BREATHING SOUND ANALYSIS FOR DETECTION OF SLEEP APNEA/POPNEA EVENTS

• US 20080243014A1
• Filed: 03/28/2007
• Published: 10/02/2008
• Est. Priority Date: 03/28/2007
• Status: Active Grant

• Current Assignee: TR Technologies Incorporated
• Original Assignee: TR Technologies Incorporated
• Inventors: Yadollahi, Azadeh, Moussavi, Zahra, Camorlinga, Sergio
• Granted Patent: US 7,559,903 B2
• Time in Patent Office: Days
• US Class Current: 600/529
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/6815 Ear
• CPC Class Codes: A61B 5/6822 Neck
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

Apparatus for use detection of apnea includes a microphone mounted in the ear of the patient for detecting breathing sounds and a second external microphone together with an oximetric sensor. A transmitter at the patient compresses and transmits the signals to a remote location where there is provided a detector module for receiving and analyzing the signals to extract data relating to the breathing. The detector uses the entropy or range of the signal to generate an estimate of air flow while extracting extraneous snoring and heart sounds and to analyze the estimate of air flow using Otsu'"'"'s threshold to detect periods of apnea and/or hypopnea. A display provides data of the detected apnea/hypopnea episodes and related information for a clinician.

Claims

1. Apparatus for use in use in analysis of breathing of a patient during sleep for detection of apnea comprising:

a microphone arranged to be located on the patient for detecting breathing sounds;

the microphone being arranged so as to be attached on the neck of the patient so as to receive sounds in the neck emanating from the breathing of the patient;

a transmitter at the patient for transmitting signals from the breathing sounds to a remote location;

a detector module for receiving and analyzing the signals to extract data relating to the breathing;

the detector module being arranged to analyze the signals including signals in a frequency range greater than 75Hz, while extracting extraneous sounds related to snoring and/or heart, to detect periods of apnea and/or hypopnea;

and a display of the detected apnea/hypopnea episodes and related information for a clinician.

2. The apparatus according to claim 1 wherein there is provided a second microphone to collect extraneous sounds from the patient and a sensor for oximetric signals for transmission to the remote receiver.

3. The apparatus according to claim 1 wherein the transmitter is arranged to compress data for transmission.

4. The apparatus according to claim 1 wherein the remote receiver and detector module are arranged to receive signals from a plurality of transmitters at different locations through an organizer module.

5. The apparatus according to claim 1 wherein the detector module connects to an interface for transmission of data to different locations.

6. The apparatus according to claim 1 wherein there is provided a second microphone arranged to receive sounds from the patient in the vicinity of the patient so as to be sensitive to snoring and wherein the detector module is arranged to use adaptive filtering to extract the signals relating to the snoring from the signals including both the breathing sounds and the snoring sounds.

10. The apparatus according to claim 1 wherein the detector module is arranged to generate an estimate of air flow during breathing by calculating a function representing the range of the signals wherein the range of signal is defined as the log of the difference between minimum and maximum of the signal within each window of data.

11. The apparatus according to claim 1 wherein the detector module is arranged to generate an estimate of air flow during breathing by calculating a function representing the entropy of the signals wherein the function is the entropy of the signal which is defined by the following formula:

12. The apparatus according to claim 10 wherein sleep apnea and/or hypopnea is detected by comparing the function to a threshold.

13. The apparatus according to claim 12 wherein the threshold is defined as the minimum of the Otsu'"'"'s threshold and the average value of the function within each data window.

14. The apparatus according to claim 13 wherein the Otsu'"'"'s threshold is defined as the threshold which maximizes the between class variance.

15. The apparatus according to claim 1 wherein the display includes a display of airflow versus time is plotted with apnea and hypopnea episodes marked in.

7. (canceled)

8. (canceled)

9. (canceled)

16. Apparatus for use in use in analysis of breathing of a patient during sleep for detection of apnea comprising:

a microphone arranged to be located on the patient for detecting breathing sounds;

a transmitter at the patient for transmitting signals from the breathing sounds to a remote location;

a detector module for receiving and analyzing the signals to extract data relating to the breathing;

the detector module being arranged to analyze the signals, while extracting extraneous sounds related to snoring and/or heart, to detect periods of apnea and/or hypopnea;

and a display of the detected apnea/hypopnea episodes and related information for a clinician;

wherein the display includes oximetry data plotted in association with the estimated airflow.

17. The apparatus according to claim 16 wherein the display is capable of zoom-in and zoom-out functions in the same window for both airflow and oximetry data simultaneously.

18. The apparatus according to claim 16 wherein the display is capable of playing the breathing and snoring sounds in any zoomed-in or zoomed-out data window.

19. The apparatus according to claim 16 wherein the display is capable of displaying the extracted information about the frequency and duration of apnea/hypopnea episodes, and their association with the level of oximetry data in a separate window for the clinician.

20. Apparatus for use in analysis of breathing of a patient during sleep for detection of apnea comprising:

a microphone arranged to be located on the patient for detecting breathing sounds;

a transmitter at the patient for transmitting signals from the breathing sounds to a remote location;

a detector module for receiving and analyzing the signals to extract data relating to the breathing;

the detector module being arranged to analyze the signals, while extracting extraneous sounds related to snoring and/or heart, to detect periods of apnea and/or hypopnea;

and a display of the detected apnea/hypopnea episodes and related information for a clinician;

wherein the microphone is arranged to be located in the ear of the patient so as to receive sounds emanating from the breathing of the patient.

21. The apparatus according to claim 20 wherein the microphone in the ear includes a transmitter arranged for wireless transmission to a receiver.

22. Apparatus for use in use in analysis of breathing of a patient during sleep for detection of apnea comprising:

a microphone arranged to be located on the patient for detecting breathing sounds;

a transmitter at the patient for transmitting signals from the breathing sounds to a remote location

a detector module for receiving and analyzing the signals to extract data relating to the breathing;

the detector module being arranged to analyze the signals to generate an estimate of air flow while extracting extraneous sounds related to snoring and/or heart;

the detector module being arranged to analyze the estimate of air flow to detect periods of apnea and/or hypopnea;

and a display of the detected apnea/hypopnea episodes and related information for a clinician;

wherein the detector module is arranged to generate an estimate of air flow during breathing by calculating a function representing the range of the signals which is defined as the log of the difference between minimum and maximum of the signal within each window of data.

23. Apparatus for use in use in analysis of breathing of a patient during sleep for detection of apnea comprising:

a microphone arranged to be located on the patient for detecting breathing sounds;

a transmitter at the patient for transmitting signals from the breathing sounds to a remote location;

a detector module for receiving and analyzing the signals to extract data relating to the breathing;

the detector module being arranged to analyze the signals, while extracting extraneous sounds related to snoring and/or heart, to detect periods of apnea and/or hypopnea;

and a display of the detected apnea/hypopnea episodes and related information for a clinician;

wherein the detector module is arranged to generate an estimate of air flow during breathing by calculating a function representing the entropy of the signals where entropy is defined by the following formula;