38 research outputs found
Quantitative analysis by renormalized entropy of invasive electroencephalograph recordings in focal epilepsy
Invasive electroencephalograph (EEG) recordings of ten patients suffering
from focal epilepsy were analyzed using the method of renormalized entropy.
Introduced as a complexity measure for the different regimes of a dynamical
system, the feature was tested here for its spatio-temporal behavior in
epileptic seizures. In all patients a decrease of renormalized entropy within
the ictal phase of seizure was found. Furthermore, the strength of this
decrease is monotonically related to the distance of the recording location to
the focus. The results suggest that the method of renormalized entropy is a
useful procedure for clinical applications like seizure detection and
localization of epileptic foci.Comment: 10 pages, 5 figure
Generalized recurrence plot analysis for spatial data
Recurrence plot based methods are highly efficient and widely accepted tools
for the investigation of time series or one-dimensional data. We present an
extension of the recurrence plots and their quantifications in order to study
recurrent structures in higher-dimensional spatial data. The capability of this
extension is illustrated on prototypical 2D models. Next, the tested and proved
approach is applied to assess the bone structure from CT images of human
proximal tibia. We find that the spatial structures in trabecular bone become
more self-similar during the bone loss in osteoporosis