides objective quantification of epileptiform activity which can be correlated with the phases of the menstrual cycle.This preliminary data demonstrates that epileptiform activity in this patient increases in the premenstrual period and remains increased during menses. Ongoing data collection in this and other patients in the RNS Feasibility Clinical Investigation is permitting the first large scale chronic objective evaluation of the nature of epileptiform activity over multiple menstrual cycles in women with catamenial epilepsy. (Supported by NeuroPace, Inc.)