Multiscale entropy analysis by APOE ε4 genotype.

<p>Multiscale entropy was derived from two-hours of interbeat interval time series. Symbols represent mean values of entropy for each group and the bars represent the standard error. Parameters of sample entropy calculation are m = 2 and r = 0.15. The sample entropy values for subjects with APOE ε4 allele are significantly lower (<i>p</i><0.01) on scales between 3 and 13, which are equal to oscillations at period around 10 to 40 heartbeats. <i>p</i> values were computed using Student's <i>t</i>-test at each scale factor.