“…Since then ordinal symbolic analysis has remained a popular method in biology and medicine, especially when it comes to distinguishing abnormal from normal health conditions in real time. Specific examples include epilepsy [16][17][18][19][20][21][22][23][24], anaesthesia [25][26][27][28][29][30][31][32][33][34][35], cardiology [36][37][38][39][40][41], event-related potential (ERP) analysis [42,43], Alzheimer's disease [44], sleep research [45] and brain-computer interfaces [46]. For a review of biomedical (and econophysics) applications of permutation entropy, see also [47].…”