Abstract: A device and a method of sensing and transmitting physiological pressures and body temperatures are disclosed. The device includes a transducer and a transmitter. The transmitter is adapted to broadcast a signal which is modulated by the output of a transducer. The transmitter is also adapted to limit the power of the output signal. The method includes transducing a physiological parameter and broadcasting a signal which is modulated by the transduced parameter. The power of the output signal is limited so that the signal will attenuate within a predetermined distance.

Abstract: A heart-sound detecting apparatus, including: a heart-sound microphone which detects a plurality of heart sounds produced by a heart of a living subject and outputs a heart-sound signal representative of the detected heart sounds; a smoothing device for smoothing, by differentiation, a waveform of the heart-sound signal output from the heart-sound microphone; a squaring device for squaring an amplitude of the smoothed waveform with respect to a base line of the heart-sound signal; and a start-point determining device for determining a start point of a first heart sound I as one of the detected heart sounds, based on that the squared amplitude is greater than a prescribed threshold value.

Abstract: This invention concerns a method and system for automatically determining heart rate. The invention can be applied to determining the heart of any animal including humans. The method involves sensing body sounds and transducing them to electrical signals. Digitizing the electrical signals. Emphasizing the heart sound maxima (S1 and S2 signals) relative to noise by filtering, decompression and squaring. Detecting local maxima in the signals as likely S1 signals and generating a threshold amplitude. Selecting maxima that exceed the threshold as surviving likely candidate S1 signals. Screening the surviving candidate S1 against physiologically derived criteria. And, calculating the heart rate from the screened S1.

Abstract: A method and system for automatically detecting heart sounds. The sound system receives sound data corresponding to beats of the heart. The sound system analyzes the sound data to detect the presence of a heart sound within the beats. The sound system then outputs an indication of the heart sounds that were detected. The sound system may use ECG data to identify various locations (e.g., R peak) within a beat and use those locations to assist in the detection of heart sounds.

Abstract: A method and system for analyzing sounds originating in at least a portion of an individual's cardiovascular system. N transducers, where N is an integer, are fixed on a surface of the individual over the thorax. The ith transducer is fixed at a location xi and generates an initial signal P(xi,i) indicative of pressure waves at the location xi, for i=1 to N. the signals P(xi,t) are processed so as to generate filtered signals in which at least one component of the signals P(xi,t)not arising from cardiovascular sounds has been removed. The filtered signals may be used for generating an image of the at least portion of the cardiovascular system.

Abstract: The present invention provides systems and methods for performing automated auscultation and diagnosis of conditions of the cardiovascular system. The invention acquires an acoustic signal emanating from the cardiovascular system via an sensor. In addition, in certain embodiments of the invention an electrical signal, e.g., an electrocardiogram (EKG) is simultaneously acquired. The signals are digitized, and, optionally, filtered to remove noise. The invention then processes and analyses the signal(s) so as to provide a clinically relevant conclusion or recommendation such as a diagnosis or suggested additional tests or therapy.

Abstract: An apparatus and method for detecting infrasonic cardiac apical impulses of a patient including a sensor disposable in contact with skin of the patient for producing a signal responsive to a motion of the skin at an infrasonic cardiac apical impulse point of the patient. A first circuit coupled to the first sensor for generating at least one audible output in response to the first signal and indicative of the infrasonic cardiac apical impulse.

Abstract: A method and apparatus for gathering high-quality anatomical audio signals. Practice of the invention, which is illustrated herein in the context of heart-produced signals, is based upon gathering, and competitively processing audio signals collected simultaneously from two adjacent anatomical sites. Competitive processing examines these two signals in light of certain selected “quality” parameters, and thereby selects the better signal at a user-selected point in time.

Abstract: Apparatus and methods that use the acoustic characteristics of vascular blood flow to assess vascular conditions are disclosed. An example method for detecting a change in a vascular condition receives sound information associated with blood flowing through a vascular structure and converts the sound information into data associated with a plurality of cardiac cycles. The example method processes the data associated with the plurality of cardiac cycles to determine an acoustic characteristic associated with a current state of the vascular condition and detects the change in the vascular condition based on a difference between the acoustic characteristic associated with the current state of the vascular condition and a baseline acoustic characteristic associated with an earlier state of the vascular condition.

Abstract: Devices and methods are disclosed for measuring the heart rate of an animal and more specifically, a human. Heart rate measurements are an integral part of many physical examinations. The devices and methods disclosed herein are useful in any field of medicine where a heart rate is measured. The devices utilize a standard medical stethoscope with a removably mounted timer attached thereto. The stethoscope is used by the medical caregiver to listen to cardiac sounds, and more specifically, the heart beats or arterial blood pulses in conjunction with a sphygmomanometer. A countdown timer is attached to the stethoscope between the “Y” and the auscultation head. The countdown timer is actuated by the medical caregiver and the number of cardiac beats are counted until the timer reaches zero. The timer provides an audible warning of timeout and optionally provides a visual indication of timeout.

Abstract: A device for measuring the temperature within a body from a body surface at a different temperature, comprising: a heat shield for application to the body surface, comprising an outer heat-conducting portion (52), and an inner heat-insulating portion (50); a heater or cooler (41) to heat or cool the outer portion (52) of said heat shield to the temperature of the body surface; a first temperature sensor (37) positioned on a surface of the inner heat-insulating portion (50) of the heat shield which is applied to the body surface; a second temperature sensor (38) positioned to measure the temperature of the outer portion (52) of the heat shield; a heater or cooler control circuit to heat or cool the outer portion (52) of the heat shield towards the temperature measured by the first the first temperature sensor (37); and a second control circuit to forecast the first temperature sensor (37) equilibrium temperature.

Abstract: An apparatus for detecting a heart sound of a living subject, including a memory device which stores heart-sound characteristic information which is characteristic of a heart sound of the subject, a heart-sound sensor which is adapted to be worn on a body portion of the subject that is distant from a chest of the subject and which detects, from the body portion, a physical signal containing a heart-sound component and supplies the physical signal, and a heart-sound determining device for determining, based on the heart-sound characteristic information stored in the memory device, the heart-sound component contained in the physical signal.

Abstract: The present invention provides an apparatus for monitoring breath and heart sounds, the apparatus including, sensors for detecting breath and heart sounds, means for recording breath and heart sounds over time and a pattern classifier for comparing recorded breath and heart sounds with previously recorded breath and heart sounds.

Abstract: An acoustic-to-electrical transducer for sensing body sounds is disclosed. The transducer comprises a diaphragm that can be placed in direct contact with a body, whereby the diaphragm motion directly affects an electromagnetic sensing signal, which is then converted to an electrical signal representation of the diaphragm motion. Such sensing means allows the diaphragm to move freely without mechanical coupling to a secondary transducer, while providing a direct and efficient acoustic to electrical conversion means. The transducer further provides a means for using static diaphragm pressure to control gain and frequency characteristics of the electrical signal. The transducer provides methods for ambient noise reduction or cancellation, as well as means for simulating sound detection for applications such as medical education and testing. The sensor, circuitry, manufacturing methods and improvements are disclosed.

Abstract: A hand-held and hand-operated electronic stethoscope sensor module (1) constitutes the core of an equipment kit which in addition to the sensor module (1), comprises at least one extra equipment unit to be attached to the sensor module (1) optionally. The sensor module (1) is provided with interface means adapted to each one of the extra equipment units. Examples of cooperating pairs of extra equipment unit and interface means, are: wireless headset (9) and radio antenna (7) on the module (1); front piece (16) for machine part listening, and front listening surface (3) on the module (1); galvanic safety separation unit (23) and appurtenant connector on the module (1).

Abstract: A releasably interconnectible, signal-communicative interface between an anatomical signal sensor and an associated receiving coupler-adapter. Through complementary male and female interconnection structures, this interface is designed to accommodate both a mechanical, and an electrical, releasably locked cross-connection between such a sensor and a coupler-adapter. Spring-biased cam-interengaging interface components, including a cam surface on the sensor, and a pair of relatively moveable opposed clamping arms on the coupler-adapter operate, during the act of connection, to draw a sensor projection into a connected condition within a socket provided in the coupler-adapter. A springy, electrically conductive component in the adapter plays both mechanical and electrical roles in relation to operation of the interface.

Abstract: A sound input port is ubiquitously present in many types of devices including PCs, PDAs, cell phones, land line phones, and voice recorders thereafter referred to as “computing devices”. A sound port allows data input into a computing device for further computation, visualization and data transmission. Unfortunately most computing devices only allow one channel of data acquisition via the sound port. Further, the acquired data are highpass filtered. A method of extending the signal range to very low frequencies and recording a plurality of data channels via a single sound port is disclosed here. This method uses amplitude modulation of carrier frequencies to create a composite signal. The composite signal is then transmitted into the computing device either via wire or wirelessly. Demodulation occurs in the computing device. In the preferred embodiment the audio signal from an electronic stethoscope and the amplitude modulated EKG are transmitted into a computer via a single microphone port.

Abstract: A sound input port is ubiquitously present in many types of devices including PCs, PDAs, cell phones, land line phones, and voice recorders thereafter referred to as “computing devices”. A sound port allows data input into a computing device for further computation, visualization and data transmission. Unfortunately most computing devices only allow one channel of data acquisition via the sound port. Further, the acquired data are highpass filtered. A method of extending the signal range to very low frequencies and recording a plurality of data channels via a single sound port is disclosed here. This method uses amplitude modulation of carrier frequencies to create a composite signal. The composite signal is then transmitted into the computing device either via wire or wirelessly. Demodulation occurs in the computing device. In the preferred embodiment the audio signal from an electronic stethoscope and the amplitude modulated EKG are transmitted into a computer via a single microphone port.

Abstract: A combined audio and electrical anatomy-signal sensor which is designed to collect, essentially from a selected, common anatomical site, related audio and electrical anatomical signals, such as heart-produced signals. The sensor includes a unique body structure which is designed to function both as a part of the audio-information gathering structure, and as a part of electrical electrode structure for gathering electrical signals. Chamber space is provided within this body for receiving and containing desired electrical circuitry, in the form of circuit-board-supported electrical components, which may be designed to perform any one of a number of different functions relative to signal gathering and transferring at and from an anatomical site.

Abstract: The invention relates to the use of a stethoscope as one part of an interface unit for biological signals. An electroacoustic driver is provided with a signal from e.g. a sound card in a personal computer, and special leak-free coupling means are provided to enable a faithful transmission of the biological signal from e.g. the digital domain in a computer to the ears of a physician used to auscultation—or training to become proficient. The communication of and about physiological signals is remarkably improved with respect to traditional systems.

Abstract: A system and method of detecting a vascular condition within a body receives vibrations emitted in response to blood flowing through a vascular structure within the body and converts the received vibrations into vibration information. The system and method generates spectral information from the vibration information, calculates a spectral parameter based on the spectral information and detects the vascular condition based on the spectral parameter.

Abstract: An electronic stethoscope comprises a headpiece, a chest-piece and two earpieces. The headpiece is fitted with a display arrangement in the form of a liquid-crystal display. A microphone, one or more sensors and fixed electrodes and movable electrodes are mounted in the headpiece. The movable electrodes are fixed to pivoted arms which form a contact ring.

Abstract: A quick-updating stethoscope receiver comprises a receiver, a listening disk at a lower end of the receiver, the listening disk can be embedded into a lower end of the receiver; an upper cover at a top end of the receiver; and a transducer combining at a lateral wall of the receiver and a connector at a rear end of the transducer. A lower end of the receiver has an axial extended shaft. The shaft is formed with an annular trench. An elastic tightening ring is embedded into the trench. A diameter of a cross section of the tightening ring is larger than a depth of the trench so that part of the tightening ring protrudes out of the trench. A center of the round disk has an opening. By the elastic expanding force of the tightening ring, the round disk is tightly engaged to the shaft so that the round disk can not drop out.

Abstract: A fetal heart monitoring system preferably comprising a backing plate having a generally concave front surface and a generally convex back surface, and at least one sensor element attached to the concave front surface for acquiring acoustic fetal heart signals produced by a fetus within a body. The sensor element has a shape that conforms to the generally concave back surface of the backing plate. In one embodiment, the at least one sensor element comprises an inner sensor, and a plurality of outer sensors surrounding the inner sensor. The fetal heart monitoring system can further comprise a web belt, and a web belt guide movably attached to the web belt. The web belt guide being is to the convex back surface of the backing plate.

Abstract: In an electronic stethoscope, a filter unit receives and filters an audio signal attributed to a human body part and received by a receiver so as to output a set of target signals associated with the audio signal. The target signals have frequencies within specific frequency bands and are converted into a set of digital signals. An operating unit is operable so as to generate an input mode signal corresponding to a selected operating mode for selecting one of the digital signals. A processor receives the set of digital signals and the input mode signal, and processes and outputs one of the digital signals that is selected according to the input mode signal. An audio playback unit receives and reproduces output of the processor.

Abstract: An apparatus and method for detecting infrasonic cardiac apical impulses of a patient including a sensor disposable in contact with skin of the patient for producing a signal responsive to a motion of the skin at an infrasonic cardiac apical impulse point of the patient. A first circuit coupled to the first sensor for generating at least one audible output in response to the first signal and indicative of the infrasonic cardiac apical impulse. A dampening ring surrounding the sensor for dampening the relative motion of the sensor with respect to movement of the patient.

Abstract: Methods for identifying and/or visualizing an acoustic window suitable for passive acoustic coronary heart disease evaluations by mapping the relative SNR distribution on the channels on an array of a plurality of sensors to nominal locations on a person's chest of each sensor in the acoustic sensor array and identifying a plurality of sensor locations that correspond to the highest channel SNR's is described and/or sizing the acoustic sensor array to correspond with the identified acoustic window.

Abstract: A biophysical sensor including a sound vibration sensing element (12) to produce a sensed output, and two or more separate signal processing paths to process the sensed outputs to produce output signals. The output signals may reflect specific frequency bands within the raw biological signal. In a further aspect the invention concerns an electronic stethoscope in which the sound vibration sensing element (12) is a PVDF membrane, the signal processing involves an operational amplifier (OP amp) (10) connected to the PVDF membrane, and a unity gain buffer amplifier is connected to the output of the OP amp to allow the connection of headphones directly to the sensor output.

Abstract: Portable equipment including in combination a heart rate measuring device and a sound reproduction unit including means for supplying a signal representative of the sound reproduction and for supplying sound information to a sound transducer, wherein said measuring device and said sound transducer are mounted at least in part in an assembly adapted to be fixed to an ear of a wearer of the equipment and, wherein said sound reproduction unit includes means for optionally substituting for and/or superimposing on said signal representative of said sound reproduction a signal generated from signals from said measuring device and representative of said heart rate. The equipment can take the form of a walkman, for example, or a hearing aid for the hard of hearing.

Abstract: An acoustic-to-electrical transducer for sensing body sounds is provided. The transducer comprises a diaphragm that can be placed in direct contact with a body, whereby the diaphragm motion directly affects an electromagnetic sensing signal, which is then converted to an electrical signal representation of the diaphragm motion. Such sensing means allows the diaphragm to move freely without mechanical coupling to a secondary transducer, while providing a direct and efficient acoustic to electrical conversion means. The transducer further provides a means for using static diaphragm pressure to control gain and frequency characteristics of the electrical signal. The sensor, circuitry, manufacturing methods and improvements are provided.

Abstract: An implantable cardiac rhythm management device capable of automatically detecting intrinsic and evoked response of a patient's heart. The device operates in an automatic capture verification mode, wherein a global accelerometer signal is utilized to identify heart sounds (S1 and S2) of the patient's heart. The presence or absence of one or more of the heart sounds S1 and S2 in the accelerometer signal indicates whether a stimulation pulse evokes a response by the patient's heart. The device may automatically adjust the stimulation output in accordance with a step down stimulation protocol, wherein the presence of a predetermined heart sound indicates capture. Also, the device may suspend the automatic capture verification sequence if the patient's physical activity level exceeds a predetermined threshold.

Abstract: A stethoscope chest piece includes a housing having a rigid contact surface to be pressed against a patient's chest for picking-up sounds therefrom; a mass yieldingly mounted with respect to the housing and the contact surface; and an electrical transducer in the housing and cooperable with the mass and the contact surface to generate an electrical signal corresponding to the displacement of the contact surface relative to the mass. Also described are a stethoscope apparatus including processing circuitry for reducing noise, a loudspeaker for converting the output of the chest piece to sound, various features making the apparatus attractive to children, and a method of using the apparatus for monitoring a physiological condition of a patient.

Abstract: A system and method for use in an implantable cardiac device permits the monitoring of progression and regression in heart disease, such as congestive heart failure. During a monitoring period, a sensing circuit produces an electrogram signal of the patient's heart and a sound sensor produces a phonocardiogram of the patient's heart. A processor determines a predetermined characteristic of the heart sounds, such as amplitude, time intervals between selected heart sounds, and time intervals between selected heart sound and selected electrogram features for each cardiac cycle occurring during a monitoring period. The predetermined characteristics are thereafter averaged and stored in a memory for later retrieval. Relative changes in the average time intervals over time provides an indication of the progression or regression of the heart disease.

Abstract: A diagnostic decision support system provides diagnostic decision support for auditory evaluation of anatomical features and is applicable to virtually any living creature. The system processes an acoustic signal for medical applications by acquiring acoustic data representative of an acoustic signal associated with an anatomical function. The acquired acoustic data is stored in a file associated with a patient medical record. The acquired acoustic data and medical record information is automatically analyzed to determine physiologically significant features useful in medical diagnosis. Information is generated supporting medical diagnosis based on the automatic analysis. In addition, the analysis of the acquired acoustic data may be partially automatic and involve User input of information for use in facilitating diagnostic decision making. The system also processes patient identification information and acoustic test type information (e.g.

Abstract: An esophageal stethoscope includes a tubular flexible body having an acoustic input region. A carrier member, which is separate from the tubular flexible body, is selectively engageable with the tubular flexible body either proximally or distally of the acoustic input region. The carrier member carries one or more devices for providing esophageal recording, monitoring or stimulation functions. For transesophageal cardiac pacing, electrodes are mounted to the carrier member such that engagement of the carrier member with the tubular flexible body functions to convert the esophageal stethoscope to a pacing stethoscope. To carry out a sensing, recording or monitoring function, such as esophageal oximetry, one or more oximetry probes are mounted to the carrier member such that engagement of the carrier member with the esophageal stethoscope converts the stethoscope for use in an oximetry sensing application.

Abstract: A heart-sound analyzing apparatus, including a heart-sound microphone which is adapted to be worn on a living subject to iteratively detect a second heart sound II of the subject, a respiration-synchronous-signal detecting device which iteratively detects a respiration-synchronous signal of the subject, an inspiration-expiration judging device for judging, based on each of the respiration-synchronous signals iteratively detected by the respiration-synchronous-signal detecting device, whether the subject is in an inspiring state or in an expiring state, and an aortic-valve-closing-timing determining device for iteratively determining a timing when the aortic valve of the heart of the subject closes, based on each of second heart sounds II which are iteratively detected by the heart-sound microphone in time intervals, respectively, in each of which the subject is judged as being in the inspiring state by the inspiration-expiration judging device.

Abstract: A sensor designed to collect and convey single-site-related, body-produced electrical and acoustic signals, such as those related to heart activity, where electrical electrode and audio transducer structures lie along a common axis. A portion of the electrical electrode structure forms an acoustic isolating shroud around the audio transducer.

Abstract: Small-scale sensor structure attachable to a person's anatomy for collecting and conveying physiologically-related electrical and audio signals, including the conveying of processed output signals that relate input electrical and audio signals.

Abstract: A hearing aid has an embedded Internet interface so that the hearing aid can automatically communicate error diagnosis data to a hearing aid acoustician via the Internet so that the hearing aid user need not visit the hearing aid acoustician and so that acoustician can initiate appropriate maintenance, training or repair measures. An appertaining method is also provided.

Abstract: An acoustic- to-electrical transducer for sensing body sounds is disclosed. The transducer comprises a diaphragm that can be placed in direct contact with a body, whereby the diaphragm motion directly affects an electromagnetic sensing signal, which is then converted to an electrical signal representation of the diaphragm motion. Such sensing means allows the diaphragm to move freely without mechanical coupling to a secondary transducer, while providing a direct and efficient acoustic to electrical conversion means. The transducer further provides a means for using static diaphragm pressure to control gain and frequency characteristics of the electrical signal. The sensor, circuitry, manufacturing methods and improvements are disclosed.

Abstract: An esophageal stethoscope includes a tubular flexible body having an acoustic input region. A carrier member, which is separate from the tubular flexible body, is selectively engageable with the tubular flexible body either proximally or distally of the acoustic input region. The carrier member carries one or more devices for providing esophageal recording, monitoring or stimulation functions. For transesophageal cardiac pacing, electrodes are mounted to the carrier member such that engagement of the carrier member with the tubular flexible body functions to convert the esophageal stethoscope to a pacing stethoscope. To carry out a sensing, recording or monitoring function, such as esophageal oximetry, one or more oximetry probes are mounted to the carrier member such that engagement of the carrier member with the esophageal stethoscope converts the stethoscope for use in an oximetry sensing application.

Abstract: An esophageal stethoscope includes a tubular flexible body having an acoustic input region. A carrier member, which is separate from the tubular flexible body, is selectively engageable with the tubular flexible body either proximally or distally of the acoustic input region. The carrier member carries one or more devices for providing esophageal recording, monitoring or stimulation functions. For transesophageal cardiac pacing, electrodes are mounted to the carrier member such that engagement of the carrier member with the tubular flexible body functions to convert the esophageal stethoscope to a pacing stethoscope. To carry out a sensing, recording or monitoring function, such as esophageal oximetry, one or more oximetry probes are mounted to the carrier member such that engagement of the carrier member with the esophageal stethoscope converts the stethoscope for use in an oximetry sensing application.

Abstract: An esophageal stethoscope includes a tubular flexible body having an acoustic input region. A carrier member, which is separate from the tubular flexible body, is selectively engageable with the tubular flexible body either proximally or distally of the acoustic input region. The carrier member carries one or more devices for providing esophageal recording, monitoring or stimulation functions. For transesophageal cardiac pacing, electrodes are mounted to the carrier member such that engagement of the carrier member with the tubular flexible body functions to convert the esophageal stethoscope to a pacing stethoscope. To carry out a sensing, recording or monitoring function, such as esophageal oximetry, one or more oximetry probes are mounted to the carrier member such that engagement of the carrier member with the esophageal stethoscope converts the stethoscope for use in an oximetry sensing application.

Abstract: There is disclosed an apparatus and method for detecting very low frequency acoustic signals. The apparatus comprises a sensor that is capable of detecting low frequency acoustic signals in the frequency range of one tenth Hertz to thirty Hertz. The sensor comprises a chamber having portions that form a cavity and a low frequency microphone placed within the cavity. An alternate embodiment of the invention comprises a chamber having portions that form a resonant cavity, a low frequency microphone placed within the resonant cavity, and a membrane that covers the resonant cavity. Low frequency acoustic signals that are incident on the membrane cause the membrane to move and amplify the acoustic signals within the resonant cavity. The sensor provides information concerning physiological conditions, such as respiration and cardiac activity. The sensor in a physiological condition monitor does not need to be directly coupled to the skin of the person being monitored.

Abstract: A protective-sleeve-cartridge/stethoscope assembly includes a stethoscope and a cartridge mounted to the stethoscope, with the cartridge including a sleeve. In a cartridge-and-sleeve assembly, the assembly includes a cartridge having a first elongated circumferential sidewall, with the first elongated circumferential sidewall defining an interior space. The assembly further includes a sleeve, at least a part of which is stored in the interior space. In this assembly, the cartridge and sleeve are constructed and arranged whereby the cartridge may be mounted to a stethoscope, and at least a part of the sleeve may be dispensed from the cartridge interior space and over a head of the stethoscope. A cartridge for mounting to a stethoscope includes a first elongated circumferential sidewall and a second elongated circumferential sidewall inwardly spaced from the first sidewall.

Abstract: A method for extracting features from cardiac acoustic signals includes the steps of obtaining a cardiac acoustic signal, and extracting physiologically significant features from the cardiac acoustic signal using a neural network. A method for evaluating cardiac acoustic signals includes the steps of obtaining a cardiac acoustic signal, analyzing the cardiac acoustic signal with a wavelet decomposition to extract time-frequency information, and identifying basic heart sounds using neural networks applied to the extracted time-frequency information. A method for determining cardiac event sequences from cardiac acoustic signals includes the steps of obtaining a cardiac acoustic signal, and processing a sequence of features extracted from the cardiac acoustic signal by a probabilistic finite-state automaton to determine a most probable sequence of cardiac events given the cardiac acoustic signal.

Abstract: ECG recording apparatus 1 includes a port 2 for connection to ECG electrodes and a microphone 3 for detecting vocal signals, Processing electronics store a recording of the vocal signals and the physiological data on the storage medium 4.

Abstract: A method for extracting features from cardiac acoustic signals includes the steps of obtaining a cardiac acoustic signal, and extracting physiologically significant features from the cardiac acoustic signal using a neural network. A method for evaluating cardiac acoustic signals includes the steps of obtaining a cardiac acoustic signal, analyzing the cardiac acoustic signal with a wavelet decomposition to extract time-frequency information, and identifying basic heart sounds using neural networks applied to the extracted time-frequency information. A method for determining cardiac event sequences from cardiac acoustic signals includes the steps of obtaining a cardiac acoustic signal, and processing a sequence of features extracted from the cardiac acoustic signal by a probabilistic finite-state automation to determine a most probable sequence of cardiac events given the cardiac acoustic signal.

Abstract: A method and an apparatus for measuring the heart rate variability (HRV) are described. A recording of the heart sounds is processed and analyzed with a computing system to obtain various components that characterize the heart rate variability. Since changes of HRV are derived from the sound signals of a heart, which is readily collectable with a microphone or a listening instrument used in auscultation and is readily accessible to patients, a rapid diagnosis and transfer of information are provided. Potential consequences are curtailed and the survivability of patents is thereby enhanced.

Abstract: A fetal heart monitoring system and method for detecting and processing acoustic fetal heart signals transmitted by different signal transmission modes. One signal transmission mode, the direct-contact mode, occurs in a first frequency band when the fetus is in direct contact with the maternal abdominal wall. Another signal transmission mode, the fluid propagation mode, occurs in a second frequency band when the fetus is in a recessed position with no direct contact with the maternal abdominal wall. The second frequency band is relatively higher than the first frequency band. The fetal heart monitoring system and method detect and process acoustic fetal heart signals that are in the first frequency band and in the second frequency band.