Automated Diagnosis-Assisting Medical Devices

• US 20140276133A1
• Filed: 04/03/2014
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Abandoned Application

• Current Assignee: CSD Labs GmbH
• Original Assignee: CSD Labs GmbH
• Inventors: Schriefl, Andreas J., Reinisch, Andreas J.
• Application Number:
  US14/244,873
• Publication Number:
  US 20140276133A1
• Time in Patent Office: Days
• US Class Current: 600/484
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7235 Details of waveform analysis A61B5/349 takes precedence
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61B 5/7405 using sound
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: G06F 2218/10 by analysing the shape of a waveform, e.g. extracting parameters relating to peaks

Abstract

A system includes an electronic stethoscope producing a quasi-periodic signal, a processor, and a memory device with stored instructions that, when executed by the processor, cause the system to receive a representation of the quasi-periodic signal, to remove a DC component from the received representation of the quasi-periodic signal to produce a purely time-varying signal, and to filter, the time-varying signal to produce a pre-processed signal. A portion of the pre-processed signal is auto-correlated with itself, and a corresponding auto-correlation output is stored. A biphasic tapering function is applied to the auto-correlation output and produces a first maximum, the function including a time constant parameter that is a function of the quasi-periodic signal. A representation is stored, based on the first maximum, as an indication of a rate or frequency of the quasi-periodic signal.

Claims

1. A system for processing a quasi-periodic signal, the system comprising:

an electronic stethoscope producing a quasi-periodic signal;

a processor; and

a memory device with stored instructions that, when executed by the processor, cause the system to;

receive a representation of the quasi-periodic signal,

remove a DC component from the received representation of the quasi-periodic signal to produce a purely time-varying signal,

filter, the time-varying signal to produce a pre-processed signal,

auto-correlate, at least a portion of a representation of the pre-processed signal with itself,

store a corresponding auto-correlation output for the at least portion of the representation of the pre-processed signal,

apply a biphasic tapering function to the auto-correlation output, the tapering function including a time constant parameter that is a function of the quasi-periodic signal and producing a first maximum, and

store in the memory device a representation, based on the first maximum, as an indication of a rate or a frequency of the quasi-periodic signal.

2. The system of claim 1, wherein the representation of the quasi-periodic signal includes a heartbeat and a respiration.

3. The system of claim 1, wherein the memory device further causes the system to provide selectable settings of the electronic stethoscope and to communicate between a user of the electronic stethoscope and a medical professional.

4. The system of claim 1, wherein the memory device further causes the system to provide an indication of the rate or the frequency of the quasi-periodic signal directly on a device selected from a group consisting of the electronic stethoscope, a second device attached to the electronic stethoscope, and a third device in wireless communication with the electronic stethoscope.

5. The system of claim 1, wherein the memory device further causes the system to:

estimate the rate or the frequency of the quasi-periodic signal;

define a search window based on the estimated rate or frequency of the quasi-periodic signal;

define a starting position in the received quasi-periodic signal, the starting position corresponding to the first maximum;

cross-correlate a portion of the quasi-periodic signal in the search window with a template signal pattern to be matched to produce a second maximum that is defined by the controller as a new starting position; and

store the new starting position.

6. The system of claim 5, wherein the memory device further causes the system to:

determine a localized pattern of the template signal pattern;

extract a signal segment from the localized pattern;

analyze the signal segment simultaneously in time and frequency domains to produce parallel outputs;

combine the parallel outputs via a statistical or mathematical function to produce a result; and

automatically indicate a diagnosis based on the result.

7. The system of claim 6, wherein the memory device further causes the system to indicate the diagnosis directly on a device selected from a group consisting of the electronic stethoscope, a second device attached to the electronic stethoscope, and a third device in wireless communication with the electronic stethoscope.

8. The system of claim 6, wherein the memory device further causes the system to indicate the diagnosis via one or more of a display and audio output of a portable device.

9. The system of claim 1, wherein the memory device further causes the system to:

share with one or more portable devices data associated with the representation; and

display the data on displays of the one or more portable devices.

10. A system for processing a quasi-periodic signal, the system comprising:

an electronic stethoscope producing a quasi-periodic signal;

a processor; and

a memory device with stored instructions that, when executed by the processor, cause the system to;

in response to receiving a representation of the quasi-periodic signal, produce a pre-processed time-varying signal,

produce an auto-correlation output corresponding to an auto-correlation of at least a portion of a representation of the pre-processed time-varying signal with itself,

in response to applying a biphasic tapering function to the auto-correlation output, estimate a frequency of the quasi-periodic signal,

define a search window based on the estimated frequency of the quasi-periodic signal;

define a starting position in the received quasi-periodic signal, the starting position corresponding to a first maximum;

cross-correlate a portion of the quasi-periodic signal in the search window with a template signal pattern to be matched to produce a second maximum that is defined by the controller as a new starting position; and

store the new starting position.

11. The system of claim 10, wherein the electronic stethoscope includes selectable settings for communicating between a user of the electronic stethoscope and a medical professional.

12. The system of claim 10, wherein the electronic stethoscope includes an indication of the frequency of the quasi-periodic signal.

13. The system of claim 10, wherein the memory device further causes the system to provide an indication of the rate or the frequency of the quasi-periodic signal directly on a device selected from a group consisting of the electronic stethoscope, a second device attached to the electronic stethoscope, and a third device in wireless communication with the electronic stethoscope.

14. The system of claim 10, wherein the memory device further causes the system to:

determine a localized pattern of the template signal pattern;

extract a signal segment from the localized pattern;

analyze the signal segment simultaneously in time and frequency domains to produce parallel outputs;

combine the parallel outputs via a statistical or mathematical function to produce a result; and

automatically indicate a diagnosis based on the result.

15. The system of claim 14, wherein the electronic stethoscope further includes at least one of a display and an audio output feature, the memory device further causing the system to indicate the diagnosis via one or more of the display and the audio output feature.

16. The system of claim 10, wherein the electronic stethoscope includes a data connection, the memory device further causing the system to:

share, via the data connection, the representation of the frequency with a hospital information system;

retrieve a patient list from the hospital information system;

select a patient from the patient list;

obtain patient specific parameters associated with the representation of the frequency; and

transfer to the hospital information system one or more of patient data, raw auscultation data, the patient specific parameters, and a diagnosis suggestion.

17. The system of claim 10, wherein the memory device further causes the system to:

send raw data of the frequency of the quasi-periodic signal to a hospital information system;

analyze the raw data at the hospital information system; and

store results of the analysis at the hospital information system for later review by a medical professional.

18. The system of claim 10, wherein the memory device further causes the system to:

remove a DC component from the received representation of the quasi-periodic signal to produce a purely time-varying signal, and

filter, the time-varying signal to produce the pre-processed time-varying signal.

19. The system of claim 10, wherein the tapering function including a time constant parameter that is a function of the quasi-periodic signal, the memory device further causing the system to:

store the auto-correlation output;

in response to applying the biphasic tapering function to the auto-correlation output, produce the first maximum; and

store a representation, based on the first maximum, indicative of the frequency of the quasi-periodic signal.

20. The system of claim 19, further comprising a portable device, the memory device further causing the system to:

save the representation indicative of the frequency in a file of a predetermined file format;

send the file in an e-mail;

print the file; and

store the file on the portable device.