Connectivity analysis of multichannel EEG signals using recurrence based phase synchronization technique

• Published in: Computers in biology and medicine Vol. 46; no. C; pp. 11 - 21
• Main Author: Rangaprakash, D.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.03.2014; Elsevier Limited
• Subjects: Brain - physiopathology; Brain connectivity; Brain headmap; Chaos theory; Correlation between probabilities of recurrence; Dynamical systems; EEG signals; Electroencephalography; Electroencephalography Phase Synchronization; Epilepsy - diagnosis; Epilepsy - physiopathology; Epileptic seizure; Female; Humans; Internal Medicine; Linear correlation; Male; Methods; Models, Neurological; Other; Phase synchronization; Recurrence quantification analysis; Signal Processing, Computer-Assisted; Standard deviation; Studies; Linear correlation; Brain connectivity; Phase synchronization; EEG signals; Recurrence quantification analysis; Correlation between probabilities of recurrence; Epileptic seizure; Brain headmap
• ISSN: 0010-4825; 1879-0534; 1879-0534
• DOI: 10.1016/j.compbiomed.2013.10.025

Real world biological systems such as the human brain are inherently nonlinear and difficult to model. However, most of the previous studies have either employed linear models or parametric nonlinear models for investigating brain function. In this paper, a novel application of a nonlinear measure of phase synchronization based on recurrences, correlation between probabilities of recurrence (CPR), to study connectivity in the brain has been proposed. Being non-parametric, this method makes very few assumptions, making it suitable for investigating brain function in a data-driven way. CPR’s utility with application to multichannel electroencephalographic (EEG) signals has been demonstrated. Brain connectivity obtained using thresholded CPR matrix of multichannel EEG signals showed clear differences in the number and pattern of connections in brain connectivity between (a) epileptic seizure and pre-seizure and (b) eyes open and eyes closed states. Corresponding brain headmaps provide meaningful insights about synchronization in the brain in those states. K-means clustering of connectivity parameters of CPR and linear correlation obtained from global epileptic seizure and pre-seizure showed significantly larger cluster centroid distances for CPR as opposed to linear correlation, thereby demonstrating the superior ability of CPR for discriminating seizure from pre-seizure. The headmap in the case of focal epilepsy clearly enables us to identify the focus of the epilepsy which provides certain diagnostic value.