F88. Standardized naming convention for high density EEG

• Published in: Clinical neurophysiology Vol. 129; pp. e99 - e100
• Main Authors: Heine, Walter F., Dobrota, Mary-Ann, Schomer, Donald L., Wigton, Rebekah, Herman, Susan T.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2018
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2018.04.251

High density EEG (hdEEG) systems and Electrical Source Imaging (ESI) techniques have revolutionized our ability to assess the potential sources of epileptiform activity and other EEG features. HdEEG interpretation is limited by lack of standardized electrode position nomenclature and montages. Inefficient visual review of hdEEG remains a major barrier to incorporating these techniques into clinical care. The aim of this project is to propose an electrode map and nomenclature with digitized electrode locations for easy integration with neuroimaging studies and ESI. The 256 channel EEG net (Geodesic Sensor Net, Electrical Geodesics, Inc.) includes electrode locations approximating the International 10–20 and 10–10 systems, but intervening electrodes do not have a standardized location, and many electrodes over the cheeks and face do not have positions defined by the 10–10 or 10–5 systems. We co-registered average 256 channel EEG net electrode positions to the 10–10 positions based on the Montreal Neurologic Institute using Curry 7.0 software. then clustered the 256 electrode locations to their closest 10–10 electrodes tested several channel layouts (montages) allowing rapid transition from global views (all head regions) to focal views (subregions corresponding to 10–10 electrode coordinates). 256 electrode locations were successfully clustered around their closest 10–10 electrode, deemed its cardinal point. All 256 electrodes within a cluster received the same initial letters according to the 10–10 electrode at its center. Within a cluster, the first subscript identified its position either anterior (a) or posterior (p) to the cardinal 10–10 electrode. The second subscript identified its position either superior (s) or inferior (i) to the cardinal 10–10 electrode. The last subscript, numerical, identified the proximity of the nonstandard electrode relative to the cardinal 10–10 electrode, compared to the other nonstandard electrodes in that cluster. Therefore, the closest nonstandard electrode would have the subscript as 1, and each subscript would increase in numeric value as distance from the cardinal 10–10 electrode increases. Electrode position nomenclature which builds upon the international standard 10–10 system allows electroencephalographers to identify spatial areas of interest in hdEEG relative to positions in routine use. A standard viewing montage for hdEEG and its application with ESI both boosts efficiency when reviewing data, and also improves accuracy in recognizing epileptiform discharges. Furthermore, combining the montage with electrode geopositions will provide greater continuity and ease of use across analysis techniques that would potentially increase adoption of source analysis in clinical care. Our proposed system could also be expanded to higher numbers of electrodes or additional positions on the face or head and is not limited to a specific hdEEG system or electrode count.