SYSTEMS AND METHODS FOR SLEEP APNEA DETECTION FROM BREATHING SOUNDS

• US 20120271199A1
• Filed: 06/19/2012
• Published: 10/25/2012
• Est. Priority Date: 12/29/2009
• Status: Active Grant

• Current Assignee: Rhode Island Board of education (STATE OF RHODE ISLAND)
• Original Assignee: Rhode Island Board of education (STATE OF RHODE ISLAND)
• Inventors: Salisbury, John, Sun, Ying
• Granted Patent: US 9,345,432 B2
• Time in Patent Office: Days
• US Class Current: 600/586
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise
• CPC Class Codes: A61F 5/56 Devices for preventing snoring by influencing the respiratory system by gas treatment A61M16/00

Abstract

A method is disclosed of detecting obstructive sleep apnea in subject. The method includes the steps of placing a head of an electronic stethoscope at the subject'"'"'s suprasternal notch, providing an electrical signal representative of the sounds detected by the head of the electronic stethoscope within a frequency range, determining an obstructive sleep apnea index based on a ratio of the amount of the electrical signal that is associated with a frequency below a cut-off frequency with respect to a total amount of energy associated with the entire frequency range, and identifying the subject as having obstructive sleep apnea if the obstructive sleep apnea index is above a window maximum or below a window minimum.

Claims

1. A method of detecting obstructive sleep apnea in subject, said method comprising the steps of:

placing a head of an electronic stethoscope at the subject'"'"'s suprasternal notch;

providing an electrical signal representative of the sounds detected by the head of the electronic stethoscope within a frequency range,

determining an obstructive sleep apnea index based on a ratio of the amount of the electrical signal that is associated with a frequency below a cut-off frequency with respect to a total amount of energy associated with the entire frequency range; and

identifying the subject as having obstructive sleep apnea if the obstructive sleep apnea index is above a window maximum or below a window minimum.

2. The method as claimed in claim 1, wherein said cut-off frequency is about 100 Hz.

3. The method as claimed in claim 1, wherein said frequency range is between about 20 Hz and about 800 Hz.

4. The method as claimed in claim 1, wherein said window maximum is about 80%.

5. The method as claimed in claim 1, wherein said window minimum is about 25%.

6. The method as claimed in claim 1, wherein said method further includes the step of identifying the subject as not having obstructive sleep apnea if the obstructive sleep apnea index is within a window defined between the window maximum and the window minimum.

7. The method as claimed in claim 1, wherein said method is performed using an electronic stethoscope that includes a processor for performing the steps of determining the obstructive sleep apnea index and identifying the subject as having obstructive sleep apnea if the obstructive sleep apnea index is above the window maximum or below the window minimum.

8. A method of detecting obstructive sleep apnea in subject, said method comprising the steps of:

placing a head of an electronic stethoscope at the subject'"'"'s suprasternal notch;

providing an analog electrical signal representative of the sounds detected by the head of the electronic stethoscope within a frequency range;

receiving the analog electrical signal and providing a digitized electrical signal that is representative of the analog electrical signal with the frequency range;

applying a fast Fourier transform to the digitized electrical signal;

determining an obstructive sleep apnea index based on a ratio of the amount of the electrical signal that is associated with a frequency below a cut-off frequency with respect to a total amount of energy associated with the entire frequency range;

identifying the subject as having obstructive sleep apnea if the obstructive sleep apnea index is above a window maximum or below a window minimum; and

identifying the subject as not having obstructive sleep apnea if the obstructive sleep apnea index is within a window defined by the window maximum and the window minimum.

9. The method as claimed in claim 8, wherein said cut-off frequency is about 100 Hz.

10. The method as claimed in claim 8, wherein said frequency range is between about 20 Hz and about 800 Hz.

11. The method as claimed in claim 8, wherein said window maximum is about 80%.

12. The method as claimed in claim 8, wherein said window minimum is about 25%.

13. The method as claimed in claim 8, wherein said method is performed using an electronic stethoscope that includes a processor for performing the steps of determining the obstructive sleep apnea index and identifying the subject as having obstructive sleep apnea if the obstructive sleep apnea index is above the window maximum or below the window minimum.

14. A system for detecting obstructive sleep apnea in subject, said system comprising:

an electronic stethoscope having a head for application to a subject;

a processor for determining an obstructive sleep apnea index based on a ratio of the amount of the electrical signal that is associated with a frequency below a cut-off frequency with respect to a total amount of energy associated with the entire frequency range, and for determining whether the obstructive sleep apnea index is above a window maximum or below a window minimum; and

a display for providing an identification of whether the subject has obstructive sleep apnea responsive to whether the obstructive sleep apnea index is above the window maximum or below the window minimum.

15. The system as claimed in claim 14, wherein said processor and said display are provided within the electronic stethoscope.