A calculation method for uterine contraction coordination based on multi-channel electrohysterogram signals

Abstract

A method for calculating the coordination of uterine contractions based on multi-channel uterine electromyogram signals, comprising: Step 1: Collect multi-channel uterine electromyogram signals and TOCO signals for a certain period of time; Step 2: Mark the uterine contraction segments, and use a unified standard to define the starting point and ending point of uterine contractions. And divide all uterine contraction segments into labor-phase uterine contraction segments and gestational-phase uterine contraction segments; Step 3: Preprocess the uterine electromyogram signals; Step 4: Use the marked uterine contraction segments to segment the uterine electromyogram signals to obtain uterine electromyogram signals with only uterine contraction segments; Step 5: Calculate the inter-channel characteristics of all uterine contraction segments of the uterine electromyogram signals to reflect the consistency between EHG channels, so as to evaluate the coordination during the evolution of uterine contractions; Step 6: Use the Wilcoxon rank sum test to analyze the statistical differences of the selected characteristics in the two cases of the labor phase and the gestational phase.

Description

Technical Field

[0001] The present invention belongs to the technical field of bioelectrical signal analysis, and particularly relates to a multi-channel based method for characterizing uterine contraction coordination. Background Art

[0002] The perinatal mortality rate is an important indicator for evaluating social and economic development and health status, and is the main indicator for measuring the development level of perinatal medicine. Therefore, it is very necessary to monitor physiological activities during pregnancy and childbirth. Uterine contraction (hereinafter referred to as "uterine contraction") is the main driving force for a pregnant woman to give birth, and regular and coordinated uterine contractions are important indicators for judging the onset of labor in a pregnant woman. Uterine contractions are characterized by low amplitude and poor synchrony in the early stage, and as the delivery period approaches, the amplitude of uterine contractions will increase and become more synchronous.

[0003] Currently, the methods for monitoring uterine contraction coordination mainly combine the palpation method and the external parturition force meter method (tocodynamometry, TOCO). Doctors place their hands on the abdominal wall of the parturient and refer to the uterine contraction curve recorded by TOCO to judge the uterine contraction situation. However, this method is limited by the doctor's tactile sensitivity and the inaccuracy of TOCO signals.

[0004] The electrohysterogram (EHG) method is a non-invasive method for monitoring uterine contraction activities by collecting EHG signals from the abdomen of a pregnant woman. The EHG method can use multiple electrodes to collect EHG signals at different positions on the uterine wall, enriching the information between channels, and can be used to evaluate the evolution process of uterine contractions from local to synchronous throughout pregnancy. With the development of EHG research in recent years, uterine contraction monitoring based on EHG signals has good application prospects. Summary of the Invention

[0005] The present invention aims to overcome the above-mentioned drawbacks of the prior art and proposes a method for calculating uterine contraction coordination based on multi-channel EHG signals to replace the traditional manual judgment method.

[0006] The present invention proposes a method for calculating uterine contraction coordination based on the correlation between EHG signals of different channels, which can better assist medical diagnosis.

[0007] A method for calculating uterine contraction coordination based on multi-channel EHG signals for solving its technical problems is as follows:

[0008] Step 1: Collect multi-channel EHG signals and TOCO signals for a certain period of time;

[0009] Step 2: Mark the uterine contraction segments with the help of TOCO signals, and use a unified standard to define the starting point and ending point of uterine contractions. All uterine contraction segments are divided into delivery-period uterine contraction segments and pregnancy-period uterine contraction segments according to the recording time;

[0010] Step 3: Preprocess the uterine electromyogram signals.

[0011] Step 4: Segment the uterine electromyogram signals using the marked uterine contraction segments to obtain uterine electromyogram signals with only uterine contraction segments. The uterine electromyogram signals referred to hereinafter are all the segmented data.

[0012] Step 5: Calculate the inter-channel features of all uterine contraction segments of the uterine electromyogram signals. Calculate the correlation coefficient between any two channels of the uterine contraction segments and the sample entropy of all channels respectively to reflect the consistency among multiple EHG channels, so as to evaluate the coordination during the evolution of uterine contractions.

[0013] Step 6: Compare the correlation coefficients and multi-channel sample entropies of the uterine contraction segments in the delivery period and the pregnancy period, and use the Wilcoxon rank sum test to analyze the statistical differences of the selected features in the two cases of the delivery period and the pregnancy period.

[0014] The present invention provides a method for calculating the coordination of uterine contractions based on multi-channel uterine electromyogram signals. By using the uterine electromyogram signals of multiple channels, the electrical signals that trigger uterine contractions at different positions on the uterine wall can be collected. Calculating the correlation coefficient between any two channels of the uterine contraction segments and the sample entropy of all channels through the uterine electromyogram signals can reflect the consistency of uterine contractions among multiple channels, so as to evaluate the gradually coordinated evolution process of uterine contractions throughout the pregnancy.

[0015] The advantages of the present invention are as follows: The electrodes placed at different positions on the uterine wall can record the activity states of different muscle groups during uterine contractions, enriching the information volume. Using the inter-channel correlation coefficient and multi-channel sample entropy can reflect whether the electrical activities on different channels are consistent during uterine contractions, enabling the utilization of information between different channels, thereby better characterizing the coordination of uterine contractions. Description of the Drawings

[0016] Figure 1 is the flowchart of the method of the present invention

[0017] Figure 2 is the uterine electromyogram signal after preprocessing of the present invention

[0018] Figure 3 is the comparison of the consistency correlation coefficients in the delivery period and the pregnancy period of the present invention

[0019] Figure 4 is the comparison of the multi-channel sample entropies in the delivery period and the pregnancy period of the present invention Detailed Embodiment

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0022] The technical solutions of the present invention will be described in detail below.

[0023] A method for calculating the coordination of uterine contractions based on multi-channel uterine electromyogram signals includes the following steps:

[0024] Step 1: Collect multi-channel uterine electromyogram signals and TOCO signals for a certain period of time;

[0025] Step 2: Mark the uterine contraction segments with the help of the TOCO signal, and use a unified standard to define the starting point and ending point of uterine contractions. Divide all uterine contraction segments into intrapartum uterine contraction segments and gestational uterine contraction segments according to the recording time, and the results are shown in Table 1;

[0026] Table 1

[0027]

[0028] Step 3: Preprocess the uterine electromyogram signals;

[0029] Step 4: Segment the uterine electromyogram signals using the marked uterine contraction segments to obtain uterine electromyogram signals with only uterine contraction segments. The uterine electromyogram signals referred to later are all the segmented data;

[0030] Step 5: Calculate the inter-channel characteristics of all uterine contraction segments of the uterine electromyogram signals, and calculate the correlation coefficient between any two channels of the uterine contraction segments and the sample entropy of all channels respectively to reflect the consistency between multiple EHG channels, so as to evaluate the coordination during the evolution of uterine contractions;

[0031] Step 6: Compare the correlation coefficients and multi-channel sample entropies of intrapartum and gestational uterine contraction segments, and use the Wilcoxon rank sum test to analyze the statistical differences of the selected characteristics in the intrapartum and gestational periods.

[0032] The method for marking the uterine contraction segments in the above Step 2 is described in detail as follows:

[0033] Step 2.1: Use the TOCO signal to unify the criteria for marking the contraction segments. The specific criteria are as follows:

[0034] ● A significant increase in abdominal pressure (characterized by the TOCO signal);

[0035] ● The contraction burst should have a rough Gaussian shape;

[0036] ● The duration is between 10 - 120 seconds;

[0037] ● Consider regularity as an important hint.

[0038] Step 2.2: Divide the data according to the recording time of the maternal electromyogram signal. When the difference between the recording time and the delivery time of the pregnant woman is less than or equal to 24 hours, it is the contraction segment during the delivery period. When the difference between the recording time and the delivery time of the pregnant woman is greater than 24 hours, it is the contraction segment during the pregnancy period.

[0039] The method for preprocessing the maternal electromyogram signal in Step 3 above is described in detail as follows:

[0040] Step 3.1: Design a band - pass filter with a frequency band range (f 1 , f 2 ) to suppress the main noise components caused by respiration, motion artifacts, and maternal electrocardiogram;

[0041] Step 3.2: Downsample the data.

[0042] The method for calculating the correlation coefficient and multi - channel sample entropy in Step 5 above is described in detail as follows:

[0043] Step 5.1: Use Formula 1 to calculate the concordance correlation coefficient (CCC) of the electromyogram signals between any two channels. The higher the correlation coefficient, the higher the correlation and the stronger the synchronization between the two channels.

[0044]

[0045] Where X = {x 1 , x 2 , …, x N} and Y = {y 1 , y 2 , …, y N} respectively represent the data sequences of the zero - crossing rate curves of two different channels, and are the means of X and Y respectively, and are the variances of X and Y respectively, and S xy is the covariance of X and Y.

[0046] Step 5.2: Calculate the multi-channel sample entropy of the uterine electromyogram signals between all channels using Formulas 2 and 3.

[0047]

[0048] Where L represents the length of the uterine electromyogram signal after segmentation, c represents the number of channels of the uterine electromyogram signal, m represents the set vector dimension, represents the probability that two sequences match m points under the similarity tolerance r.

[0049]

[0050] The multi-channel sample entropy measures the complexity of the time series by measuring the probability of generating new patterns in the signal. The greater the probability of generating new patterns, the greater the complexity of the sequence. The lower the value of the multi-channel sample entropy, the higher the self-similarity of the sequence; the greater the value of the multi-channel sample entropy, the more complex the sample sequence.

[0051] The significance analysis method in Step 6 above is described in detail as follows:

[0052] Step 6.1: To better compare the statistical differences in the correlation coefficients and multi-channel sample entropies of the uterine electromyogram signals during the entire pregnancy contraction evolution process, the Wilcoxon rank sum test is used to conduct a statistical difference significance analysis test on the correlation coefficients and multi-channel sample entropies of the uterine electromyogram signals during the delivery period and the pregnancy period, and the results are shown in Table 2.

[0053] Table 2

[0054] Method Coefficient of consistency Multichannel sample entropy p-value 1.60e-14 2.05e-17

[0055] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0056] The above-described embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for calculating the coordination of uterine contractions based on multi-channel electrohysterogram (EHG) signals, comprising the following steps: Step 1: Collect multi-channel EHG signals and TOCO signals for a certain period of time; Step 2: Mark the uterine contraction segments with the help of TOCO signals, and use a unified standard to define the starting and ending points of uterine contractions; divide all uterine contraction segments into labor-phase uterine contraction segments and pregnancy-phase uterine contraction segments according to the recording time; Step 3: Preprocess the EHG signals; Step 4: Segment the EHG signals using the marked uterine contraction segments to obtain EHG signals with only uterine contraction segments. The EHG signals referred to hereinafter are all the segmented data; Step 5: Calculate the inter-channel features of all uterine contraction segments of the EHG signals, and calculate the correlation coefficient between any two channels of the uterine contraction segments and the sample entropy of all channels respectively to reflect the consistency between multiple EHG channels, so as to evaluate the coordination during the evolution of uterine contractions; specifically including: Step 5.1: Use formula (1) to calculate the concordance correlation coefficient (CCC) of the EHG signals between any two channels; where \(X = \{x 1 , x 2 , \cdots, x N \}\) and \(Y=\{y 1 , y 2 , \cdots, y N \}\) represent the data sequences of the zero-crossing rate curves of two different channels respectively, and are the means of \(X\) and \(Y\) respectively, and are the variances of \(X\) and \(Y\) respectively, and \(S xy is the covariance of \(X\) and \(Y\); Step 5.2: Use formula (2) and formula (3) to calculate the multi-channel sample entropy of the EHG signals between all channels; where L represents the length of the myoelectrical signal of the uterus after segmentation, c represents the number of channels of the myoelectrical signal of the uterus, and m represents the set vector dimension, represents the probability that two sequences match m points under the similarity tolerance r; Step 6: Compare the correlation coefficients and multi-channel sample entropies of the uterine contraction segments in the labor phase and the pregnancy phase, and use the Wilcoxon rank-sum test to analyze the statistical differences of the selected features in the two cases of the labor phase and the pregnancy phase.

2. A method for calculating the coordination of uterine contractions based on multi-channel EHG signals according to claim 1, characterized in that: The method for marking the uterine contraction segments in Step 2 is described in detail as follows: Step 2.1: Use the TOCO signal to unify the standard for marking uterine contraction segments. The specific standard is as follows: ● A significant increase in abdominal pressure characterized by the TOCO signal; ● The uterine contraction onset has a rough Gaussian shape; ● The duration is between 10 and 120 seconds; ● Regularity is used as an important cue; Step 2.2: Divide the data according to the recording time of the pregnant woman's EHG signals. When the difference between the recording time and the delivery time of the pregnant woman is less than or equal to 24 hours, it is a labor-phase uterine contraction segment; when the difference between the recording time and the delivery time of the pregnant woman is greater than 24 hours, it is a pregnancy-phase uterine contraction segment.

3. A method for calculating the coordination of uterine contractions based on multi-channel EHG signals according to claim 1, characterized in that: The method for preprocessing the EHG signals is described in detail as follows: Step 3.1: Design a band-pass filter to suppress the main noise components caused by respiration, motion artifacts, and maternal electrocardiogram; Step 3.2: Downsample the data.

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