Table 6.

The nonlinear CVs of EBSs

Nonlinear CVs	Calculation methods	Physiological significance
RR	The percentage of recurrent points falling within the specified radius	Reflect the similarity of signal fluctuation
Lmean	The mean of the diagonal lengths in recurrence plot	Related to the separation velocity of adjacent trajectories
ENTR	The Shannon information entropy of all diagonal line lengths	A measure of signal complexity
TT	The average length of vertical line structures	Degree of system stability

CVs characteristic values, EBSs effective bowel sounds