Creating a Virtual Brain with a Supercomputer
Nonlinear EEG Analysis of Epilepsy Patients
Epilepsy manifests itself not only in visible seizures, but also
in characteristic patterns in the
electroencephalogram (EEG). It is thus an important field of application for modern methods of
nonlinear time series analysis. In collaboration with the Department of Epileptology at the
University of Bonn, we are pursuing two main aims. On the one hand, we develop methods for
localizing epileptic foci in patients who are possible candidates for surgery.
The figure shows regions
with elevated (green) and high (red) likelihood of being a focus in a
retrospective analysis. Also
shown is the region which has actually been removed, based on other analyses (black). In the
case illustrated, the primary focus had been correctly recognized and
removed, and the patient is
now free of seizures. An advantage of our method over previous ones is that it uses only data
from seizure-free epochs, and that their predictions do not always agree with those of other
methods. In some rare cases where the patient is not completely free of seizures, our analysis
would suggest that there is indeed a secondary focus or that the primary focus has not been
removed entirely.
A second - and much more ambitious - aim of our research is to predict seizures. Finally, our
work is also aimed at the development of new methods of nonlinear time series analysis which
will then be applied to other fields in interdisciplinary collaborations.
(Ralph Gregor Andrzejak, Thomas Kreuz, Alexander Kraskov,
Peter Grassberger, NIC Research Group "Complex Systems", Jülich;
Florian Mormann, Klaus Lehnertz, Christian E. Elger,
Department of Epileptology, University of Bonn; and Peter David,
Physics Department, University of Bonn)
Sabine Höfler-Thierfeldt