A Proposed Phonography-Based Measurement of Fetal Breathing Movement Using Segmented Structures with Frequency Splitting.

This paper proposes a detection method of fetal breathing movement (FBM) as an important data of fetal well-being. To analyze the chaotic nature of the individual episodes, the frequency band has been split into single test frequencies in order to find its starting point (SP) as a signal free (quiet) zone. Computing some features of the signal the sound will be distinguishable from the disturbing signals as hiccups, body's rotation and limb movements or even additional noises of maternal heart beats. The SPs of the episodes are characterized by an approximation process in order to select the real ones.Clinical relevance- The method is an irradiation free measurement, carried out on the maternal abdomen. Furthermore, connected with the fetal phonocardiographic (fPCG) monitoring the method offers a non-invasive way for FBM detection applicable also at home. More than 50 pregnancies were examined with the proposed method for at least for 20-min with synchronous measurements by the proposed phonographic device and a 3D ultrasound machine in the third trimester.

Computer method for perinatal screening of cardiac murmur using fetal phonocardiography.

The main purpose of this paper is to demonstrate the capability of fetal phonocardiographic measurements to indicate some congenital heart defects. It deals with the results of investigations carried out during the last four years involving 820 pregnant women. During the investigations fetal cardiac murmurs presenting typical waveforms and incidences of acoustic signals were recorded. Causes of these murmurs are suggested based on comparison with the well-known waveforms of infants and children. A sophisticated signal processing method for murmur discovery is presented, that is also useful for automatic perinatal screening after the 28th week of gestation. By these means low-risk population may also be fully tested for cardiac malfunctions.

Experiences with fetal phonocardiographic telemonitoring and future possibilities.

Phonocardiography (PCG) makes possible the examination of some fetal cardiac anomalies which otherwise usually remain undetected during pregnancy. The application of PCG in a telemonitoring system enhances its diagnostic capabilities, allowing long-term measurements even at home. The paper summarizes the intensive fetal monitoring campaign carried out in Hungary during the last three years that yielded useful experience regarding recent and future possibilities of fetal monitoring. Results collected from a large number of measurements suggest that PCG home monitoring may be a suitable screening method for fetal congenital heart diseases, even if surgical intervention in this phase of pregnancy is not easy.

Application of the matching pursuit method in a fetal phonocardiographic telemedicine system.

A novel compact method for fetal home monitoring optimized for long data acquisition time has already been presented. The method involves preprocessing a disturbed acoustic signal received on the maternal abdomen. The present work summarizes phenomena encountered during analysis of the incoming PCG signal, and describes further improvements made to the analysis system already in use including the application of the MP method to determining heartbeat lengths and identifying murmurs between heart sounds.

Fetal breathing transmission in phonocardiographic monitoring telemedicine systems.

The phonocardiographic monitoring of fetal heart activity due to its passive nature enables extremely long measuring times providing thus the possibility of fetal breathing recovery. The long monitoring time is required because of the temporary appearing of breathing movement. However, the long measurement time and consequently the large amount of data to be transmitted to the hospital's computer centre may be costly on mobile phone network. To keep monitoring costs low an appropriate data compression should be applied assuring the transmission of all important features of the detected acoustic signal. The present work summarizes the results of the extension of the novel telemedicine system with measurement of breathing periodicity and the achieved compression level of acquisited data. The Golomb-Rice compression is applied for lossless transmission of the segmented beat cycles considering the importance of the given segments in order to obtain the most accurate transfer of beat-to-beat time and all irregular heart sounds.

Long-term Phonocardiographic Fetal Home Monitoring for Telemedicine Systems.

A novel compact method for fetal home monitoring optimized for long data acquisition time and low communication costs is presented. The method incorporates the preprocessing of disturbed acoustic signal received on the maternal abdomen. The basic idea of the preprocessing is that the detection of the systolic and diastolic sounds takes place on two separated frequency bands with autocorrelation on predicted time intervals. Measurements on 47 selected pregnant women have shown that the use of this method significantly reduces the amount of data to be transferred to the computer centre in the hospital, where only the very disturbed time periods have to be evaluated. Based on this method a new, phonocardiographic fetal telemedicine system can be built without time limitation of measurements.