Authors:
J. A. L. Marques
1
;
P. C. Cortez
2
;
J. P. V. Madeiro
2
and
F. S. Schlindwein
3
Affiliations:
1
University Lusiada of Angola, Angola
;
2
Federal University of Ceará, Brazil
;
3
University of Leicester, United Kingdom
Keyword(s):
Fetal Heart Rate, Sample Entropy, Nonlinear Analysis.
Related
Ontology
Subjects/Areas/Topics:
Applications and Services
;
Biomedical Engineering
;
Biomedical Signal Processing
;
Cardiovascular Signals
;
Computer Vision, Visualization and Computer Graphics
;
Medical Image Detection, Acquisition, Analysis and Processing
;
Physiological Processes and Bio-Signal Modeling, Non-Linear Dynamics
Abstract:
The complex system of mother and foetus interacting during pregnancy contains both dependent and independent subsystems and it is unlikely that it can be studied using only linear techniques. Considering this, the conventional medical analysis of Fetal Heart Rate (FHR) based on Cardiotocography (CTG) traces can be expanded considering nonlinear approaches. This work presents the use of Sample Entropy (SampEn) as a measure of system complexity, using a 5 minutes window of FHR signal (1200 samples), using values for parameters m and r based on literature to analyse the signal complexity behaviour in time. The database is comprised of 22 pre-classified intrapartum exams, expected to have a high degree of time domain dynamics. The analysis shows that severe FHR decelerations result in small values of SampEn, reflecting a low level of complexity. On the other hand, a set of high level transient FHR accelerations also causes the same effect. The occurrences of repetitive patterns (similar
to sinusoidal waves, which are pathological) cause a drop of SampEn values. The results encourage us to consider SampEn as one viable parameter for nonlinear FHR signal analysis.
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