Method of detecting the wearing limb of a wearable electronic device

• US 10,045,708 B2
• Filed: 04/15/2016
• Issued: 08/14/2018
• Est. Priority Date: 08/26/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Dusan, Sorin V.
• Primary Examiner(s): MAHMOOD, NADIA AHMAD
• Application Number:
  US15/130,616
• Publication Number:
  US 20160228025A1
• Time in Patent Office: 851 Days
• Field of Search: 600500, 600509
• CPC Class Codes: A61B 2505/07 Home care
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/25 Bioelectric electrodes therefor
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/332 Portable devices specially adapted therefor
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6841 by using templates
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: G06F 2218/12 Classification; Matching
• CPC Class Codes: G16H 40/63 for local operation

Abstract

A wearable device configured to acquire and process electrocardiographic measurements, detect lead inversion and correct the acquired measurements for lead inversion is provided. In one example, the wearable device can detect lead inversion by first assessing whether the P-wave of a given electrocardiographic measurement has a negative amplitude, and if the P-wave is found to be negative, the device can determine if the magnitude of the R-wave is smaller than the maximum of the magnitudes of the S-wave and the Q-wave. In another example, the device can be put through an enrollment procedure in which electrocardiographic measurements are taken with the device being worn at known locations on the body. Once the enrollment procedure is completed, when the device is being used, any electrocardiographic results obtained can be compared against the measurements taken during the enrollment phase, and the location of the device on the body can be determined.

Claims

1. A device capable of measuring electrocardiographic signals, the device comprising:

a first electrode configured to come into contact with a first portion of a user'"'"'s body and configured to measure an electrical potential at the first portion of the user'"'"'s body;

a second electrode configured to come into contact with a second portion of the user'"'"'s body and configured to measure an electrical potential at the second portion of the user'"'"'s body; and

a processor capable of;

measuring a potential difference between the first electrode and the second electrode;

determining whether the first electrode and second electrode have been inverted based on the measured potential difference between the first electrode and the second electrode, wherein determining whether the first electrode and second electrode have been inverted includes identifying a P-wave, an R-wave, a Q-wave, and an S-wave from the measured potential difference; and

compensating the measured potential difference if the first and second electrodes are determined to be inverted.

2. The device of claim 1, wherein determining whether the first electrode and the second electrode have been inverted further includes determining if the P-wave exhibits a characteristic indicative of inversion of the first and second electrodes.

3. The device of claim 2, wherein determining whether the first electrode and the second electrode have been inverted further includes comparing an amplitude of the R-wave to a maximum of absolute values of amplitudes of the Q-wave and the S-wave, if the amplitude of the P-wave is lower than a pre-determined threshold.

4. The device of claim 1, wherein the processor is further capable of determining a location on the user'"'"'s body of the first electrode and a location on the user'"'"'s body of the second electrode based on the determination of whether the first electrode and the second electrode have been inverted.

5. A method of detecting and correcting lead inversion in an electrocardiographic measurement, the method comprising:

measuring a potential difference between a first electrode and a second electrode, the first electrode and second electrode being in contact with a first portion and a second portion respectively of a user'"'"'s body;

determining whether the first electrode and second electrode have been inverted based on the measured potential difference between the first electrode and the second electrode, wherein determining whether the first electrode and second electrode have been inverted includes identifying a P-wave, an R-wave, a Q-wave, and an S-wave from the measured potential difference; and

compensating the measured potential difference if the first and second electrodes are determined to be inverted.

6. The method of claim 5, wherein determining whether the first electrode and the second electrode have been inverted further includes determining if the P-wave exhibits a characteristic indicative of inversion of the first and second electrodes.

7. The method of claim 6, wherein determining whether the first electrode and the second electrode have been inverted further includes comparing an amplitude of the R-wave to a maximum of absolute values of amplitudes of the Q-wave and the S-wave, if the amplitude of the P-wave is lower than a pre-determined threshold.

8. The method of claim 5, the method further comprising determining a location on the user'"'"'s body of the first electrode and a location on the user'"'"'s body of the second electrode based on the determination of whether the first electrode and the second electrode have been inverted.

9. A non-transitory computer readable storage medium having stored thereon a set of instructions for detecting and correcting lead inversion in an electrocardiographic measurement, that when executed by a processor causes the processor to:

measure a potential difference between a first electrode and a second electrode, the first electrode and second electrode being in contact with a first portion and a second portion respectively of a user'"'"'s body;

determine whether the first electrode and second electrode have been inverted based on the measured potential difference between the first electrode and the second electrode, wherein determining whether the first electrode and second electrode have been inverted includes identifying a P-wave, an R-wave, a Q-wave, and an S-wave from the measured potential difference; and

compensate the measured potential difference if the first and second electrodes are determined to be inverted.

10. The non-transitory computer readable storage medium of claim 9, wherein determining whether the first electrode and the second electrode have been inverted further includes determining if the P-wave exhibits a characteristic indicative of inversion of the first and second electrodes.

11. The non-transitory computer readable storage medium of claim 10, wherein determining whether the first electrode and the second electrode have been inverted further includes comparing an amplitude of the R-wave to a maximum of absolute values of amplitudes of the Q-wave and the S-wave, if the amplitude of the P-wave is lower than a pre-determined threshold.

12. The non-transitory computer readable storage medium of claim 9, the processor being further caused to determine a location on the user'"'"'s body of the first electrode and a location on the user'"'"'s body of the second electrode based on the determination of whether the first electrode and the second electrode have been inverted.

13. A device capable of measuring electrocardiographic signals, the device comprising:

a first electrode configured to come into contact with a first portion of the user'"'"'s body and configured to measure an electrical potential at the first portion of the user'"'"'s body;

a second electrode configured to come into contact with a second portion of the user'"'"'s body and configured to measure an electrical potential at the second portion of the user'"'"'s body; and

a processor capable of;

measuring a potential difference between the first electrode and the second electrode; and

determining whether the first electrode and the second electrode have been inverted based on the measured potential difference between the first electrode and the second electrode, wherein determining whether the first electrode and the second electrode have been inverted includes comparing the measured potential difference to a plurality of electrocardiographic measurements stored in a memory of the device.

14. The device of claim 13, wherein the plurality of electrocardiographic measurements are obtained in an enrollment phase of the device, wherein during the enrollment phase the first electrode and the second electrode are placed in a plurality of known locations on the user'"'"'s body to generate the plurality of electrocardiographic measurements.

15. The device of claim 13, wherein comparing the measured potential difference to a plurality of electrocardiographic measurements stored in a memory of the device includes generating a cross-correlation factor between the measured potential difference and each of the electrocardiographic measurements stored in the memory of the device.

16. The device of claim 15, wherein the processor is further capable of determining a location on the user'"'"'s body of the first electrode and a location on the user'"'"'s body of the second electrode based on the plurality of correlation factors generated.

17. A method of detecting and correcting lead inversion in an electrocardiographic measurement, the method comprising:

measuring a potential difference between a first electrode and a second electrode, the first electrode and second electrode being in contact with a first portion and a second portion respectively of a user'"'"'s body;

determining whether the first electrode and the second electrode have been inverted based on the measured potential difference between the first electrode and the second electrode, wherein determining whether the first electrode and the second electrode have been inverted includes comparing the measured potential difference to a plurality of stored electrocardiographic measurements; and

compensating the measured potential difference if the first and second electrodes are determined to be inverted.

18. The method of claim 17, wherein the plurality of electrocardiographic measurements are obtained by placing the first electrode and the second electrode in a plurality of known locations on the user'"'"'s body to generate the plurality of stored electrocardiographic measurements.

19. The method of claim 17, wherein comparing the measured potential difference to a plurality of electrocardiographic measurements includes generating a cross-correlation factor between the measured potential difference and each of the stored electrocardiographic measurements of the plurality of stored electrocardiographic measurements.

20. The method of claim 19, wherein the method further comprises determining a location on the user'"'"'s body of the first electrode and a location on the user'"'"'s body of the second electrode based on the plurality of correlation factors generated.

21. A non-transitory computer readable storage medium having stored thereon a set of instructions for detecting and correcting lead inversion in an electrocardiographic measurement, that when executed by a processor causes the processor to:

measure a potential difference between a first electrode and a second electrode, the first electrode and second electrode being in contact with a first portion and a second portion respectively of a user'"'"'s body;

determine whether the first electrode and the second electrode have been inverted based on the measured potential difference between the first electrode and the second electrode, wherein determining whether the first electrode and the second electrode have been inverted includes comparing the measured potential difference to a plurality of electrocardiographic measurements stored in a memory; and

compensate the measured potential difference if the first and second electrodes are determined to be inverted.

22. The non-transitory computer readable storage medium of claim 21, wherein the plurality of electrocardiographic measurements are obtained by placing the first electrode and the second electrode in a plurality of known locations on the user'"'"'s body to generate the plurality of stored electrocardiographic measurements.

23. The non-transitory computer readable storage medium of claim 21, wherein comparing the measured potential difference to a plurality of electrocardiographic measurements includes generating a cross-correlation factor between the measured potential difference and each of the stored electrocardiographic measurements of the plurality of stored electrocardiographic measurements.

24. The non-transitory computer readable storage medium of claim 23, wherein the set of instructions further causes the processor to determine a location on the user'"'"'s body of the first electrode and a location on the user'"'"'s body of the second electrode based on the plurality of correlation factors generated.