Multiscale entropy analysis of biological signals Author: Madalena Costa1, Ary L Goldberger, C-K Peng Affiliation: <sup>1</sup> Margret and H. A. Rey Institute for Nonlinear Dynamics in Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA. Conference/Journal: Phys Rev E Stat Nonlin Soft Matter Phys Date published: 2005 Feb 1 Other: Volume ID: 71 , Issue ID: 2 Pt 1 , Pages: 021906 , Special Notes: doi: 10.1103/PhysRevE.71.021906. , Word Count: 162 Traditional approaches to measuring the complexity of biological signals fail to account for the multiple time scales inherent in such time series. These algorithms have yielded contradictory findings when applied to real-world datasets obtained in health and disease states. We describe in detail the basis and implementation of the multiscale entropy (MSE) method. We extend and elaborate previous findings showing its applicability to the fluctuations of the human heartbeat under physiologic and pathologic conditions. The method consistently indicates a loss of complexity with aging, with an erratic cardiac arrhythmia (atrial fibrillation), and with a life-threatening syndrome (congestive heart failure). Further, these different conditions have distinct MSE curve profiles, suggesting diagnostic uses. The results support a general "complexity-loss" theory of aging and disease. We also apply the method to the analysis of coding and noncoding DNA sequences and find that the latter have higher multiscale entropy, consistent with the emerging view that so-called "junk DNA" sequences contain important biological information. PMID: 15783351 DOI: 10.1103/PhysRevE.71.021906