University of Washington Regional Epilepsy Center at Harborview Medical Center

New Equipment at the REC

XL-Tek EEG machines were installed in each of the labs as well as networkable portable units capable of long term monitoring at the bedside with complete digital video coverage. In addition, the Long Term Monitor Unit is fully equipped with fourteen complete systems.

XL-Tek has a sampling rate of 500 samples per second and proves a reliable tool for recording EEG with synching of digital video. The systems come complete with 128-channel processors for intracranial EEG monitoring with grid and strip electrodes. Designed to work together with the Ojemann Stimulator, language and motor mapping are performed with ease in a lab setting. With user-friendly montage and protocol acquisition software, the machines make a smooth transition to the operating room for corticography. This new equipment has been an excellent fit in our demanding clinical environments.

Installation of the new equipment and a move to Harborview's 3 West Neuro Nursing Unit were coordinated simutaneously. The new unit has four private in-patient monitoring rooms offering panoramic views of Elliott Bay as well as three double rooms. This wing was remodeled to accommodate the growing needs of the center.

The Regional Epilepsy Center is the first center in the nation to use Dense Array EEG for longterm EEG monitoring in a clinical setting. The Dense Array, by Electrical Geodesics, Inc. uses a 256 Geodesic Sensor Net. . The closely spaced electrodes and the complete head coverage allows high resolution, 3 dimensional reconstruction of electrical seizure activity. The array includes extensive coverage to the inferior surface of the head including below the ears and the face. No skin abrasion is required in applying the net so the level of discomfort is minimal. The net is suitable for all patient ages and hair types and the issue of salt bridging is non-existent. Whole-head EEG recording allows rapid identification of clinically relevant information. Recordings may be viewed as waveforms, topographic plots, or topographic maps in a variety of montages and channel counts allowing for complete review.

Dense array equipment comes complete with a Geodesic Photogrammetry System. While wearing the net, patients can be placed in the center of the polyhedron-based photogrammetry structure. They can then be photographed with the eleven cameras mounted at each of its vertices, with each camera aligning with specific electrode coordinates. This data can be used for precise source localization and co registration of EEG and MRI. This new equipment not only allows us to not only remain a technologically advanced epilepsy center, but to pioneer valuable new approaches to noninvasively localize and characterize seizures in candidates for epilepsy surgery.