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Sample records for ballistocardiography

  1. Nocturnal Sleep Quality and Quantity Analysis with Ballistocardiography

    OpenAIRE

    Nurmi, Sami

    2016-01-01

    The aim of this thesis was to evaluate usability and performance of a ballistocardiography (BCG) based method for qualitative and quantitative analysis of sleep. The method was validated and the basis for sleep stage detection was presented. Sleep problems are one of the most common medical complaints today. Polysomnography (PSG) as the current standard for sleep analysis is expensive, intrusive and complicated. Thus, finding a reliable and unobtrusive method for longer-term home use is...

  2. Applying Novel Time-Frequency Moments Singular Value Decomposition Method and Artificial Neural Networks for Ballistocardiography

    Directory of Open Access Journals (Sweden)

    Alpo Värri

    2007-01-01

    Full Text Available As we know, singular value decomposition (SVD is designed for computing singular values (SVs of a matrix. Then, if it is used for finding SVs of an m-by-1 or 1-by-m array with elements representing samples of a signal, it will return only one singular value that is not enough to express the whole signal. To overcome this problem, we designed a new kind of the feature extraction method which we call ‘‘time-frequency moments singular value decomposition (TFM-SVD.’’ In this new method, we use statistical features of time series as well as frequency series (Fourier transform of the signal. This information is then extracted into a certain matrix with a fixed structure and the SVs of that matrix are sought. This transform can be used as a preprocessing stage in pattern clustering methods. The results in using it indicate that the performance of a combined system including this transform and classifiers is comparable with the performance of using other feature extraction methods such as wavelet transforms. To evaluate TFM-SVD, we applied this new method and artificial neural networks (ANNs for ballistocardiogram (BCG data clustering to look for probable heart disease of six test subjects. BCG from the test subjects was recorded using a chair-like ballistocardiograph, developed in our project. This kind of device combined with automated recording and analysis would be suitable for use in many places, such as home, office, and so forth. The results show that the method has high performance and it is almost insensitive to BCG waveform latency or nonlinear disturbance.

  3. Applying Novel Time-Frequency Moments Singular Value Decomposition Method and Artificial Neural Networks for Ballistocardiography

    Directory of Open Access Journals (Sweden)

    Koivistoinen Teemu

    2007-01-01

    Full Text Available As we know, singular value decomposition (SVD is designed for computing singular values (SVs of a matrix. Then, if it is used for finding SVs of an -by-1 or 1-by- array with elements representing samples of a signal, it will return only one singular value that is not enough to express the whole signal. To overcome this problem, we designed a new kind of the feature extraction method which we call ''time-frequency moments singular value decomposition (TFM-SVD.'' In this new method, we use statistical features of time series as well as frequency series (Fourier transform of the signal. This information is then extracted into a certain matrix with a fixed structure and the SVs of that matrix are sought. This transform can be used as a preprocessing stage in pattern clustering methods. The results in using it indicate that the performance of a combined system including this transform and classifiers is comparable with the performance of using other feature extraction methods such as wavelet transforms. To evaluate TFM-SVD, we applied this new method and artificial neural networks (ANNs for ballistocardiogram (BCG data clustering to look for probable heart disease of six test subjects. BCG from the test subjects was recorded using a chair-like ballistocardiograph, developed in our project. This kind of device combined with automated recording and analysis would be suitable for use in many places, such as home, office, and so forth. The results show that the method has high performance and it is almost insensitive to BCG waveform latency or nonlinear disturbance.

  4. Applying Novel Time-Frequency Moments Singular Value Decomposition Method and Artificial Neural Networks for Ballistocardiography

    Science.gov (United States)

    Akhbardeh, Alireza; Junnila, Sakari; Koivuluoma, Mikko; Koivistoinen, Teemu; Värri, Alpo

    2006-12-01

    As we know, singular value decomposition (SVD) is designed for computing singular values (SVs) of a matrix. Then, if it is used for finding SVs of an [InlineEquation not available: see fulltext.]-by-1 or 1-by- [InlineEquation not available: see fulltext.] array with elements representing samples of a signal, it will return only one singular value that is not enough to express the whole signal. To overcome this problem, we designed a new kind of the feature extraction method which we call ''time-frequency moments singular value decomposition (TFM-SVD).'' In this new method, we use statistical features of time series as well as frequency series (Fourier transform of the signal). This information is then extracted into a certain matrix with a fixed structure and the SVs of that matrix are sought. This transform can be used as a preprocessing stage in pattern clustering methods. The results in using it indicate that the performance of a combined system including this transform and classifiers is comparable with the performance of using other feature extraction methods such as wavelet transforms. To evaluate TFM-SVD, we applied this new method and artificial neural networks (ANNs) for ballistocardiogram (BCG) data clustering to look for probable heart disease of six test subjects. BCG from the test subjects was recorded using a chair-like ballistocardiograph, developed in our project. This kind of device combined with automated recording and analysis would be suitable for use in many places, such as home, office, and so forth. The results show that the method has high performance and it is almost insensitive to BCG waveform latency or nonlinear disturbance.

  5. Identifying sleep apnea syndrome using heart rate and breathing effort variation analysis based on ballistocardiography.

    Science.gov (United States)

    Weichao Zhao; Hongbo Ni; Xingshe Zhou; Yalong Song; Tianben Wang

    2015-08-01

    Sleep apnea syndrome (SAS) is regarded as one of the most common sleep-related breathing disorders, which can severely affect sleep quality. Since SAS is usually accompanied with the cyclical heart rate variation (HRV), many studies have been conducted on heart rate (HR) to identify it at an earlier stage. While most related work mainly based on clinical devices or signals (e.g., polysomnography (PSG), electrocardiography (ECG)), in this paper we focus on the ballistocardiographic (BCG) signal which is obtained in a non-invasive way. Moreover, as the precision and reliability of BCG signal are not so good as PSG or ECG, we propose a fine-grained feature extraction and analysis approach in SAS recognition. Our analysis takes both the basic HRV features and the breathing effort variation into consideration during different sleep stages rather than the whole night. The breathing effort refers to the mechanical interaction between respiration and BCG signal when SAS events occur, which is independent from autonomous nervous system (ANS) modulations. Specifically, a novel method named STC-Min is presented to extract the breathing effort variation feature. The basic HRV features depict the ANS modulations on HR and Sample Entropy and Detrended Fluctuation Analysis are applied for the evaluations. All the extracted features along with personal factors are fed into the knowledge-based support vector machine (KSVM) classification model, and the prior knowledge is based on dataset distribution and domain knowledge. Experimental results on 42 subjects in 3 nights validate the effectiveness of the methods and features in identifying SAS (90.46% precision rate and 88.89% recall rate). PMID:26737303

  6. A simple ballistocardiographic system for a medical cardiovascular physiology course.

    Science.gov (United States)

    Eblen-Zajjur, Antonio

    2003-12-01

    Ballistocardiography is an old, noninvasive technique used to record the movements of the body synchronous with the heartbeat due to left ventricular pump activity. Despite the fact that this technique to measure cardiac output has been superseded by more advanced and precise techniques, it is useful for teaching cardiac cycle physiology in an undergraduate practical course because of its noninvasive application in humans, clear physiological and physiopathological analysis, and practical approach to considering cardiac output issues. In the present report, a simple, low cost, easy-to-build ballistocardiography system is implemented together with a theoretical and practical session that includes Newton's laws, cardiac output, cardiac pump activity, anatomy and physiology of the vessel circulation, vectorial composition, and signal transduction, which makes cardiovascular physiology easy to understand and focuses on the study of cardiac output otherwise seen only with the help of computer simulation or echocardiography. The proposed system is able to record body displacement or force as ballistocardiography traces and its changes caused by different physiological factors. The ballistocardiography session was included in our medical physiology course six years ago with very high acceptance and approval rates from the students.

  7. A NOVEL BCG SENSOR-ARRAY FOR UNOBTRUSIVE CARDIAC MONITORING

    OpenAIRE

    Anna Böhm; Christoph Brüser; Steffen Leonhardt Leonhardt

    2013-01-01

    Unobtrusive heart rate monitoring is a popular research topic in biomedical engineering. The reason is that convential methods, e.g. the clinical gold standard electrocardiography, require conductive contact to the human body. Other methods such as ballistocardiography try to record these vital signs without electrodes that are attached to the body. So far, these systems cannot replace routine procedures. Most systems have some drawbacks that cannot be compensated, such as aging of the sensor...

  8. [Stress-protective properties of lithium nicotinate--a new derivative of nicotinic acid].

    Science.gov (United States)

    Kresiun, V I

    1984-03-01

    Experiments were made to study stress-protective properties of a new psychotropic agent lithium nicotinate developed on the basis of natural metabolites. Prophylactic treatment of the drug given in courses entails an increase in the physical endurance and work fitness, improvement of animals' orientation under stress, facilitating the avoidance behavior. These effects were particularly demonstrable in highly emotional animals. In these animals, stress produced a paralyzing action. According to the electro- and ballisto-cardiography, the drug prevented the stress-induced disorders of cardiovascular function. PMID:6538449

  9. Capacitive detection of micromotions: Monitoring ballistics of a developing avian embryo

    Science.gov (United States)

    Szymanski, Jan A.; Pawlak, Krzysztof; Wasowicz, Pawel; Moscicki, Jozef K.

    2002-09-01

    An instrument for noninvasive monitoring of very weak biomechanical activities of small living organisms is described. The construction is sufficiently flexible to permit a range of studies including developing embryos of oviparous animals, pests that live in loose materials and timber, and insects that develop in cocoons. Motions are detected by monitoring a current generated by the fluctuating position of the object-loaded electrode of a capacitive sensor. To maximize the signal, oscillations of the electrode are mechanically enhanced and the current is amplified and filtered by a two-stage signal amplifier and a bank of six active Butterworth filters. The device is optimized to ballistocardiography of hen embryos. The sensitivity achieved makes possible quantitative studies of heart activity of 7-day-old embryos.

  10. Ballistocardiogram: Mechanism and Potential for Unobtrusive Cardiovascular Health Monitoring.

    Science.gov (United States)

    Kim, Chang-Sei; Ober, Stephanie L; McMurtry, M Sean; Finegan, Barry A; Inan, Omer T; Mukkamala, Ramakrishna; Hahn, Jin-Oh

    2016-01-01

    For more than a century, it has been known that the body recoils each time the heart ejects blood into the arteries. These subtle cardiogenic body movements have been measured with increasingly convenient ballistocardiography (BCG) instruments over the years. A typical BCG measurement shows several waves, most notably the "I", "J", and "K" waves. However, the mechanism for the genesis of these waves has remained elusive. We formulated a simple mathematical model of the BCG waveform. We showed that the model could predict the BCG waves as well as physiologic timings and amplitudes of the major waves. The validated model reveals that the principal mechanism for the genesis of the BCG waves is blood pressure gradients in the ascending and descending aorta. This new mechanistic insight may be exploited to allow BCG to realize its potential for unobtrusive monitoring and diagnosis of cardiovascular health and disease. PMID:27503664

  11. Unobtrusive Non-Contact Detection of Arrhythmias using a “Smart” Bed

    Directory of Open Access Journals (Sweden)

    Ch. Brueser

    2011-01-01

    Full Text Available We present an instrumented bed for unobtrusive, non-contact monitoring of cardiac and respiratory activity. The system presented here is based on the principle of ballistocardiography (BCG, and measures cardiopulmonary vibrations of the body by means of an electromechanical foil (EMFi attached to the mattress. Using our system, a clinical study with 13 participants was conducted to assess the BCG’s ability to distinguish atrial fibrillations from normal sinus rhythms. By computing a time-frequency representation of the recorded signals based on parametric autoregressive estimators, we can show clear qualitative differences between normal and arrhythmic BCG episodes. The same distinctive features could also be observed when applying our method to a simultaneously recorded reference ECG. Our results suggest that ECG and BCG both contain the same basic information with respect to the presence of atrial fibrillations, and that a bed-mounted BCG sensor can indeed be used to detect atrial fibrillations.

  12. A low-noise ac-bridge amplifier for ballistocardiogram measurement on an electronic weighing scale

    International Nuclear Information System (INIS)

    Ballistocardiography is a non-invasive technique for evaluating cardiovascular health. This note presents an ac-bridge amplifier for low-noise ballistocardiogram (BCG) recording from a modified weighing scale. The strain gauges in a commercial scale were excited by an ac source—square or sine wave—and the differential output voltage resulting from the BCG was amplified and demodulated synchronously with the excitation waveform. A standard BCG amplifier, with a simple dc-bridge excitation, was also built and the performance was compared to both the square- and sine-wave excited ac-bridge amplifiers. The total input-referred voltage noise (rms) integrated over the relevant BCG bandwidth of 0.3–10 Hz was found to be 30 nV (square wave source) or 25 nV (sine-wave source) for the ac-bridge amplifier and 52 nV for the standard amplifier: an improvement of 4.8 dB or 6 dB, respectively. These correspond to input-referred force noise (rms) values of 5 mN, 4 mN and 8.3 mN. The improvement in SNR was also observed in recorded waveforms from a seated subject whose BCG signal was measured with both dc- and ac-bridge circuits. (note)

  13. The Application of a Piezo-Resistive Cardiorespiratory Sensor System in an Automobile Safety Belt

    Directory of Open Access Journals (Sweden)

    Syed Talha Ali Hamdani

    2015-03-01

    Full Text Available Respiratory and heart failure are conditions that can occur with little warning and may also be difficult to predict. Therefore continuous monitoring of these bio-signals is advantageous for ensuring human health. The car safety belt is mainly designed to secure the occupants of the vehicle in the event of an accident. In the current research a prototype safety belt is developed, which is used to acquire respiratory and heart signals, under laboratory conditions. The current safety belt is constructed using a copper ink based nonwoven material, which works based on the piezo-resistive effect due to the pressure exerted on the sensor as a result of expansion of the thorax/abdomen area of the body for respiration and due to the principle of ballistocardiography (BCG in heart signal sensing. In this research, the development of a theoretical model to qualitatively describe the piezo-resistive material is also presented in order to predict the relative change in the resistance of the piezo-resistive material due to the pressure applied.

  14. Heartbeat Cycle Length Detection by a Ballistocardiographic Sensor in Atrial Fibrillation and Sinus Rhythm

    Directory of Open Access Journals (Sweden)

    Matthias Daniel Zink

    2015-01-01

    Full Text Available Background. Heart rate monitoring is especially interesting in patients with atrial fibrillation (AF and is routinely performed by ECG. A ballistocardiography (BCG foil is an unobtrusive sensor for mechanical vibrations. We tested the correlation of heartbeat cycle length detection by a novel algorithm for a BCG foil to an ECG in AF and sinus rhythm (SR. Methods. In 22 patients we obtained BCG and synchronized ECG recordings before and after cardioversion and examined the correlation between heartbeat characteristics. Results. We analyzed a total of 4317 heartbeats during AF and 2445 during SR with a correlation between ECG and BCG during AF of r=0.70 (95% CI 0.68–0.71, P<0.0001 and r=0.75 (95% CI 0.73–0.77, P<0.0001 during SR. By adding a quality index, artifacts could be reduced and the correlation increased for AF to 0.76 (95% CI 0.74–0.77, P<0.0001, n=3468 and for SR to 0.85 (95% CI 0.83–0.86, P<0.0001, n=2176. Conclusion. Heartbeat cycle length measurement by our novel algorithm for BCG foil is feasible during SR and AF, offering new possibilities of unobtrusive heart rate monitoring. This trial is registered with IRB registration number EK205/11. This trial is registered with clinical trials registration number NCT01779674.

  15. The application of a piezo-resistive cardiorespiratory sensor system in an automobile safety belt.

    Science.gov (United States)

    Hamdani, Syed Talha Ali; Fernando, Anura

    2015-03-30

    Respiratory and heart failure are conditions that can occur with little warning and may also be difficult to predict. Therefore continuous monitoring of these bio-signals is advantageous for ensuring human health. The car safety belt is mainly designed to secure the occupants of the vehicle in the event of an accident. In the current research a prototype safety belt is developed, which is used to acquire respiratory and heart signals, under laboratory conditions. The current safety belt is constructed using a copper ink based nonwoven material, which works based on the piezo-resistive effect due to the pressure exerted on the sensor as a result of expansion of the thorax/abdomen area of the body for respiration and due to the principle of ballistocardiography (BCG) in heart signal sensing. In this research, the development of a theoretical model to qualitatively describe the piezo-resistive material is also presented in order to predict the relative change in the resistance of the piezo-resistive material due to the pressure applied.

  16. A NOVEL BCG SENSOR-ARRAY FOR UNOBTRUSIVE CARDIAC MONITORING

    Directory of Open Access Journals (Sweden)

    Anna Böhm

    2013-12-01

    Full Text Available Unobtrusive heart rate monitoring is a popular research topic in biomedical engineering. The reason is that convential methods, e.g. the clinical gold standard electrocardiography, require conductive contact to the human body. Other methods such as ballistocardiography try to record these vital signs without electrodes that are attached to the body. So far, these systems cannot replace routine procedures. Most systems have some drawbacks that cannot be compensated, such as aging of the sensor materials or movement artifacts. In addition, the signal form differs greatly from an ECG, which is an electrical signal. The ballistocardiogram has a mechanical source, which makes it harder to evaluate. We have developed a new sensor array made of near-IR-LEDs to record BCGs. IR-sensors do not age in relevant time scales. Analog filtering was neccesary, because the signal amplitude was very small. The digitized data was then processed by various algorithms to extract beat-to-beat or breath-to-breath intervals. The redundancy of multiple BCG channels was used to provide a robust estimation of beat-to-beat intervals and heart rate. We installed the system beneath a mattress topper of a hospital bed, but any other bed would have been sufficient. The validation of this measurement system shows that it is well suited for BCG recordings. The use of multiple channels has proven to be superior to relying on a single BCG channel.

  17. Detecting Aortic Valve Opening and Closing from Distal Body Vibrations

    CERN Document Server

    Wiens, Andrew D; Inan, Omer T

    2016-01-01

    Objective: Proximal and whole-body vibrations are well studied in seismocardiography and ballistocardiography, yet distal vibrations are still poorly understood. In this paper we develop two methods to measure aortic valve opening (AVO) and closing (AVC) from distal vibrations. Methods: AVO and AVC were detected for each heartbeat with accelerometers on the upper arm (A), wrist (W), and knee (K) of 22 consenting adults following isometric exercise. Exercise-induced changes were recorded with impedance cardiography, and nine-beat ensemble averaging was applied. Our first method, FilterBCG, detects peaks in distal vibrations after filtering with individually-tuned bandpass filters while RidgeBCG uses ridge regression to estimate AVO and AVC without peaks. Pseudocode is provided. Results: In agreement with recent studies, we did not find peaks at AVO and AVC in distal vibrations, and the conventional R-J interval method from the literature also correlated poorly with AVO (r2 = 0.22 A, 0.14 W, 0.12 K). Interestin...