The Influence of Age and Skull Conductivity on Surface and Subdermal Bipolar EEG Leads

Bioelectric source measurements are influenced by the measurement location as well as the conductive properties of the tissues. Volume conductor effects such as the poorly conducting bones or the moderately conducting skin are known to affect the measurement precision and accuracy of the surface electroencephalography (EEG) measurements. This paper investigates the influence of age via skull conductivity upon surface and subdermal bipolar EEG measurement sensitivity conducted on two realistic head models from the Visible Human Project. Subdermal electrodes (a.k.a. subcutaneous electrodes) are implanted on the skull beneath the skin, fat, and muscles. We studied the effect of age upon these two electrode types according to the scalp-to-skull conductivity ratios of 5, 8, 15, and 30 : 1. The effects on the measurement sensitivity were studied by means of the half-sensitivity volume (HSV) and the region of interest sensitivity ratio (ROISR). The results indicate that the subdermal implantation notably enhances the precision and accuracy of EEG measurements by a factor of eight compared to the scalp surface measurements. In summary, the evidence indicates that both surface and subdermal EEG measurements benefit better recordings in terms of precision and accuracy on younger patients

EEG/MEG Source Imaging: Methods, Challenges, and Open Issues

We present the four key areas of research—preprocessing, the volume conductor, the forward problem, and the inverse problem—that affect the performance of EEG and MEG source imaging. In each key area we identify prominent approaches and methodologies that have open issues warranting further investigation within the community, challenges associated with certain techniques, and algorithms necessitating clarification of their implications. More than providing definitive answers we aim to identify important open issues in the quest of source localization

Bioelectromagnetism : principles and applications of bioelectric and biomagnetic fields /

Includes bibliographical references and indexes

Innovative Teaching Practice and Assessment with Technology Applications in International Biomedical Engineering Education, Chapter 11

The advantages of the Internet in education are widely acknowledged by students and teachers all over the world. The authors have developed EVICAB as a free-access portal for e-learning with a full curriculum in biomedical engineering. It may be used as a virtual campus to support classroom lecturing or for distant learning. EVICAB provides educational material in various formats: video lectures to be viewed on a PC, an iPod or a media phone, lecture slides, textbook, exercises. It also offers a system for an Internet examination, which makes it possible for the students to take the examination anywhere in the world, where an educational institution provides proper environment. In this chapter, the authors briefly introduce the technology of the EVICAB portal and discuss in more detail the application of the Internet examination system. Educational technologies for developing teaching and learning via the Internet are widely available and user friendly