Apparatus and method for identifying sleep disordered breathing

• US 6,942,626 B2
• Filed: 07/22/2004
• Issued: 09/13/2005
• Est. Priority Date: 07/24/2003
• Status: Expired due to Fees

• Current Assignee: VANGUARD TECHNOLOGIES, LLC
• Original Assignee: Predictive Technologies
• Inventors: Dodenhoff, Tracey A., Salisbury, John I.
• Primary Examiner(s): Nasser, Robert
• Assistant Examiner(s): MALLARI, PATRICIA C
• Application Number:
  US10/897,304
• Publication Number:
  US 20050020930A1
• Time in Patent Office: 418 Days
• Field of Search: 600/300, 600/301, 600/508, 600/509, 600529-543, 607/2, 607/6, 607/17, 607/18, 702189-191, 702193-197
• US Class Current: 600/538
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/4806 Sleep evaluation A61B5/4821 takes precedence; devices for inducing sleep A61M21/02
• CPC Class Codes: A61B 5/4818 Sleep apnoea

Abstract

An apparatus and method for identifying sleep disordered breathing while the patient is awake. The device includes collection of raw data which is normalized, then conditioned and transformed for comparison against a threshold, enabling identification of the presence of and severity of sleep disordered breathing. Step 1 is the collection of raw data and normalization. Step 2 is the conditioning of the data (using Empirical Mode Decomposition or similar technique). Step 3 is the selection of several components in the conditioned data. Step 4 is the performing of a Hilbert transform on the conditioned data. Step 5 is selecting a constant frequency. Step 6 is charting output against a threshold. Step 7 is identifying the patient'"'"'s condition based on an array of amplitudes and the threshold.

Claims

1. A method for identifying sleep disordered breathing of a patient, the method comprising:

collecting data of at least one cardio-respiratory function of the patient over time;

generating a plurality of intrinsic mode functions from the data;

generating an array of frequencies, times, and amplitudes based on at least one intrinsic mode function;

generating an array of times and amplitudes based on a selected frequency; and

identifying sleep disordered breathing of the patient from the generated amplitudes.

2. The method of claim 1 further including grouping the amplitudes from the array of times and amplitudes into a plurality of bins, each bin including amplitudes being within a predetermined range of magnitudes.

3. The method of claim 2 further including determining a cumulative number of amplitudes within a selected number of bins.

4. The method of claim 3 wherein the selected bins include amplitudes having the lowest magnitudes.

5. The method of claim 4 wherein identifying sleep disordered breathing includes comparing the cumulative number of amplitudes with a threshold.

6. The method of claim 5 wherein if the cumulative number of amplitudes is less than the threshold then the patient has sleep disordered breathing.

7. The method of claim 2 wherein the data includes respiratory airflow data.

8. The method of claim 2 wherein the data is collected while the patient is awake.

9. The method of claim 2 wherein the plurality of intrinsic mode functions is generated using Empirical Mode Decomposition.

10. The method of claim 2 wherein two intrinsic mode functions are selected.

11. The method of claim 2 wherein the array of frequencies, times, and amplitudes is generated from a Hilbert transform.

12. The method of claim 2 wherein a graphical representation represents the plurality of bins.

13. The method of claim 12 wherein the graphical representation is a histogram.

14. The method of claim 2 wherein the collected data is normalized.

15. A method for identifying sleep disordered breathing of a patient, the method comprising:

collecting air flow data of the patient over time while the patient is awake;

normalizing the air flow data;

generating a plurality of intrinsic mode functions from the data using Empirical Mode Decomposition;

selecting at least two intrinsic mode functions;

performing a Hilbert transform on the two intrinsic mode functions to generate an array of frequencies, times, and amplitudes;

generating an array of times and amplitudes based on a selected frequency;

grouping the amplitudes from the array of times and amplitudes into a plurality of bins, each bin including amplitudes being within a predetermined range of magnitudes;

determining a cumulative number of amplitudes within a selected number of bins, the selected bins including amplitudes having the lowest magnitudes; and

diagnosing the patient with sleep disordered breathing if the cumulative number of amplitudes is less than a threshold.

16. The method of claim 15 wherein the selected frequency is 1.5 Hz.

17. The method of claim 15 wherein the selected number of bins is 20.

18. The method of claim 15 wherein the threshold is 300.

19. An apparatus for identifying sleep disordered breathing of a patient comprising:

collecting means for collecting data of at least one cardio-respiratory function of the patient over time;

first means for generating a plurality of intrinsic mode functions from the data;

second means for generating an array of frequencies, times, and amplitudes based on at least one intrinsic mode function;

third means for generating an array of times and amplitudes based on a selected frequency; and

identifying means for identifying sleep disordered breathing of the patient from the generated amplitudes.

20. The apparatus of claim 19 further including grouping means for grouping the amplitudes from the array of times and amplitudes into a plurality of bins, each bin including amplitudes being within a predetermined range of magnitudes.