B. Erem, R.M. Orellana, D.E. Hyde, J.M. Peters, F.H. Duffy, P. Stovicek, S.K. Warfield, R.S. MacLeod, G. Tadmor, D.H. Brooks. Extensions to a manifold learning framework for time-series analysis on dynamic manifolds in bioelectric signals, In Physical Review E, Vol. 93, No. 4, American Physical Society, apr, 2016.
This paper addresses the challenge of extracting meaningful information from measured bioelectric signals generated by complex, large scale physiological systems such as the brain or the heart. We focus on a combination of the well-known Laplacian eigenmaps machine learning approach with dynamical systems ideas to analyze emergent dynamic behaviors. The method reconstructs the abstract dynamical system phase-space geometry of the embedded measurements and tracks changes in physiological conditions or activities through changes in that geometry. It is geared to extract information from the joint behavior of time traces obtained from large sensor arrays, such as those used in multiple-electrode ECG and EEG, and explore the geometrical structure of the low dimensional embedding of moving time windows of those joint snapshots. Our main contribution is a method for mapping vectors from the phase space to the data domain. We present cases to evaluate the methods, including a synthetic example using the chaotic Lorenz system, several sets of cardiac measurements from both canine and human hearts, and measurements from a human brain.
B. Erem, J. Coll-Font, R.M. Orellana, P. Stovicek, D.H. Brooks. Using transmural regularization and dynamic modeling for noninvasive cardiac potential imaging of endocardial pacing with imprecise thoracic geometry, In IEEE Trans Med Imaging, Vol. 33, No. 3, pp. 726--738. 2014.
PubMed ID: 24595345
PubMed Central ID: PMC3950945
B. Erem, J. Coll-Font, R.M. Orellana, P. Stovicek, D.H. Brooks, R.S. MacLeod. Noninvasive reconstruction of potentials on endocardial surface from body surface potentials and CT imaging of partial torso, In Journal of Electrocardiology, Vol. 46, No. 4, pp. e28. 2013.
B. Erem, R.M. Orellana, P. Stovicek, D.H. Brooks, R.S. MacLeod. Improved averaging of multi-lead ECGs and electrograms, In Journal of Electrocardiology, Vol. 46, No. 4, Elsevier, pp. e28. July, 2013.
B. Erem, P. Stovicek, D.H. Brooks. Manifold learning for analysis of low-order nonlinear dynamics in high-dimensional electrocardiographic signals, In Proceedings of the 9th IEEE International Symposium on Biomedical Imaging (ISBI), pp. 844--847. 2012.