Sleep position detection

• US 9,649,043 B2
• Filed: 12/09/2008
• Issued: 05/16/2017
• Est. Priority Date: 12/12/2007
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Meftah, Mohammed, Brauers, Andreas
• Primary Examiner(s): Gedeon, Brian T
• Assistant Examiner(s): Tejani, Ankit D
• Application Number:
  US12/747,176
• Publication Number:
  US 20100262026A1
• Time in Patent Office: 3,080 Days
• Field of Search: None
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/1114 Tracking parts of the body
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61B 5/4806 Sleep evaluation A61B5/4821 takes precedence; devices for inducing sleep A61M21/02
• CPC Class Codes: A61B 5/6887 mounted on external non-worn devices, e.g. non-medical devices
• CPC Class Codes: A61B 5/6892 Mats

Abstract

A method of determining body position uses ECG sensors at fixed positions, not fixed to the patient. The ECG signals recorded from the sensors are used to detect body position, using the variation of ECG potential over the surface of the body. The results may be processed by measuring artifacts related to the angle between the sensors and the heart, in particular the polarity of the QRS complex. The sensors may be fixed on the upper surface of a bed and used to measure sleep position.

Claims

1. Apparatus for measuring body position, comprising:

at least two biometric sensors arranged in a fixed position with respect to a body support, for measuring at least one electrocardiogram signal from a body, wherein the at least one electrocardiogram signal changes with the body position as a result of variation of electrocardiogram potential over the surface of the body; and

a processing means arranged to capture the at least one electrocardiogram signal from the biometric sensors, and to determine the body position from the captured at least one electrocardiogram signal using the variation of electrocardiogram potential over the surface of the body;

wherein the processing means is adapted to determine a polarity of a QRS complex of the at least one electrocardiogram signal to determine an orientation of a heart of the body with respect to a respective pair of the biometric sensors providing the at least one electrocardiogram signal.

2. Apparatus according to claim 1, wherein a plurality of the biometric sensors are arranged in an array distributed across the body support.

3. Apparatus according to claim 1, comprising a bed that includes the body support, and the biometric sensors are arranged fixed in the bed.

4. Apparatus according to claim 3, wherein the biometric sensors are arranged on an upper sleeping surface of the bed.

5. Apparatus according to claim 1 wherein the processing means is arranged to capture a plurality of electrocardiogram signals measured from a respective plurality of the biometric sensors and to determine the body position from the plurality of electrocardiogram signals.

6. Apparatus according to claim 1 wherein the processing means is adapted to compare the QRS complex of the at least one electrocardiogram signal with a plurality of prerecorded electrocardiogram signals in respective body positions and to identify a closest match.

7. Apparatus according to claim 1 wherein the biometric sensors are capacitive electrodes.

8. Apparatus according to claim 1 wherein the biometric sensors are contact electrodes, the apparatus further comprising a conductive foot contact and/or conductive pillow on an upper surface of the body support to serve as a return path for electrical current.

9. A method of measuring body position, comprising:

supporting a body on a body support having electrocardiogram sensors fixed with respect to the body support;

capturing at least one electrocardiogram signal from respective electrocardiogram sensors, the at least one electrocardiogram signal changing with body position as a result of variation of electrocardiogram potential over the surface of the body; and

determining the body position from the at least one electrocardiogram signal using the variation of electrocardiogram potential over the surface of the body;

wherein the determining of the body position from the at least one electrocardiogram signal includes;

determining a polarity of the QRS complex of the at least one electrocardiogram signal, and

determining an angle between an electrical axis of a heart of the body and an orientation of a respective pair of the electrocardiogram sensors from the polarity of the QRS complex.

10. A method according to claim 9, wherein the determining of the body position from the at least one electrocardiogram signal includes comparing the QRS complex of each electrocardiogram signal with a plurality of prerecorded electrocardiogram signals in respective body positions and identifies the closest match.

11. A method according to claim 9 wherein the electrocardiogram sensors are arranged as an array over the surface of a bed and the measuring of body position includes determining which electrocardiogram sensors of the array can detect the at least one electrocardiogram signal and measuring the body position from the at least one electrocardiogram signals from the determined electrocardiogram sensors.

12. The method of claim 9, wherein the electrocardiogram sensors include a conductive textile electrode array integrated in a bed sheet.

13. The method of claim 12, wherein the sheet includes a foot region of conductive textile that serves as a ground plate.

14. The method of claim 12, wherein a conductive pillow provides a return path for electric current.

15. A non-transitory computer readable medium that includes a program that, when executed by a processor, causes the processor to:

receive signals from at least two biometric sensors arranged in a fixed position with respect to a body support, the biometric sensors providing at least one electrocardiogram signal from a body, wherein the at least one electrocardiogram signal changes with body position as a result of the variation of electrocardiogram potential over the surface of the body; and

determine the body position from the received signals using the variation of electrocardiogram potential over the surface of the body;

wherein the processor determines the polarity of a QRS complex of the at least one electrocardiogram signal to determine the orientation of the heart with respect to the respective pair of the biometric sensors providing the at least one electrocardiogram signal.

16. The medium of claim 15, wherein the program causes the processor to compare the QRS complex of the at least one electrocardiogram signal with a plurality of prerecorded electrocardiogram signals in respective body positions and to identify a closest match.